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Nissan Quest/Mercury Villager Starting & Stalling Problems

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  • It seems your gas tank also got water. You got bad luck getting gas with water in cheap gas station. As you may know the gas is lighter so it is at top of the gas tank, and water sink down. When you gas tank fill up, you may have no problem for a long while till one day you hit that gas/water boundary. Well, fuel pump can not just pump gas not water.

    Oxygen sensor has nothing to do with this. It simply compares the oxygen left in the exhaust vapor and that in air to tell the computer through voltage how well the fuel was burned. But knock senor will know that when your fuel injector eventually spread water vapor that your spark plug fire not able to burn at generate combustion stage, and it does not like it and tell the computer to give you check engine light on.

    Get a bottle "dry gas" like "Heet" yellow bottle, $2, from auto parts store like Pep Boys or Auto Zone or the like, to pour into your gas tank to treat your gas. i.e. remove water. Since Heet got methanol that sink down to gas tank to bind water into burnable fuel, the knocks shall be gone and knock sensor happy, and check engine light may go away.

    It should not have anything to do with your MAF sensor as if this Mass Air Flow sensor gets dirty, it may not be all of a sudden. However, if you have not done so, next time when you replace your air filter, often recommended by Nissan 30,000 miles, you may want to get an CRC MAF sensor cleaner to spread it, and let it air dry. It is right next to air filter host, so when you remove air filter, it is right moment to clean your MAF. Just 10 minutes about $3 to $5. Don't need to change, may cost you $$ to change.
  • Did you clean your throttle plate or body?
  • Lucas Fuel Injector Cleaner is a very good thing to apply every so often, but it has nothing to do with your intermittent problem because fuel injector either spray or not or low function, pretty much consistent. I do save money on Lucas by buying the 128 oz, i.e. gallon at $30, instead of 32 oz at $10, not to mention 5.25 oz at $5.

    It seems to me your problem is still fuel, and it is simply that you got bad gas in your tank. It is very subtle because gas is lighter and on top of your tank, while water is heavier and sink to the tank. Now, if you never use to very low of your gas tank, you may never hit this problem. However, if you always get cheap gas, over years, your gas tank may have more and more water, and eventually you will still hit the water. When you do, your fuel injector spray water instead of gas, every so often, and that your spark plugs fire not able to burn it and creates knocks, and your knock sensor got the info and feed into your computer that adjust your fuel pump to give you more fuel (in fact, more mix of gas and water). So, you got all sorts of symptom at different situations.

    The OBD II scanner can not tell you the truth because it takes the snap shot of what's going on, and although it can tell you for "repeated problem", the water vapor may hit different cylinders and spark plugs at different time. So, your mechanics may simply advise you to "replace all spark plugs", and it is easier for them to replace wires and distributor ...etc all together as well, but you now can guess it has nothing to do with solving the problem.

    So, the mechanics get crazy like you and would then ask you to replace knock sensor because if now you got good parts and the computer data still give you wrong ones, then must be the sensor giving out wrong data, so ... ,but as now you know it has nothing to do with your knock sensor.

    The correct way to do would be to replace the bad gas, but it would be costly and hard to do by yourself. The easiest way may be just get a "dry gas" bottle like Heet yellow bottle of 12 oz at $2 or so at parts store and feed into your fuel tank that will sink down to meet water and combine into burnable fuel since Heet has other but methanol. Then your fuel injector will spray less, if any, water vapor, and your spark plug will fire to burn it at combustion stage, and your knock sensor would be happy.

    You may ask questions like, well you always get the gas from that "cheap gas station", how come NEVER had problem till now. Or, why your other 2 cars also get the gas from that cheap gas station and running fine? If you know your gas tank has mostly gas on top part because gas is lighter, and some water, may or may not be a lot, sink to the bottom. You can imagine the cheap gas station's reservoir also have mostly good gas on top and some accumulated water sink to the bottom. So, you NOT always able to hit the water, but could be unlucky to get some when the gas station running out of gas before next refill.
  • It seems your gas tank has water, and when you press the gas, the throttle position sensor will convey to ECM to tell how much fuel your really need, together with data from other sensors. However, since your gas tank may have water due to the fact you accumulated from cheap gas station for years, and at this particular moment your gas tank is low, NOT full. So, you finally got exposed to more water than gas.

