Oil Flush....is this for real?

1997montez341997montez34 Member Posts: 202
edited March 2014 in Nissan
I have a 1995 Maxima with 132K on it that belonged to a family member. The oil was very dirty (black) so I had it changed. My dealer told me they recommend doing a pressure flush of my engine. They said my timing chain could be damaged by old oil. Is this necessary and/or effective? I am skeptical when a dealer tries to sell you additional services, but maybe they're right on this one. Anyone know?


  • zueslewiszueslewis Member Posts: 2,353
    sell oil flush products and services - what they don't think about is where the gunk goes when it's "flushed". It hits your oil pump screen, often clogging the pump and limiting or stopping oil flow, which kills the engine (especially and older motor).

    I think it's a crazy thing to do, unless you also have them drop the oil pan and clean the oil pump screen (3-4 hours labor, at least).

    the best thing you can do on a rig with 132K miles is just to keep changing oil frequently and on time.
  • pluto5pluto5 Member Posts: 618
    My oil is always black when I change it every 4 mos. after 2K miles. Engine flushes and trans flushes are a ripoff IMO. I might go for a radiator flush if I forgot to change the coolant for 4 yrs. but I expect to be riding the bus before I lose my memory.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    I have run into similar filthy oil in the past, and changed it, just as you report (although I did the labor myself). Then, about 500 miles later, I changed it again, to get rid of the already darkened new oil. I then went back to regularly scheduled oil and filter changes-- and I ALWAYS change filters when I change oil. This will usually clean them up adequately.
    I have also run a quart of Bardahl to aid cleanup, but that may or may not add much cleaning-- I don't really know.
  • vidtechvidtech Member Posts: 212
    I wouldn't change the oil just because its black.It should darken if it is doing its job.Save your money and change it every 3-4 k miles.
  • zueslewiszueslewis Member Posts: 2,353
    since gunk and corrosion can stop up those small passages. A radiator also doesn't have a filter or screen like the engine that can stop the flow of fluid!
  • alcanalcan Member Posts: 2,550
    Gotta agree there. Regarding antifreeze, permanent doesn't mean forever. It means it can remain in the system year round, but after 2 years or so the corrosion inhibitors are pretty much used up. Much more of an issue with bi-metal (cast iron and aluminum) engines. I've had to replace intake manifolds and cylinder heads because their mating surfaces were so badly eroded.
  • zueslewiszueslewis Member Posts: 2,353
  • 1997montez341997montez34 Member Posts: 202
    I am definitely doing a coolant flush since no one knows the last time it was done.

    Also, is there anything I need to do to make sure the timing chaim doesn't break? And if it does, will it tear up the engine?
  • tblazer503tblazer503 Member Posts: 620
    but I thought them buggers were good for at least 200k before needing replacing? If you feel that uncomfortable, you could probably change it, although I believe it's a lot more complicated than a belt since it has no easy panels to remove... (of course on Honda and Toyota, even easy panels are a pain to remove...)
  • pluto5pluto5 Member Posts: 618
    If you don't exceed 7,000 rpm or whatever the redline is for your engine I don't think I would worry about the timing chain.
  • swschradswschrad Member Posts: 2,171
    GM used to use metal gear assemblies with the actual teeth made of nylon molded over the metal on the main drive gear for timing. this was allegedly for quieting, although if anything would wear in this system, it would be the main gear. I had timing slip in a 76 buick V6 and had to replace the timing set at about 128,000 miles.

    best of my knowledge, to prevent slip issues, all the "interference engines" use cogbelts instead of chains, and you need to replace those at the required intervals (or sooner) to avoid wrecking your engine when the valves and the pistons collide. there are some cases, such as hopped up engines using pop-up pistons and the like, where this may not be the case, such as a few hemi 'cudas I knew of back in the early 70s. but that was aftermarket work.

    in any other configuration, it gets bad, you run rough or not at all, just blowing smoke rings out the top of the throttle plate. it should not destroy things.
  • americanflagamericanflag Member Posts: 400
    I came across this concept at Bob's website and they seemed to think it is a good idea I think. I am just wondering how often it is recommended, the best way to have it done, that kind of thing... also, any negatives to doing a flush?
  • swschradswschrad Member Posts: 2,171
    you have corners of the engine, some oil gallery endpoints, etc. that have big wads of cooked crud in there... left behind by old oil. you put hot solvent in there, even if it doesn't dissolve gasket compound and cause leaks and gasket failures, you are going to stir these demons out of their peaceful slumber. and they will rise up and shudder through your engine until they plug up something else. say, three oil galleries to the back of the cylinder head top, or something equally useful.

    also, when the rest of the loose oilsnot falls down into the oil pan, it's not going to be flowing gently out of the big hole in the bottom. so it will end up in all probability plugging the oil pump screen, and you could have general oil starvation. that wrecks engines.

