is this a myth/BS or true??

[97tbird]

I was discussing oil-burning/consumption with a few guys at my work place, and this pharmacist, who's about 80 yrs old, and has enough mechanical knowledge to rebuilt an engine, said this: "...in order for the oil to lubricate the top of the engine well, a certain amount of oil consumption/usage is neccessary, and that noone should worry about oil consumption less than 1 qt/1000 miles..." I've never heard anything like this...is he referring to very old engine designs, or is it really true for today's engines, or is it total BS? What do you guys think? Thanks for opinions...

 

[Last_Z]

I think he is partially right....where he is wrong is the dosage...the way he says it, it could be 2.9 qrts or less and that is a lot. Normal compsumption would be something like 1/2 quart for 3k miles of normal driving (no auto cross or sustained periods of high RPMs)

 

[userfriendly]

Ask him to comment and define the chemical reactions necessary for post-exersise ketosis in humans.

 

[Dr. T]

Yes, it's a popular thought...especially pushed by manuf. to blow-off their complaining customers that 1qt/1000k mi. is considered normal depending on driving style, load, condition, etc...so that no warranty work is to be done if within this parameter. I've heard that OHC engines can readily achieve this as some consumption by design is normal and to be expected. Whether this is true or not I don't know...All I can say is I've never owned a car that has zero consumption from day during intevals greater than a 5-7.5k mi..

 

[Hasbeen]

BS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! What`s this oil suppose to be lubricating?? Lead used to be in the gas to cussion the valve seats! Now they are hard enough to be ok without it! The valve guides are lubed from the top with what little oil gets past the seals! Hasbeen

 

[robnitro]

I ran amsoil 5w30 for 13,000 miles, and amsoil 10w30 for 15,000 miles and the most I had to add was about 1/4 qt. The final viscosity in the analysis for both of the oils was around a low 40 weight, so I doubt it was diluted with fuel. I got this honda when it was 90k old, on regular dino changes, and put synthetic in since, and now it is at 140k. Maybe it was from 70% highway driving, but when I was visiting family for a few months in NYC, I still didn't cosume oil even looking at the dipstick. And the oil doesn't smell like gas or the level goes up (so no fuel is leaking in). In NYC the mileage drops from a normal 32-34 to around 26 mpg though. I guess its from a lot of idling and hauling around a lot of people, and the crappy gas there. I think the piston skirt is a big aspect of this. You hear the saturns burning a lot of oil, and they are known for sticking rings. Then you have the LS1 with the looser rings, which made customers complain due to consumption. Maybe because I give my car some gas the pressure helps the rings seat better? The redline is 6750, but the AUTO shifts at 6200 max. I don't think consumed oil occurs up top, only in specific engines, like some VTEC engines have been known to.

 

[97tbird]

quote:

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Originally posted by userfriendly: Ask him to comment and define the chemical reactions necessary for post-exersise ketosis in humans.

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------------------------------------------ userfriendly, here's a link if you're interested in that (no detailed chemical reactions/formulas, though) http://www.sun.ac.za/med_physbio/med_physiology/dept/ketosis.htm

 

[rpn453]

I would be kind of worried if my engine started using that much oil. That's pretty excessive. You'll always use a little bit though.

 

[TSoA]

I dunno, my friend's VAG 1.8t uses zero oil over yearly changes, a turbo! Mom's VW 2.0 has used zero dino oil in 60,000 miles, 2x yearly GTX 15w-40. My woman's Audi I-5 2.3 uses a quarter to half quart in 6000 mile changes, 185k on the engine.

 

[mikep]

Speaking purely from my own experience and not from any sort of mechanical/engine building background......If I had a vehicle that used 2 quarts in 3,000 miles I'd be concerned. I've never had ANY vehicle even come close to burning that amount of oil. I've had some beaters in my day and about the worst oil burner I can recall was a '73 Cutlass (that I purchased with about 150,000 miles) that used 1/2 qt. in 3000 miles. Mikep

 

[labman]

The 92 Grand AM I had with the HO Quad 4 may have used about that much. Since it was within what Pontiac called normal, I never wasted my time complaining to the dealer. At least it had a dipstick. I would say as long as you are not getting the choking blue exhaust, check and top up frequently. We don't have required emission testing here, but I think I did a free check, and it was OK. Where emission testing is required and a car flunks, I am sure the manufacturer would have to fix it. I am not adding oil now between 3 month changes on either my 02 Cavalier (Ecotec) or my 77 Chevy LUV (SOHC). [ November 07, 2003, 09:43 AM: Message edited by: labman ]

 

[Whimsey]

Since an engine that burns oil can poison a catalytic converor I would assume that car companies would not design a car use oil. Since they now have to guarantee the cat for 80,000 miles. Also, I thought I heard that guarantee is to be increased to over 100,000 miles. Now do they build some that burn oil, yes, but I don't think it was intentional. Whimsey

 

[MarkC]

I don't know, my Jeep's 4.0 has almost 90K on it and it consumes zero oil. None.