    When you press the gas, your fuel pump gives out more water that your fuel injector spray water vapor in too many cycles than gas vapor that your spark plug fired can not burn the water vapor at combustion stage, and your engine crankshaft can no longer spin and stall.

    If you are on the road, do NOT press too much of the gas, just let the van go slow and may be press as much as it can take not to stall on you, and go to good gas station such as Moble to fill your gas tank or just add a few gallon, so that your fuel pump won't get exposed to too much water to stall your engine.

    Then you shall go to part store such as Pep Boys or Auto Zone or the like to get a bottle of "dry gas" such as Heet yellow bottle of 12 oz $2 to feed your gas tank that has methanol will sink to the bottom to meet the water to combine into burnable fuel. Then, you will IMMEDIATELY fill the power when you push the gas.

    And, continue to use "dry gas" to "remove more water" from your gas tank every time your tank gets lower, i.e. you are about to reach more water gas mixed in your tank. After a few treatment, you may find your van back to normal and powerful again. How many times really depends on how much water you accumulated through all these years. If you ask around Pep Boys or Auto Zone, they may give you alternative at only $1, the less famous brand like Splash.

    As you can guess why Pep Boys, Auto Zone (AZO stock symbol) all making good money because they placed "more expensive items" in shell for you to buy and make more profit, and in their back storage, they have same alternative, much cheaper. It is like pharmacy, the prescribed drug more expensive.

    I called this Auto Pharmacy. And Auto Mechanics is in fact "Auto Surgeon". In many cases, they make much more money by replacing parts on your vehicle.
  • It is pretty easy to clean IAC valve like this one shows http://www.youtube.com/watch?v=i82s4ZfR2js
  • On the other hand, it may be even easier to just adjust your Idle Speed http://www.fixya.com/cars/t2286144-replacing_idle_control_valve_97 just with a screw driver.

    You may adjust the screw base on the standard way http://www.se-r.net/engine/adjust_idle.html but you may try something creative, knowing the theory behind.

    Basically, when you press the pedal, it really just open the throttle body plate to let go air and the TPS, Throttle Position Sensor, gives the info to computer that tells how much fuel to spread by fuel injector to have correct air/fuel mix.

    But, when idle, you got no air coming through throttle plate, but the preset amount of air going thru the bypass circuit, and the bottleneck was controlled by the Idle Speed Adjusting Screw, so turn clockwise or counter clockwise will tighten the bypass or open up to let go less or more air that in turn rev down or up the idle RPM.

    I personally believe that adjusting this screw is the "engineering intended" way because this screw is so easy to access, especially for my Nissan Quest 94. So, I would adjust it BEFORE considering "clean up IAC valve", and NOT TO MENTION replace IAC valve for hundreds of dollars.

    When I adjust this screw, I was doing like "tuning the radio". I simple start up the engine and after 2 minutes when computer was not reading any initial sensor data, the engine is idling, I use screw driver to tune this screw. I turn it clockwise for one or two turns, and turn it back to original position, and turn it counter clockwise for another one or two turns, and turn it back to original position.

    Believe or not, my engine calm down a lot, and my idle was great, but my Idle Speed Adjusting Screw still back to its original position. I did NOTHING? No, in fact, I have been tuning it to adjust idle air volume and "train the computer" to adjust the internal look up table and formula to obtain the optimal solution.

    If you look at how the ECU works, it really tries to calculate in real time the best way to run the engine like conductor of an orchestra. It has to take as input from all sensors input and look up pre stored table of formula to calculate and send out controls. In other words, it really does NOT need us or mechanics to adjust it manually.

    For example, while engine idle, if you turn on a/c, it will automatically rev up the idle speed just like if you turn on other electric, the voltage sensor will know the load and tell ECU to adjust.

    You can buy a performance chip that is loaded different tables of formula that ECU can look up to make your car much more powerful as the original one has to satisfy many regulations. On the other hand, you can also "tune" your screw or sensors to train your ECU to do much better performance.
  • It seems to me your problem is still fuel, and it is simply that you got bad gas in your tank. It is very subtle because gas is lighter and on top of your tank, while water is heavier and sink to the tank. Now, if you never use to very low of your gas tank, you may never hit this problem. However, if you always get cheap gas, over years, your gas tank may have more and more water, and eventually you will still hit the water. When you do, your fuel injector spray water instead of gas, every so often, and that your spark plugs fire not able to burn it and creates knocks, and your knock sensor got the info and feed into your computer that adjust your fuel pump to give you more fuel (in fact, more mix of gas and water). So, you got all sorts of symptom at different situations.