    I had intermittent oil starvation due to gasket crud in my ranger due to factory issues... and I don't recommend that repair bill to pull the engine, take off the oil pan, replace the oil filter and screen/diptube, mike the crank bearings and maybe the OHC bearings depending on the precision level of the engine, and reassemble it.

    much better to go to very frequent oil and filter changes in my humble opinion.

    unless you are doing this steadily throughout the life of the car, going for an oil flush when it's old and goopy could be real scary.
  • 0patience0patience Member Posts: 1,712
    I agree with swschrad. Whoa, never thought I'd say that. LOL!

    Oil flushing is great for engines that don't need it. But it is harsh on engines that are cruded up. I have seen numerous (as I have stated many times) engines that the flush pushed all the crud into the pan and plugged the pickup tube.

    If you have an engine that is in need of an oil flush, the only way to properly do it is to do the flush, drop the oil pan and thoroughly clean the pan and oil pump pickup and reinstall the pan.
    Not dropping the pan is asking for trouble.
    (Sound like a broken record, don't I?)
  • adc100adc100 Member Posts: 1,521
    I'm the guy that had the dreaded manifold leak to 2 different Corsicas (along with too many other problems to mention here). But thankfully they are both gone. Anyway my son has a 200 GrandAm with the 3.4 engine wich I understand is prone to this problem. Does this problem still occur with the Year 2000 3.4?
    Does DexCool help? And does it make sense to change it at the same interval (even though it advertises a longer interval)?? Does DexCool turn into DexBrick as I once heard? I also use a separate corrosion inhibitor. Any thoughts??

    Since this is an oil thread: I like and agree with your comment on an oil flush.
  • 8u6hfd8u6hfd Member Posts: 1,391
    There are many people who still do the quart of kerosene or ATF in the crankcase, let the engine idle for 5 minutes and drain method.

    My father is one of them....it's proved well for him....a 300,000 mile 2.3L Pinto (before we got rid of it in 1994)....and now the current cars do the same thing (a 94 1.8L Corolla and 93 3.0L Caravan), both with over 100,000 miles with 3,000 mile oil changes.

    the "Gunk" engine flush is basically petroleum distillates.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    My favorite flush is accomplished with a putty knife when I have an engine torn down, with parts sitting on the bench. Next comes solvent with a brush. When it's all done and the engine is reassembled, I like a high pressure blasting for the garage floor flush. There's no end to the things that can use a good flush... (:o]
  • swschradswschrad Member Posts: 2,171
    but then, he does his in plain view, with no mysteries hiding behind steel partitions........

    attempts at laughs aside, you really do always take somewhat of a chance when you are poking in a dark cave with a long stick. there is always the possibility a bear or dragon lives within.....
  • spokanespokane Member Posts: 514
    I agree with Swschad, Opatience, Alcan, Fleetwoodsimca, and others that engine oil system flushing is very likely to cause more harm than help. Even if the oil pump intake screen does not become clogged, isn't there also a major risk of damage associate with solvent being pumped through the engine bearings? A fundamental rule of bearing care is that a film of lubricant must always be present on the bearing surfaces - and solvents are poor lubricants.
  • opera_house_wkopera_house_wk Member Posts: 326
    Almost any fluid will form a hydrostatic barrier. If I was stranded somewhere and low on oil I wouldn't hesitate to pour water in to get me home.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    Now, THERE'S, a nightmare in the making! Shazaaaaaaaaam! Steamed bearings, anyone? (:o]
  • swschradswschrad Member Posts: 2,171
    much better to pour in the spare PS fluid, ATF, etc. if you're out of oil... or... hitchhike for some.
  • 0patience0patience Member Posts: 1,712
    Almost any fluid will form a hydrostatic barrier.
    Well, not exactly.
    The problem with a blanket statement like that is that there are many fluids that will cavitate under pressure. Water being one of them.
    Running water as a lubricant in an engine will cavitate the bearings in very little time.

