Engine Oil--A slippery subject

snowman · September 1999

Where did you buy that Exxon oil for $2.99. It is very good price, I have checked many Exxon gas stations but they are asking atleast $3.60.

rondori · September 1999

Snowman,

I saw it at Ames. This is their regular price, not a sale price. Hopefully it won't go up.

-cr

snowman · September 1999

Thank you for quick response. i used to use Mobil 1 before. I decided to try different one and put Quaker State fully synt. perquart is around $3.60.
I am not so sure that it is as good as Mobil.

ruking1 · September 1999

#519
It is probably not if we are splitting hairs, but rest assured it does meet those all important specifications. (SJCC,API, etc, etc,)

16lucky · October 1999

I changed the spark plugs over the weekend, and find one of the old plug (#5 on the V6 engine)is covered with oil. I also see a leak under the engine. Talk to the dealer who said it may cause misfire if I don't take care of the problem and demand $400 to fix it. Can anyone tell me if this is true or should I even worry about it? I have 35,000 miles on my '96 Mazda 626 ES-V6.

Thanks in advance

ccotenj · October 1999

yes, you should worry about it... ask the dealer what he thinks it is, and if it *only* costs you 400 to fix it, you are probably luckier than you think...
good luck... post and tell us what the dealer says.

johncg · October 1999

A few posts claim that synthetic oils make their engine run cooler. How can this be as the temperature is determined by the thermostat. If, for some reason, the synthetic does reduce the temperature, the thermostat will close down somewhat restricting coolant flow and increase the temperature to where it was.

By way of info; If you have access to a BJ's they have synthetic Castroil in a 5qt container for $14.49

ruking1 · October 1999

#523
If the engine thermostat is the only thing governing engine temperature, you might want to try this with DISASTEROUS results; Try emptying the engine oil and run your engine. Care to wager what happens to your engine? Clue, most likely, the thermostat would not be defective

ruking1 · October 1999

#535
Far easier would be to buy that Castrol syn oil @14.49 a 5 qt container, and see what happens on your temperature gauge.

shmang · October 1999

Hi, guys. Whenever I saw a ad say oil change service, it always comes with lube chasis, I don't understand what is that? Anyone here can give me any information like: What part to lubricate, how to do it and what it will benifit? Any information will be appreciated.

div2 · October 1999

In the "good old day" almost all cars were fitted with grease fittings which allowed the various suspension pivot and swivel points to be lubricated. Todays cars do not have these fittings(Though my 1993 Pathfinder DID have @12 plugs which could be removed and replaced with grease fittings).

spokane · October 1999

Johncg, you are correct that the thermostat will modulate to keep the engine coolant temperature constant. If a lubricant is chosen which reduces the frictional heat within the engine, that likely will improve the life of the engine. It would also reduce slightly the amount of heat to be removed by the circulating coolant or other cooling means.

I fully agree with you that such lubrication improvements, assuming the thermostat is functioning normally, would not be seen as a reduction in the coolant temperature.

ruking1 · October 1999

#528

Yes it is app 50 degrees cooler. Not startling by any means.

arjay1 · October 1999

So by using a synthetic oil your engine that was designed to run at approx. 190 degress is now only running at 140 degrees? That means you can save money on coolant and coolant system maintenance my elimanating both. If you are truly getting that benefit than your thermostat is never even opening and you have no coolant flow at all. Your synthetic has allowed sufficient cooling that you are now running an air cooled engine. I had no idea synthetic oil was that good! How come that did not happen when I tried it?

ruking1 · October 1999

#530
Perhaps you are attibuting synthetic oil magical powers it doesnt have. Yes, on a side by side comparison to the conventional oil the syn runs app 50 degrees cooler. It has no magical effect or affect on the functioning of the cooling system, i.e. the thermostat functioning. Like I have said if you think that the only thing that affects heat dissapation in the system is theromstatic control, try running it with disastrous results without engine oil. By your theory the thermostat should regulate the heat in the 190 degree range. RIGHT from that side of the system. MUCH engine damage on the other!! Don't believe it? or afraid to try it?

ruking1 · October 1999

I also take it by your posts that you have not ever seen or had a vehicle run slightly hot to overheating? or even cooler than normal? (past warm up phase of course? Given your theory, how would you explain that?

I agree with you that everything you can do to keep it in a "normal operating range" is what you want to do.

johncg · October 1999

#524
I guess I assumed wrong when I thought we were talking about normal operation.

#525
I have used syn oil only in the winter in my last three cars and all ran at the same temp as they did with DD oil.