    The OBD II scanner can not tell you the truth because it takes the snap shot of what's going on, and although it can tell you for "repeated problem", the water vapor may hit different cylinders and spark plugs at different time. So, your mechanics may simply advise you to "replace all spark plugs", and it is easier for them to replace wires and distributor ...etc all together as well, but you now can guess it has nothing to do with solving the problem.

    So, the mechanics get crazy like you and would then ask you to replace knock sensor because if now you got good parts and the computer data still give you wrong ones, then must be the sensor giving out wrong data, so ... ,but as now you know it has nothing to do with your knock sensor.

    The correct way to do would be to replace the bad gas, but it would be costly and hard to do by yourself. The easiest way may be just get a "dry gas" bottle like Heet yellow bottle of 12 oz at $2 or so at parts store and feed into your fuel tank that will sink down to meet water and combine into burnable fuel since Heet has other but methanol. Then your fuel injector will spray less, if any, water vapor, and your spark plug will fire to burn it at combustion stage, and your knock sensor would be happy.

    You may ask questions like, well you always get the gas from that "cheap gas station", how come NEVER had problem till now. Or, why your other 2 cars also get the gas from that cheap gas station and running fine? If you know your gas tank has mostly gas on top part because gas is lighter, and some water, may or may not be a lot, sink to the bottom. You can imagine the cheap gas station's reservoir also have mostly good gas on top and some accumulated water sink to the bottom. So, you NOT always able to hit the water, but could be unlucky to get some when the gas station running out of gas before next refill.
  • Recently, I met a poor but savvy father outside Pep Boys, who also drove an old Nissan Quest. I was surprised to find out that he bought 3 old Nissan Quest, another two to each of his college twin daughters. He is so savvy because he told me he found a job years ago at Rutgers University dinning hall, that way both his twin daughters going to Rutgers FREE of tuition, as children of Rutgers employees, and he has saved huge tuition for past years.

    He was so good on Nissan Quest because he did not make much and needs to support college kids, he maintained all his 3 old Nissan Quest. He said every time he had problem with his Nissan Quest, he would go to dealer and ask for estimate, but do NOT repair there, so he got first hand information on what the symptoms are and what the problems should be. Then, he will go to other auto mechanics to verify and obtain the knowledge as to which auto mechanics are honest and which are not just simply tricked him to replace expensive parts blindly.

    When I asked why he got two extra Nissan Quest for his twin daughters, he said one reason is that van is saver for first time drivers, and when there is an accident, van will be much safer due to the weight than sedan. Besides, the view is much better and can see farther for driver. He chose Nissan Quest because he knows exactly how to maintain Nissan Quest inside out by now.

    One very clever trick is that if he was advised by auto mechanics to, say, change all sparks plugs, blindly, he would just swap the "may be bad plugs" with the "good ones" with another good Nissan Quest, to see if the problem resolved. If not, and the good Nissan Quest replaced with the "may be bad parts" still working great, then he can tell immediately the advise is fake or just guessing.

    Since his Nissan Quest are older than 95, OBD II (On Board Diagnostics II) does not work for him, parts stores like Auto Zone, Advance Auto Parts, Peg Boys, ...etc who offer FREE OBD II scan does not apply to his vans. However, he showed me to get a cheap adaptor over Internet, to plug in that makes his vans able to obtain free scan.

    He also told me the fact there are a few subtle problems on Nissan Quest that are very easy and cheap to fix, but most owners do not know, nor auto mechanics, and by the time they got all their parts replaced by auto mechanics and broke, the problem still exist, they sold their van at good price, so he was very happy to buy them cheap and fix quick and cheap for his daughters to drive. Besides, most of the parts already replaced new. :blush:
  • Let me try to give you the theory behind.

    Your % of water in your fuel tank, fuel line, fuel rail, may be at the threshold of bad and good, that's why 90% of the time it starts and run great, the other 10% it starts hesitating. What you did not describe is these 90% of time when starts and run great is when your water % is below the threshold, e.g. when you just fill up the tank and more % of fuel in the tank. when your gas low and most fuel burn and same water amount but represent more % of water of total fuel left, it starts giving you problem.