    Various liquids can only be compressed so far. Once it reaches that point, it implodes (cavitates). Cavitation will literally strip metal off anything and water cannot be compressed very much before cavitation occurs.
  • tbonertboner Member Posts: 402
    that is why antifreeze in your oil is a very bad thing.

    Dumbed down to the third grade level 8^)
  • opera_house_wkopera_house_wk Member Posts: 326
    never worked. Water has a bonding strength close to steel. Cavitation is from expansion not compression. Many rotating machines use water lubrication. Oil/water emulsion is a pretty good lubricant. The advice for using water in an emergency is actually from an article from an SAE lubrication expert.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    You can drive quite a distance on the oil clinging to the metal surfaces, before calamity precipitates.
  • 0patience0patience Member Posts: 1,712
    Cavitation is when water is compressed to a point where the composite of it breaks down and creates a vacuum, which implodes. These implosions are what does the damage.

    The SAE "expert" must not work extensively in hydraulics then. He would then know that the definition of cavitation is;
    [by the way, the high intensity sound waves part is a common problem with diesels]

    Main Entry: cav·i·ta·tion
    Pronunciation: "ka-v&-'tA-sh&n
    Function: noun
    Etymology: cavity + -ation
    Date: 1895
    : the process of cavitating : as a : the formation of partial vacuums in a liquid by a swiftly moving solid body (as a propeller), by high pressure or by high-intensity sound waves; also : the pitting and wearing away of solid surfaces (as of metal or concrete) as a result of the collapse of these vacuums in surrounding liquid.

    Pronunciation: 'ka-v&-"tAt
    Function: verb
    Inflected Form(s): -tat·ed; -tat·ing
    Date: 1909
    intransitive senses : to form cavities or bubbles
  • zr2randozr2rando Member Posts: 391
    Cavitation is when a liquid is caused to vaporize due to a drastic lowering of pressure at the local site due to severe disruption in laminar flow, and it is destructive to material and flow at that point. The navy really worked hard to make the submarine propellers NOT do it so the noise would not give away position.
  • spokanespokane Member Posts: 514
    In your defense, I too would put water in the crankcase - but only in the very extreme emergency that dictated a need to drive a few more miles at the certain expense of a new engine.

    Can you please clarify your remark that "the steam locomotive never worked.."? Thanks.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    ergo an engine can be flushed by using motor oil to wash it out: e.g., the old 'drive a hundred miles on the new oil and filter, then change them.' Cavitation seems to be a different topic, ya?
  • zueslewiszueslewis Member Posts: 2,353
    is my face when I shave!!

    You guys can have all the engineering discussion you want, but water will kill a motor in a few minutes.

    2 minutes worth of common sense will always outweigh a days worth of engineering!
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    This gives new meaning to the popular idea of "park and walk."
  • zueslewiszueslewis Member Posts: 2,353
  • swschradswschrad Member Posts: 2,171
    didn't do thousands of RPM. your typical farm belt-flapper of 10 or 20 HP runs a couple hundred RPM flat out. the pistons and expansion chambers were sealed by oiled leather gaskets... the steam caused the leather to expand, the torque rods through the leather caused abrasion, and oil both conditioned the leather and reduced the abrasion from the torque rods... and the engine operators were always dripping oil on everything from their everpresent oil cans. tolerances were pocket-knife, not ten-thousandths of an inch. there was lots of room for "good enough" then, and no major threat to the oil except maybe starting on fire if you left it next to the firebox too long driving from field to field.
  • opera_house_wkopera_house_wk Member Posts: 326
    I have a water lubricated bearing on my boat's prop shaft that runs at 3,000 rpm and it is still fine after 65 years. Expansion, compression hard to have one without the other. I was working on a liquid sodium ultrasonic whistle years ago and using water instead for the test, for obvious reasons. It would work for about 20 seconds and fade away. The shock waves produced billions of tiny bubbles that adsorbed the sound.