Many things effect engine temperature but the final result -- what you see on the dash board -- is determined by the thermostat.

ruking1 · October 1999

#533
Well structurally you must decide whether or not the app 50 degree so difference is worth the switch to synthetic. While results can and do vary, who cares for example; if you trade new every two? Actually, the funny part is that on a theoretic basis, the lower temperature is more critical for conventional oils rather than for synthetic oils.

jackson43 · October 1999

I have never used synthetic oils, but have recently thought about it. Is there any reason to be concerned about changing from a regular oil to a synthetic in a vehicle (Chev 350) with high miles (110K)..?

Thanks, John

shmang · October 1999

Yes, with synthetic oil, it will circulate better, but that only means your cooling fan work less time.With your therm. working properly, it will turn on your cooling fan longer with normal engine oil. That's all about it. It will control your engine run at a temperature it is designed for, doesn't matter what oil you use. Just less or more load on the cooling fan! I didn't see why it will be cooler with synthetic!

arjay1 · October 1999

The thermostat is exactly what determines the operating temperature in a normally functioning engine. Your analogy of running without oil does not work. Of course that would cause your engine to run too hot due to massive internal friction. However, in that case, the thermostat would be open all the time causing constant coolant flow. But, the cooling system is not efficient enough to dispel that much heat and would not do anything to stop the metal to metal wear.
With the exception of heavy towing, driving up Pikes Peak in summer with the A/C running or stop and go traffic in 100 degree plus days your engine should always be running at the normal temp range and this is entirely regulated by your thermostat. There is NO WAY that an normal functioning engine that is running in less than extreme conditions will have the engine temp drop by 50 degrees because of synthetic oil. If you really understand how the thermostat works in your cooling system you would see that what you are saying would mean that the thermostat never even opened. Which, like I said before, gives you an air cooled engine.
I am a believer in the enhanced properties of synthetic oil but claiming engine temp drops of 50 degrees belongs in a Duralube infomercial.

ruking1 · October 1999

No problem there, when the engine temp goes down it is better for the operation. The real question is how that variable works with the system in general. To me there is no misunderstanding. Same thing engine temp drop is app 50 degrees. How that works in tandem with the system temp is also approximate. And yes the thermostat does as you have stated. And you have really stated what the point is. The thermostat alone cannot regulate the total systems temp without some type of lube. So if all you wish to talk of is the themostat, start a new topic. This one last I checked was about engine oil. So I take it you are afraid to drop your engine oil and let your mantra of theromostat save your engine from massive damage eh? Trust me I would be also.

arjay1 · October 1999

I am absolutely afraid to run my engine without oil due to the massive heat generated by the internal friction. As I stated earlier, no cooling system could save an engine in that example.
My postings are not meant to expound on the function of a thermostat but to express my doubt that running synthetic oil will drop oil temp by 50 degrees.
I have never seen this benefit, I have not heard anyone else claim this benefit and I am skeptical.

ruking1 · October 1999

#539 I understand your skeptism. In the old days, and probably now if you really look, you could buy gauges that measured cooling temp and engine temp. But barring that higher temperature in conventional oil, given a normal engine operation will have a tendency to burn off in the area of highest heat contributing to the by product sludge over longer engine life. Safety measures such has changing oil at the 3k or 7.5k mark slows the buildup of sludge over the long term. So really the effect of having oil that runs at a lower temp can be seen as two fold. 1. If you are less than vaporization temp you will tend not turn as much oil product to sludge as a higher temp. 2. less friction, means less wear and less heat build up. Synthetic does #1 and 2 better than conventional oil.

jackson43 · October 1999

Shmang (#536) Thanks, Guess I should have been more specific about whether to go to syn oil at 100K+ miles, my 350 Chev Van temps are all fine, but had heard that I might create an oil burning condition..? I do get that somewhat familar "puff of smoke" when starting it after it sets from the valve seals needing replaced, but that is ok, just didn't want to create another problem if I changed to Synthetic.?

John

hoovee · October 1999

Regarding some previous posts: I've read that syn oil reduces oil temperature, and I believe that it does although my temperature gauge doesn't prove it. The temperature gauge on a car's dash indicates coolant temperature, not oil temperature. I don't know of any cars that have an oil temperature gauge. Maybe some pricey sports cars have them.

jefe5 · October 1999

I am not ready for synthetic oils, but have a rather mundane question about regular oil. My last few cars have said in the maintainance manual that I should use 5w30. Invariable, the quicky oil change place suggests 10w30 because I live in San Antonio. I usually go along with them, or at least I always have in the past. When I bought my 98 town car, I got stubborn and insisted on 5w30. They comply at no extra charge. Now I am getting a Honda oddy and anticipate the same dilemma. I change oil every 3000 miles and wonder if I am doing the right thing in a hot climate (cool in the winter).