    A quick temporary fix may be as simple as go fill up the gas tank, especially, fill up good gas like prime from name brand gas station such as Mobile or Shell ...etc. Just avoid cheap gas station for a few weeks that shall lower the % of water in your gas tank. Once below the threshold, you should be 100% start and run good. No need to see auto mechanics.

    Since the threshold of water % that may cause start stall or hesitation is NOT a fixed number; it depends on the temperature. More precisely, the lower the temperature, the lower % of water will start causing problem that due to fuel injector may spread some mix of water and fuel that spark plug when fire at combustion stage, it will not burn completely, if at all, and that cause "knocks" making your knock sensor unhappy to flag the check engine light.

    You may often fine if there is a problem at the cold start in the morning, or the first start of the day, not thereafter starts during the day. that's because for the same % of water, in colder temperature in morning, the threshold is lower % of water to get by, but once start, and "warm up", the engine went up to 230 degree, it seems fine because with the same % of water, the threshold is higher, meaning, it can tolerate higher % of water to still for engine to run fine. This coincide with the old advise that "old cars needed to be warm up 10 to 15 minutes" as older cars with high millages, say, over around 120,000, may have accumulated good % of water over time.

    It is still very subtle because different people have different habit of fill the tank, some will fill when it is close to empty, some may often fill the tank when it pass below half tank. As you can guess, the first ones may hit the water % problem sooner than the 2nd ones. This also came to another common advise that "when gas tank is filled most of the time, the cars often get more millage", of course, because the water % is lower when filled up.

    So, in the long run, a "dry gas" product may be used to "remove the water" from the gas tank. I used Heet yellow bottle, $2, that has methanol which will sink down to bottom to combine water to become burnable fuel. But I also found Splash bottle cheaper, 99 cents and started using it; however, I often could not find on Pep Boys's shelf; I need to specifically asked them to give me the "cheaper product" to do the same work. Just like you may pay much more for "prescription drugs" and much cheaper on over the counter drugs. But this is the other way around in Peg Boys which often show you the more expensive products and hide the equivalent cheaper ones BEHIND THE SHELF and counter. You need to know and ask to get them.

    As long as you continue getting gas with much less % of water, and remove existing water in your gas tank, your problem will be resolved magically. I still remember the first time I power the yellow bottle of Heet into my gas tank and driving the van out of Pep Boys, I feel like the power increase ten fold. That feeling was very impressive. I called this "Auto Pharmacy" as opposed to "Auto Surgery" often blindly advised and performed by "Auto Mechanics".

    I learned this from a retired Bell Labs researcher who I met at Walmart auto parts department. This old gentleman was so nice and informational because he maintained all his 3 vehicles for decades, and one as old as 1980's still running very well. He was the only one so far I encountered can articulate such problem very clearly like an "Auto Doctor" and gave me "auto drug prescription" and I went to "Auto Pharmacy store" (Pep Boys") to buy the $2 auto drug Heet water remover and it cured the auto sickness IMMEDIATELY.

    So, I am proposing to the governor to find a way to separate "auto surgeon" and "auto pharmacy" and license them, only licensed "auto doctor" should be able to diagnostics your vehicle and prescribe the correct "auto drugs", only in the extreme situation refer to "auto surgeon" (aka auto mechanics) to replace parts.

    ---------------------------------------------------
    '94 Villager recently started intermittent problem with starting and brief hesitation when accelerating after light turns green. 90% of time it starts and runs great, the other 10% it starts hesitating and then the next time you turn it off you can't necessarily start it back up. We had it checked on computer and they said fuel pump needed replacing. We spent $400 on that, to find out we still had the problem. I have read through this entire forum subject. Does anyone out there think this could be the distributor or speed sensor. I think it is a spark problem somewhere.

    Side note -- radiator blew all over the place about two months ago -- possibly affected a sensor or something??
  • rockmobilerockmobile Posts: 109
    nq 94, your are replying to some posts that date back to 2009. Those problems have either been taken care off or the vehicles might have even been sold. Just an observation.
  • nissanquest94's information makes sense and and may allow me to keep driving because I can't afford to replace all the parts that the auto repair guys guess is my problem. Each one has a different solution and they all cost several hundred dollars. Thanks nissanquest94!
  • Your observation is correct, but do you know why I still replied to that post?

    For one reason, we have the same twin van 94 that I know it well; it is a perfect van when I bought it new because my Bell Labs colleagues highly recommend and it was ranked #1 van by JD Power in that year. It is still very good after 17 years, and it really did NOT have all sorts of problems auto mechanics guess in this forum, but, as you may not know, "water in the tank" problem is for all vehicles, even boats, container trucks, ...etc.