 

[shortyb]

I have a vehicle that used to religeously consume about a quart inbetween 5K OCIs. Auto-Rxed it and during the past 4K it hasn't consumed any noticable amount. I'm guessing the ring pack is cleaned up and valve seals are working well again. The 1qt/1K theory may be due to engine tolerances, running conditions, or just plain crud allowing the higher consumption. I personally think its excessive given how much better engines are built and how much better oil is these days. I also believe that some manufacturers use this rate to stave off lots of warranty repair work.

 

[Kompressor]

quote:

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Originally posted by shortyb: I have a vehicle that used to religeously consume about a quart inbetween 5K OCIs. Auto-Rxed it and during the past 4K it hasn't consumed any noticable amount. I'm guessing the ring pack is cleaned up and valve seals are working well again. The 1qt/1K theory may be due to engine tolerances, running conditions, or just plain crud allowing the higher consumption. I personally think its excessive given how much better engines are built and how much better oil is these days. I also believe that some manufacturers use this rate to stave off lots of warranty repair work.

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I agree with Shorty, 1qt/1K is unacceptable for a new (and broke in) engine, but as many LS1 guys have discovered, GM would disagree . My old Chev 350 TBI with nearly 200K used far less than 1qt/4K, I feel thats what consumers should get for the high cost of todays cars.

 

[jsharp]

We have a term around here for older engines that use a quart of oil in 1000 miles - "worn out." For newer engines it's a different term - "poorly assembled." "Improperly designed" might also apply. I agree with those that say it's nothing more than a way for manufactures to get out of doing warranty work. IMO any usage more than 1 quart during the normal OCI is excessive in an engine still on warranty. Of course, YMMV... [ November 07, 2003, 11:53 AM: Message edited by: jsharp ]

 

[MolaKule]

I think the old-timer was correct for engines from the 40's to the 60's. I remember people telling me that if the engine "didn't" burn some oil, then something was wrong. I think it was simply expected that those engines burn some oil. I don't think that should be the case for most modern engines in daily driver's, since new ring and valve stem seal technology has mostly eliminated gross oil consumption issues. Add to this the fact that SH to SL oils have lower volatility, and anything more than 4 oz. of consuption per use interval is abnormal today.

 

[Last_Z]

Well, people who Auto X burn a lot of oil due to the high RPM downshifting they do, in cars that would otherwise use very little oil. This is due to the extreme vacuum created within the cylinder when you let go of the gas or downshift at high RPMs.....the vacuum simply sucks the oil past the rings into the chamber.....the total opposite is called blow by......high pressure within the cylinder at WOT forces fuel and dirt past the rings...a lot of crap passes the rings constantly, up and down...so, I believe a small amount of oil is fine.....1 qrt in 3k miles is probably pushing it....more than that and the engine has a problem. Rick

 

[buster]

quote:

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Well, people who Auto X burn a lot of oil due to the high RPM downshifting they do, in cars that would otherwise use very little oil. This is due to the extreme vacuum created within the cylinder when you let go of the gas or downshift at high RPMs.....the vacuum simply sucks the oil past the rings into the chamber.....the total opposite is called blow by......high pressure within the cylinder at WOT forces fuel and dirt past the rings...a lot of crap passes the rings constantly, up and down...so, I believe a small amount of oil is fine.....1 qrt in 3k miles is probably pushing it....more than that and the engine has a problem.

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Thats exactly what my manual says. Good point Z.

 

[MillerMan]

I don't think 1 qt per 2000 miles is all that bad for a V8 with some miles on it, if it's being worked or driven a little hard. if it's a small 4 banger that's different story thou, you have a lot less ring area and valve guides on a four banger heck my grandpa bought a new dodge ramcharger 4x4 in 1975 with a 360 in it, it burned 1 quart in 1500 miles when new, at 90,000 miles it burned the same. he trade it off and was sorry, saying was one of the best cars/trucks he ever owned, it had a little rust, that was the only thing wrong with it. on a side note my 94 mercury Grand Marquis which burns oil is burning less now that I switched from mobil to penz. I changed the oil a month ago put in penz dino 5w30, well I put 2500 miles on it since, it has burned about 1/8 of quart, not bad for a motor with 155,000 miles on it. plus I did some bass boat pulling with too, but it's cooler now, in the hot summer heat it was burning more oil with penz dino 10w30 in it. [ November 08, 2003, 12:05 AM: Message edited by: MillerMan ]