ruking1 · October 1999

#543

Yes, in your manual you will probably see the range and it is probably 5-10W -30w.

div2 · October 1999

I run 5W-30 Mobil 1 in my 93 Pathfinder and 5W-40 BMW Synthetic in my Three Series. Don't try to second guess the car makers recommendations. The old "thicker oil is better" saw doesn't apply anymore.

davids1 · October 1999

Have been reading this topic for some time now and I have one question. Many people state that synthetic oil should not be used in new cars right away because the rings need time to seat. Can somebody tell me HOW synthetic oil delays the ring seating process and has this been PROVEN? Thanks.

jcwidman · October 1999

#523

John CG,
I agree with you about engine reduction and have wondered about the several posts that claim a noticeable reduction.

Although the thermostat is not the *only* thing that controls temperature (e.g., a partially plugged radiator will allow the temp to rise above the thermostat set point) it is the main thing in a engine in good condition. Any changes in the oil would be *mostly* compensated for by the thermostat (it is a feedback system).

And, synthetic oil has the same nominal viscosity as mineral oil. Since there is no or minimal metal-to-metal contact, the viscosity is what determines the fluid friction. Since synthetic is supposed to be about the same, where's the difference.

Lastly, engine heat is determined by many factors, such as load, weather, which would swamp out small differences in the oil viscosity friction, even if there was any, and even if there was no thermostat to level things out.

Regards,

jcwidman · October 1999

That is supposed to be 'engine temperature reduction' in the first sentence. Sorry.

ruking1 · October 1999

In days gone past, it was more common to have/or to install, an ENGINE OIL TEMP gauge. Now, I guess smoke in the cock pit is the next default indicator.

ruking1 · October 1999

#550
Also due to the higher viscosity index and also flash point of syn oil, there is a tendency not to consume as much syn oil as conventional oil, all thing s being equal. If your engine is running hotter all things being equal, over a baseline time/miles frame it will show up as say; using a quart more as opposed to not needing to add oil.

My real life example is; my truck tends to use one quart of syn oil at the 14,000 mile mark.

cheapowner · October 1999

Since synthetic oil has less thermal breakdown, does that mean there is no need to install an oil cooler. Assuming frequent oil change and heavy hauling in hot weather.

cheapowner · October 1999

My Astro 4.3L has an oil cooler in the radiator but F-150 4.6L has none. Will an oil cooler makes the oil too cold in cold weather? Will minor drop in pressure affect startup?

ataie · October 1999

I live in Dallas Texas and have been using GTX 20-50 on all my cars (95 Maxima 95k, 96 VW GTI 55k, 86 Porsche 944 90k). I'm however thinking about going to Synthetic. any pros or con? should I run an engine cleaner thought first, then drain and fo with fully Synthetic. I change my oil every 5000 miles. VW requires an oil change every 10,000 miles but I do it every 5k anyways. Reason given by VW was that these days the oils are so good, and due to added detergent in oils, it'll take the first few thousand miles to just burn the detergent, so by changing the oil too often, you can actually damage the engine. Also note that VW offers 100,000 miles warranty on the engins, and says every 10,000 miles.
anyways please let me know as should I go to fully synthetic or blend, or keep using the regular oil.

Thanks for your comments

clintonjohn · October 1999

If you've been good about regualr changes, I wouldn't see any need for a flush. I do wonder about 20w50, though. That seems a little thick even considering Texas heat. As far as 10k miles between changes, my rationale is that an oil change is such cheap insurance, why push it beyond 5k intervals. Assume your car lasts 100k. At 5k intervals, you'd do 20 oil changes, say at $20 a pop. That's only $400 over the life of your car. Or $200 for change every 10k. Isn't it worth $200 over the life of your car for the added peace of mind and protection to change every 5k?
Re. synthetic vs. oil cooler-I cannot imagine the cooling benefit of sythetic vs. dino would be as substantial as running an oil cooler. Seems to be apples and oranges. Why not have both benefits? I also don't think a trans cooler is cooling sooooo much that the oil would never reach proper operating temps and thus sludge up. I think coolers are meant to assist in heavy duty requirements such as consistent heavy loads or towing.

ljutefisk · October 1999

Came across this intersting UK-based site about engine oils. Enjoy.

http://www.geocities.com/MotorCity/2195/engineoil_bible.html

div2 · October 1999

I would switch to a good quality synthetic and change it at the manufacturer's recommended intervals. I would further use the viscosity recommended by the manufacturer. "Thicker is better" isn't true anymore. I use 5W-30 Mobil 1 in my 1993 Pathfinder SE and change it every 6K miles. My two 318tis get BMW 5W-40 Synthetic at @9K intervals. Just my $0.02.