    And for another reason s/he mentioned had read thru hundreds of all posting in this Nissan Quest forum and got NO useful solution to his or her problem. So, I feel if I documented here in detail, future members who may soon or later encountered this water problem can benefit from with little cost.

    I have a friend who is auto mechanics who used to make $5 changing oil on demand at client's driveway or even on roadside in New York City. Ever since he learned the tricks from Toyota Dealers, now he already became millionaire and fix cars in his backyard home garage.

    His money making trick is very simple. He ofters EVERYONE referred to him a "free check up", Once people come to his home garage, one at a time go by appointment and everyone thinks his only repair as leisure for friend referral, he would ALWAYS find something to REPLACE, and he shall give you a list to be replaced in the future and REPLACE ONLY ONE part that cause hundreds.

    He would not do any job making money at lower than $250 an hour. e.g. he will kindly refer all to Costco, BJ's or Sams Club for CHEAPER tire replacement. He would even refer people to change oil at Lube Express, Valvoline, Mobile Express ...etc. He would not service old car older than 96 when OBD II (On Board Diagnostics) not works.

    For every car comes to him, he would start REPLACING part by part along the time till ALL parts REPLACED. Eventually, always need to replace "transmission" which cost thousands and he would advise you to buy new car.

    He would always replace dealer parts or expensive parts and easy to replace with less labor time to replace but charges same labor hours.

    His wife would go to all sorts of groups like churches, schools, ...etc and invite all she knows to come to home for "free check up". And when new friends come visit, she would invite them to her nice living room, kids play games, free drinks, cookies, ...etc while husband checking the car, and as you know, unless your car is brand new, he always can find you some parts to REPLACED.

    Recently, I saw a news that police found an auto mechanics fraud in New York City and found $700,000 cash in the house (yes! $100 bills), I thought about my friend right away because he would charge you sales tax if you pay check, otherwise, if you pay cash, no tax. Where are all these cash go?

    I mentioned this story to show all who are good in auto repair how to make huge profit like my friend and became millionaire in just a few years. Of course, I also want to show those who do not have deep pocket how to save money.

    ----------------------------------
    nq 94, your are replying to some posts that date back to 2009. Those problems have either been taken care off or the vehicles might have even been sold. Just an observation.
  • As you may not know, I constantly talked to people I encountered with old cars whenever I met in park, Walmart auto parts, Pep Boys, Auto Zone, Advance Auto Parts, ...etc as if I were doing a rigorous research subject, not to mention doing lots of searches over Internet.

    For example, a guy working at Advance Auto Parts, when I brought up this question, he suggested that my alternator needed to be replaced. So I asked if he knows how to check if an alternator is good or bad, he said he did not know. So I showed him how. Just use digital voltmeter to measure battery at cold to see if it is 12.66v that he knows, and start the engine, to measure again to see if it is over like 14+v that alternator is charging and not over charge at 15 or 16.

    Another one I encountered at Pep Boys who told me IAC sensor needed to be replaced ...etc. Yet another senior mechanics came close to show me "dry gas" product, valvoline 12oz bottle at $3.99, rather than showing me Heet 12oz at $1.99, not to mentioned the undisplayed Splash at 99 cent 10oz bottle.

    So, if you really want to save money, you need to have sufficient information.

    When I asked to buy AuqaSocks http://aquasocks.net/ I was told they do not have; they do not even know what that is, so I had to explain to them.

    ----------------------------------------------
    nissanquest94's information makes sense and and may allow me to keep driving because I can't afford to replace all the parts that the auto repair guys guess is my problem. Each one has a different solution and they all cost several hundred dollars. Thanks nissanquest94!
  • rockmobilerockmobile Posts: 109
    edited June 2011
    Oops! did not know nissanquest94 had a silent audience. Good to hear some 94 Quests are still chugging right along.
  • Yep! and you shall see more because I start sending this Nissan Quest forum to current Nissan Quest owners and prospective owners such as this one http://newyork.craigslist.org/brx/cto/2464961359.html

    When you one day planning to sell your Nissan Quest, you may find the solutions in this Forum helps a lot.