    I've only run out of oil once. Paid $45 for a ride and 4 quarts. Lost the rotor oil seal on my Mazda and it took 19 quarts to get the remaining 110 miles home. The toll both operators had some choice words when I pulled in. No, didn't use water. In certain boating situations it can be more life and death. I have every confidence that that I could easily get an hour of use and the engine would still be in good shape. Clean up is critical as with a steam engine, you don't want to shut them off. There is a difference between good and great lubricants.
  • rayt2rayt2 Member Posts: 1,208
    and never done and never will do an oil flush. It is a sales gimmick aimed at those who know little to nothing about vehicles. The quick change oil places can't survive on just oil changes so they have to come up with another form of soaking the unsuspecting. They tried it on my wife's 2000 Windstar, she went 6k in between a change (even with the reminder sticker I put on windshield for next change interval)and when I checked she was a qt. low so I told her take to Valvoline and have them chenge oil & filter (I didn't have the time to do this time). As soon as they pulled the plug they said the oil was so dirty it had caused damage and they strongly recommended an engine flush. Thankfully she has paid attention to what her husband tells her when it comes to car maint.(well almost, having gone that long in between draws doubts) and told them no.
    My recommendation is run as fast as you can from this sales gimmick.

    Ray T.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    If like me, you don't see satisfactory aesthetics in an oil change that is done so late that the new oil is instantly "dirtied" by a few passes through the engine. Years ago I found myself in such circumstance and did my own oil flush. That is, I changed the second batch of oil (and filter) with only some few hundred miles on the combination.
  • opera_house_wkopera_house_wk Member Posts: 326
    and was a wonderful opportunity to blow the dust off some books. Bearing cavitation is more associated with the rapid shock of a diesel and high speed refrigeration compressors. Cavitation is also very dependent on the vapor pressure of the liquid. This determines how easily a bubble will form and how badly it wants to collapse. Cavitation with cold water is far more damaging than when it is warm even though it is more prone to cavitation when it is warm. This makes the problem very interesting in a gasoline engine that isn't heavily loaded using water as a lubricant. Are there conditions present that would cause cavitation and have enough energy to cause bearing damage? The bubble may just lead to metal on metal wear. At least to me the primary failure mode isn't obvious. I don't think we will be seeing any Mobil 1 vs Evian test results soon. Something to try with an old engine sometime.

    Some methods to prevent cavitation are to reduce operating clearance, increase oil pressure, and change to a higher viscosity oil. As today's 5W20 engines age and clearances increase, it might be necessary to increase the viscosity of the oil to prevent this kind of damage.

    The electric fuel pump is another example of an unlikely liquid used as a "lubricant" to separate two pieces of metal.
  • fleetwoodsimcafleetwoodsimca Member Posts: 1,518
    I would suspect barrier protection at the big end interface to be almost non existent compared to having oil with an additive package lubricating the crankshaft. Water is NOT slippery.
  • swschradswschrad Member Posts: 2,171
    generating large quantities of consistent high vacuum in manufacturing and health care settings. the sihi is a liquid-ring pump that basically operates as sorta-tight pump rotors with a constant stream of water flowing through the pump to form the seals.

    however, to operate sihis, you need a large volume of water at pressure, and it goes straight down the drain. they are driven at speed from AC motors, meaning in the 1700 to 3600 RPM range (I haven't had up-close access to one for 20 years, so can't read the labels right now.)

    the key is large volume at pressure. auto engine lower bearings are built to be lubricated by splash and drip, not run under a pipe-fed pressure band of liquid. you have to rely on the viscosity of the lubricant under pressure and temperature to maintain bearing lubrication in a car engine. and water is gone with a bang under those conditions.

    web-wizards who want to know more: sihi was spun off from siemens in the late 70s or 80s. they are extensively used for medical vacuum in hospitals and large clinics. that should suggest keywords to search with on Google....

    // update // looks like sterling fluid systems makes sihi pumps. see http://www.sterlingfluidsystems.com/
    if it tickles your fancy.
  • 0patience0patience Member Posts: 1,712
    I forget, what was the original question?
    I got lost on the expert opinions. ;)
  • zueslewiszueslewis Member Posts: 2,353
    I was sleeping after all that.
  • swschradswschrad Member Posts: 2,171
    the ultimate sleeping "pill", not habit forming :-D
  • cav_93cav_93 Member Posts: 3
    I have a Max with 32,000 and the dealer recommended scheduled maintenance which includes the changing ATF at $350. Is this worth it?
  • zueslewiszueslewis Member Posts: 2,353
    It is a prescribed maintenance practice. Do NOT follow the dealer's recommendations, follow the manufacturer's recommendations in your owner's manual as far as frequency of service.

