conventional vs syntheic

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ok i have a 94 buick regal w/ the 3.8 in it. now it tends to burn a little ammout of oil. it has been using conventional quaker state 10W-30 oil all its life. now if i switched to syntheic oil would that reduce the oil burn off. and also what type of oil would you consider the best. thanks


posted by  wjcros

I doubt synthetic would help the oil burning situation. But hey, don't let anyone EVER tell you that synthetic oil can be used longer than the conventenial can be used. Both get contaminated at the same rate. It's a load of crap if you hear otherwise. Always change at 3,000 Miles. No matter what oil you use.

posted by  DodgeRida67

I agree with DodgeRida67 on this one - synthetic oil will not stop oil burning - oil burning can only be stopped by the appropriate repairs (engine rebuild, valve job, etc.)

I switched to Mobil 1 5W40 in my 92 Crown Vic this summer because of the heat we have around Chattanooga and points south of here. I am still using Texaco Synthetic 10W30 in my other two cars although I may switch them to Mobil 1 5W40 I still change the oil and filter in these cars every 4000 to 5000 miles because the additive package blended in the oil will still become depleted no matter if you are using mineral oil basestock or PAO basestock.

One of my relatives has a Mercedes C240 which has a 8000 mile oil change interval. What people typically dont realize is these cars also have an 8 qt crankcase vs a 3 or 4 qt crankcase found in domestics.

posted by  tbaxleyjr

I could see how that could make oil life extend a little, and when I mean little, I mean 2-500 miles. We have some domestics with 7 qrt oil capacities that still go by 3,000. Such as the northstar engine used in some caddies. No matter how much oil you got, dirt goes to the bottem of the pan, where the oil is sucked up from.

As you can see, I don't believe in ever going over 3K miles per oil AND filter change. No one will ever, ever, ever get me to decide otherwise. :laughing:

posted by  DodgeRida67

no one is trying to get you to decide (except for maybe the AMSOIL man) - I am just mentioning what the owners book said in the car. - I won't leave oil in my cars more than about 4000 miles - 5000 max. I do change @ 3000 if the car has been driven hard or seen much stop and go.

posted by  tbaxleyjr

ok thanks, i wont worry about rebuilding the engine for in a few months i wont have that car anymore. but any recomended oil brands. im thinking of switching to mobil 1 ive heard some good things about it.

posted by  wjcros

I personally use Mobil 1 5W40. The most important thing to remember about brands is use one you can recogniz and use the right weight (most domestic cars use 5W30 or 10W30) and API classification (Current warranty oils for gasoline engines are API class SL)

posted by  tbaxleyjr

Synthetic oil flows more easily than petroleum oils, so it will actually burn faster than a regular oil in a worn engine. Mobil 1, Castrol Syntec, Valvoline SynPower, and Havoline Synthetic are all good oils if you do decide to use it. One agent that does seem to slow oil consumption is Lucas Oil Stabilizer (or Lucas Synthetic Oil Stabilizer), which also seems to have very little detrimental effect on the engine, unlike some other "smoke away" agents.

The lucas stuff also increased the oil pressure in my 85 Corolla, which was suffering from a low pressure.

If I sound like a salesman, its because I was. I used to work at an auto parts store. :mrgreen:

posted by  ZanCRX

well, the rise in oil pressure makes sense because any Lucas product is like molasses. I won't use Lucas in new cars because they don't need it, I also won't use Lucas in old cars because I've seen it snap oil pump shafts and blow head gaskets. so, basically, i don't use lucas except in differentials maybe.

As far as reducing oil burn off...step up to a non-synthetic 20W-50, won't get past the rings and valve guide seals as easily...and if your car doesn't see high rpm blasts, you won't have any problems.

Overhead cam engines should use no more then 5w-30, otherwise you'll send the cam and bearings to an early grave, anything thicker takes longer to get to the cams on initial start up.

My preference in my car (with '91 Lincoln 5.0L H.O.) is 5w-30, non-synthetic. My car sees regular trips to the drag strip and 6000rpm's. It runs smooth and smoke free(until 4500rpm when it smokes slightly). Then again it's a ford 302 trade-mark to smoke during higher rpm use, regardless of oil viscosity. I also try to change my oil every 2000-2500 miles, but that's just because I'm a mechanic and anal about maintenance.

posted by  Sick88Tbird

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