    And, if you planning to buy a "newer" Nissan Quest, you may find the best value price year may be 2004 for year 2011. Why? Because most people in this country finance to buy new car, and in the good old days when new car was not that expensive, people got car loan of 4 or 5 years, but as new cars getting more expensive, in order to keep monthly payment affordable, people start getting 6 years car loan.

    So, once the car loan paid off after 6 full years, many car owners who has little knowledge about cars may simply sell it with the proceeds as down payment of next new car to buy, so all of a sudden, the used cars with 6 to 7 years old are all over the place. as you can see http://newjersey.craigslist.org/search/cta?query=nissan+quest+2004&srchType=T&mi- nAsk=&maxAsk=

    Now, when you see so many 2004 van's for sale, but the price varies so much difference, you may go ahead to get the one with best price. Why? Because now you know Nissan Quest is a great van with a forum behind you, and you know the solution of the water problem that most of others do not. For those much higher prices vans, they may have been "over serviced by dealer" or "replaces many parts unnecessarily", you do not want to pay couple thousands of dollars for that. And, you shall find your capital cost of owning a reliable Nissan Quest 2004 for 10 years is very cheap, only $550 (e.g. $7,000 - $1,500 = $5,500, and $5,500 / 10 = $550). I mean if I sell my Nissan Quest 94.

    What do I mean for "over serviced"? If you listen to dealers to tell you change oil and oil filter every 3,000 miles, your car is over serviced. If you look at your Nissan Quest manual, it tells you to do it at 15,000 miles. All these extra cost spent on a resell Nissan Quest 2004 may reflects on the price. Believe or not, my Nissan Quest 94 has not changed oil and oil filter for past 3 years, and as more car owners I talked to, I get to know it better.
  • Mine has not changed since 2008 and running great; I am wondering if anyone has longer record.
  • When I was at Berkeley many years ago, I was told to change oil and filter every 3,000 miles or 3 months, and if I just changed oil but not oil filter, the oil will get dirty right away. Unfortunately (or lucky?) one time I changed the oil but was not able to removed the oil filter, so what should I do? I was very worry and add the new engine oil and "monitor" the oil change every day. One day, two days, one week, two weeks, ...etc the result was "new oil NEVER get so-called dirty like the rumor says!!!". So, I decided NOT to change oil filter every time I change oil; everything has been great, save some money and hassle.

    Later on I bought a brand new Toyota Corolla 1990, and I decided to follow the manuel to change oil every 7,500 miles and 15,000 miles change oil filter, and it has been great too. So every time I heard people saying "change oil every 3 thousand miles or 3 months", I knew it was a long history myth. Yes, my Toyota Corolla 1990 still alive running very well, and I have not used up the case of oil filters I bought at $1.99 each when I bought the car.

    One day, I asked the owner of a local auto repair service why they tell their customer to "change oil every 3 thousand miles or 3 months", I told him never need to and my car running very well not doing so. He finally admit that "everyone else says so, we have to say the same thing, or customers may think we are NOT professional..."

    So, I told him my other friend making huge profits as at home auto mechanics, always recycle engine oils and "add last quart of new oil" when customers came change oil at only 3 thousand miles or 3 months. As soon as he heard this, he got excited and told me how they did in New York City. He said since there is no need to change that often, and engine oil changed still very clean, so they just "drain one quart of the engine oil at the bottom and add just one quart of new oil on top", when show customer with the dipstick, it always show the top level of clean engine oil just added, and customer happy.

    When I told him even engine lose one quart of oil, the low oil light may turned on but engine still run fine; it may overheat when two quarts loss. He said had seen a customer commute 100 miles a day and came to change oil of his Honda Civic with only one and half quart left in the crankcase.

    I like this one very much http://howautowork.com/part_1/ch_1/Four_stroke_cycle_Engine_6.html that gives you very clear picture of how engine works, in particular, how crankshaft working with engine oil. If you also understand that "new and clean oil is lighter and will be on top of oil tank, and dirty oil is heavier will sink down to bottom", you eventually will develop a very cost effective way of maintaining your engine oil and oil filter.

    My understanding is that engine oil eventually "get thicker" due to heat and chemical reaction, so every 3,000 to 5,000 miles, when you check your dipstick, you see missing 1/4 quart or so, if you follow the manual and change every 15,000, you may lose about one quart. So, if I do not change oil, but "add a new quart of 5W30 on top" I should be fine, and the engine started using the new clean engine oil. But if I have some time, I top up the engine oil every 3,000 to 5,000 miles that even better. No need to change engine oil, nor oil filter.