shmang · October 1999

When changing engine oil? I heard that it is good to flush your engine before change oil. (Like pour a can of gunk into the engine, idle for 5 min then drain, put new oil in) Is it good or bad, or doesn't matter? Any comment on that?

popepad · October 1999

You have written one of the most bizarre motor oil posts I've seen. "...burn up the detergent"??
What??? Oh yeah, run that thick 20W50--what
manufacturer recommends that? Hell, change it
every 20,000 miles! Godalmighty.

ccotenj · October 1999

well... i don't believe you can change your oil "too often"... the detergent line is totally bogus...
the reasons why they are pushing it out farther are multiple...
#1) i think that jiffy lube (and others) are primarily responsible for the feeling that most people have that they have to change their oil every 3k.
#2) better tolerances
#3) advances in oil add packs
#4) dealers offering free service at recommended intervals.

the 3k number isn't some kind of magic number... if you do nothing but drive around town 2 miles at a time... then i'd change it every 2k... if (like me) you drive it 70 mi on the turnpike one way to work every day, you aren't exactly overstressing your engine and are safe going past the 3k number. i personally change mine every 5-6k with mobil 1.

live it up. change it every 100 miles if you like. it's not gonna hurt.
ymmv. my opinions, for what they are worth.

sj954 · October 1999

I have a new Silverado, 5.3. How long does
it really take for the "rings to seat". In other words when would it be most effective to start using syn. oil?

Thanks,
Steve

rmoya · November 1999

recently I had distributor assy shaft failure on a 1992 Honda CX 1.5l engine ($340 for rebuilt OUCH).I cant complain though the car has run 115000 without any major repairs.
Upon hearing the shaft failure I inspected the engine and found I had been about 1 to 1.5 quarts low on oil....
Is the oil consumption due to failure of this part or is there a unnoticed leak somewhere? This little car has been very good only work done in the last year was timing belt, valve job, resurfacing head, water pump, and new radiator. When I did remove distributor assy I found small leak around housing that met the block, seemed to be caused by worn o-ring.It was nothing major. I was told by mechanic that the viscosity oil I was using was too light (10w30) for a rebuilt head, high mileage, and driving conditions (80mph about 90miles a day mostly highway) that I should switch to 20w-50 or straight 30 due to excessive mileage.
Is this a correct evaluation? Is a car with 115000 miles and excessive mileage supposed to use more oil than normal? or do I have bigger problems?
Any info is greatly appreciated

rs_petty · November 1999

Would tend to say maybe the part failure was result of low oil. I'm not a Honda mechanic, but would think maybe the distributor came out when you had your head work. The o-ring should have been replaced then. Maybe check the area around the distributor again for cracks or check antifreeze for oil which would indicate head is not seated correctly or head gasket. I assume head was retorqued to specs. Oil weight doesn't make sense to me. I don't see an "or" correlation between 20w-50 and straight 30 weight. Oil is a lubricant not a substitute for wear. Heavier weight oils than recommended will put more stress on your engine. Worn engines will use more oil as rings/gaskets get worn or old. Fact of life. What is your oil consumption? If more than a quart every 1000 then I'd say your in for some big repairs. I'd be checking your oil level daily.

rmoya · November 1999

the head was torqued down within the specs as I did it myself, and the seal did seat properly, but the nature of ANY rubber seal is after long periods of time exposed to heat and pressure, it will fail. Like I said the oil leak was minimal from my point of view. The distributor base could not have failed due to lack of oil, it has a sealed internal bearing that sees no lube. So why it failed is probably due to wear. I thought that the oil consumption was due to misfiring of engine because of bad distributor. I was checking the oil weekly and never noticed that it was not using that much, maybe 1/4 qt every 2 weeks or so. This oil consumption is boggling to the mind, how much is normal?

rmoya · November 1999

BTW, the new distributor base has a new o-ring seal so it will eliminate that possibility from the equation.

rs_petty · November 1999

Your consumption doesn't sound out of line to me with age of engine and mileage you put on the car. If consumption remains the same after the repair I don't think I would worry too much about it. About the only sure way to know where it is leaking or if it is leaking is to get one of the chemical dye kits that show up under a blacklight.

rs_petty · November 1999

Anybody had any experience with Havoline Synthetic? Since their regular oil is usually less expensive I was trying to cost compare their synthetic, but can't find it at local discount stores. I kind of like the idea of getting all lubricants from one manufacturer and Texaco is the only one who makes the range of fluids/greases needed (including anti-freeze). Comments on Texaco lubricants in general?

Engine Oil--A slippery subject

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