Engine Oil Weight

[ncs]

I came across this article on engine oil. It clears up a bunch of stuff I only kind of understood. It's pretty detailed, but still in plain english.

FerrariChat.com - FAQ: Motor Oil Articles by Dr. Ali E. Haas (AEHaas)

The summary is run the lightest synthetic you can while still maintaining acceptable oil pressure(you'll need a pressure gauge for this). It probably doesn't apply to preventing leaks though.

It also sounds like the best style block heater would be the oil pan magnet kind since the oil takes much longer to heat up than the coolant.

[dennyt]

From the article:

People sometimes use a thicker oil to minimize gasket leaks. This seems obvious to me. Repair the gasket. Do not destroy your engine with an oil that is too thick for proper function.

I'm looking forward to a complete reseal on my somewhat leaky EA82 when it's time for new timing belts at 260,000

Edit - Thanks for the link, what an exhaustive read!

[kir_kenix]

I'm switching to 0w30 with my next oil change. Castrol, Mobil 1, and Amsoil all indicate that switching over from 5w30 will not hurt anything. Theoretical gains are small, but I feel they add up. I think it would allow quicker warm ups. Good advice on the oil pressure gauge, I would make sure your pressure stays up.

[jamesqf]

Only read the first part, but he seems to have missed a pretty important point when he says that engines are designed to run at 212F (or whatever - 195F is the thermostat temp for mine). The fact is that it's not going to be at that temperature a lot of the time. Even a moderately cold winter's day means it'll take 10 miles or more of highway driving to come up to speed, and on a long descent it'll drop to 140 or less.

[RobertSmalls]

I was ready to chime in with the correct answer: 0.8-0.9kg/L, or 7lb/gal.

[ConnClark]

One thing this "expert" is ignoring is that engine gaps and tolerances change with temp too. Some gaps don't tighten up until your engine is at operating temp so more oil oozes through them until things warm up. He also ignores the fact that most oil pumps are geared directly to the engine and will try to pump a fixed amount of oil. This means that dropping the viscosity may not increase the flow rate that he claims makes up for the drop in pressure.

He is also full of it when he says ambient conditions don't make a difference. My car has an oil cooler and a ribbed oil pan to dissipate heat better. Clearly these are affected by ambient temps.

If there was 5w-30 oil available when your car was made and your manual calls for 10w-30 the factory did it for a reason. Stick with what your manual says. This guy doesn't know or recognize all the implications of what he is suggesting.

[MadisonMPG]

I quit reading when I read he had a Ferrari.

[vtec-e]

I used 0W-30 for a while but it made my mleage worse. I shudder to think what it did to my engine.... 5W-30 is the minimum recommended for my car and thats the minimum i'll use.