    Eventually, after many many years, as you can guess the bottom of oil tank will accumulate very thick oil just like gas tank accumulated water, but I know I can remove the water using "water remover" such as Heet or Splash to fill in the gas tank, how would I remove the thicker engine oil from oil tank other than changing oil the traditional way? I found this Engine Restorer http://www.restoreusa.com/Engine_Restorer.html very interesting.

    Last time when I needed to add more oil to my crankcase, instead of adding 5W30, I add a can of Engine Restorer for 6 cylinder. Wow! Amazing! the engine became quiet and quiet every day and every trip till eventually the engine is like new, so quiet, sometimes, could not tell if engine already started!

    Even more interesting, the oil in the oil tank became cleaner and cleaner as if the whole chemical reaction has been reversed. And, of course, the mileage seemed to increase a bit. One senior auto mechanics even said, of course, it is like the Sea Foam thinner. Anyway, after a while when I need to add more engine oil, I added some 5W30 as Engine Restorer $9 is much more expensive than 5W30 oil $2. But now I feel great that my engine is perfect and I have much less worry of my engine as I can use Engine Restorer in the years to come when I wanted to, either engine noise higher or oil darker.

    My goal is to keep my Nissan Quest 94 running as long as possible and as good as it was new. In the mean time, try not to touch "screw", and avoid "auto surgery" to replace parts unnecessarily.
  • Our Walmart never carried Heet for "water removal", and I had to got to Pep Boys to get this yellow bottle 12oz $1.99 or Advanced Auto Parts $2.29. Not long after I started talking about Heet, tonight I found dozen of yellow Heet $1.37 and red Iso-Heet 12oz $1.99 ($2.99 in Pep Boys and more in Advanced Auto Parts) at Walmart auto pharmacy department. http://www.goldeagle.com/brands/heet/default.aspx

    I was very excited to pick up a bottle of red Iso-Heet 12oz $1.99 to pour into my half empty tank of Nissan Quest 94, started losing power again as gas tank going toward half tank. On the way home, wow! the power was increased a lot, I can feel the power even more than the yellow Heet bottle I used before. The red Iso-Heet claimed to have 5 times more "water removal power", and I feel the "throttle response" much more instant and powerful.

    While I was there, a family with 2 kids told me their Toyota Avelon 98 had the problem. After asking some questions, I advised them to buy yellow Heet, two STP red bottle and two STP white bottle and one Engine Restorer for 6 cylinder, and they also got bottle of a/c to refill their not so cool a/c.

    I believe Auto Pharmacy is the future.
  • Stever@EdmundsStever@Edmunds YooperlandPosts: 38,986
    I went 15,000 miles and over a year on my last oil change. Probably a bit much.

    When I lived further up north, my wife would buy a bottle of yellow Heet now and then. After I yelled at her a couple of times, she quit putting it in the tank. Always heard that the yellow stuff was bad for hoses or something like that.

    I don't think much of additives beyond what the oil companies toss in their gas.

    Just burned a tank of gas yesterday and the van is pushing 157k.

    Steve, visiting host
  • I just double checked my Nissan Quest 94 manual, and it says in normal driving situation, change engine oil every 7,500 miles and oil filter every 15,000 miles, so you seemed to be doing correctly.

    As said, as time goes, the engine oil gets thicker and the volume shrink, so if you change engine oil and oil filter together at 15,000 miles, the old flushed engine oil may be 1/2 to one quart short. Does it trigger "low oil light" ?

    I have found it helpful to add some new 5w30, the recommend engine oil by Nissan Quest 94 manuel, to top it off every 3,000 or 5,000 miles or whenever convenient. And, when engine gets noisy, for every 50,000 to 100,000 miles, instead of adding 5w30, I may add a can of Engine Restorer that magically quiet down the engine to like no noise and thinner the engine oil and smell much better.

    And when change oil and filter became once a year or two job and more affordable, I just use the drive thru service like Valvoline, Lube Express, Mobile Express or the like. And, I found this "low oil" light seemed to be a good reminder of either top off engine oil with 5w30, or with Engine Restorer, or with drive thru oil change service.

    When you use these drive thru oil change services, remember to just change oil and oil filter. If they tell you to do other things, just ask for a list of work they suggest and do NOT do it right there. It often very expensive, and could cost you a lot.
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