    I suggest shopping a bit, because $350 is about $250-275 too high.
  • gslevegsleve Member Posts: 183
    dropping the atf bolt and draining it. Yet if wanted be more accurate you then could (after dropping the atf bolt) drop the atf pan and remove the atf filter and replace with a new one bolt up the pan with a new gasket and fill according to the manual or look at how much was drained and refill accordingly with checks every so often to see if the right amount is harmonizes with the dipstick level
  • fmiller2fmiller2 Member Posts: 3
    Guys and Gals using Auto-Rx.

    Cutting open the filter is not the best indicator of the functionality of the RX product in a non sludged engine, IMHO.

    A better indicator is reduced oil consumption, lower emissions test levels, oil analysis tests that show INCREASED oxidation ( cleaning ) during use, reduced Nitration during and after use ( better combustion efficiency), and finally reduced wear values.

    The reason the large oil companies don't want Auto-RX is that it is expensive to produce and the incentive to use effective and expensive high quality additives in not consistant with the competitive PCMO market.

    Another reason is that Auto-RX can be used effectively with lower cost oils to boost their performance but is not required every oil change thus reducing the repeat sales issues.The larger oil companies want cheap lubes that resell over and over quickly. I suspect many companies are checking out RX and I believe it will be sold in the future once it has become more accepted in the industry as a viable alternative to gummed up engines.

    Understand it was only patented last year.

    Terry Dyson
    Independent Oil Analyst
    ------------------------------------------------------------------ ---------------
  • zueslewiszueslewis Member Posts: 2,353
    it'll never get more respect than snake oil, as far as I'm concerned. Years of hot rodding and racing have led me to believe that the only thing you need to add to the inside of your engine is clean oil.
  • SPYDER98SPYDER98 Member Posts: 239
    I recently had some minor engine work done (oil pan seal and valve stems). I am absolutely amazed at how clean my motor oil looks at the moment. I still wouldn't fork over the extra cash for a flush (dont know enough about it). But even with frequent oil changes, I am still not able to keep my motor oil this clean.
  • swschradswschrad Member Posts: 2,171
    on that "auto-rx" stuff to me.

    the functions of engine oil are to assist in cooling, particularly deep-engine cooling, lubricate moving parts including pressure bearings and the lower piston rod and lower ring, and to collect combustion products and contaminants from around the engine and move them out to the filter, where they can be trapped.

    in the process, oil gets hot, pressurized, and acidified, as well as loaded up with carbon and petroleum gums. when you do that in the right environment with heavy crude oil, you get light fractions and gasoline. so resistance to these conditions is added to oil by tailoring the base stock, blending, and by the additive/detergent package.

    in ugly short condensed form, which is all I can manage with the chemistry I took in high school and college, oil is a short chain of hydrocarbon polymer anchored with one or more benzine rings. to oxidize a chemical compound is to strip electrons off its extremities, causing the compound to become more reactive, attracting neutral to negative ions from the other side of the periodic chart (like metals, for instance). oxidizing a compound also is known in some circles as creating a free radical ion... the health circles particularly preach against free radicals. I have always been told that oil should be chemically neutral to avoid scoring engine parts. oxidized oil is not the preferred state.

    nitrates are produced as combustion byproducts from reacting atmospheric nitrogen in the heat and pressure of an automobile cylinder. in particular, we have moisture from hydrocarbon burning, carbon monoxide and dioxide as byproducts we don't want, and single and double oxides of nitrogen as byproducts we don't want. nitrates in water are nitrous and nitric acid, carbon monoxide and dioxide in water are carbonic acid. acids are not good against metal, they beat it up. part of oil's additive package should be binding with the acids that get past the rings and past the valve seals and remove them from the scene... neutralize what you can, dilute the rest.

    it would seem that if "auto-rx" is not taking up the nitrates, that the additive/detergent package is not up to snuff, either.


    so I'm curious, here, as to how the product can be so great if it's failing in these key areas by fmiller2's reportage. if I'm misinformed, I do seek enlightenment, particularly by multiple sources with standing in the industry, and a body of evidence. this was not my major in college, but I like to think I'm generally well-read enough to recognize technical improvements.

    if I'm not, it's another double-page JC Whitney catalog classic, mechanic in a can version 927.
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