What oil do you use?

[studawg]

Whats your climate? Generally speaking that oil is to thing unless you live in north dakota or alaska and then only use that during winter. Our cars call for 20w-50. Many synths come in 15w-50 which is acceptable.

I live in South Carolina.

[studawg]

ZDDP in the 0w40 is too low for an M20. low ZDDP = trashed cam lobes.

the next closest thing would be 5w40 turbodiesel truck, which likely has enough ZDDP, but it's not cheap.

BMW now recommends the same oil no matter what engine you have, pretty much. also, they suddenly started doing things like 15k oil changes and "lifetime" fluids. coincidently, at about the same time they started paying for all the maintenance on new cars. Think about it.

Ok, I thought thats what your were saying about the 0w-40.

I run Rotella 5w-40 T6 full synth in my Ford 7.3L diesel, love that stuff. Running 10k mile oil changes with Mobil 1 extended performance filter, oil samples taken and sent to Blackstone with amazing results.

Regarding BMWs service intervals, I used to think the same thing, but then I figured out that their 15k oil change recemmendation actually coincided with their change to full synthetic oils, across the board.

[studawg]

Ok, another question. Im just trying to understand the logic behind this.

M1 0W-40 is BMW LL01 approved, longlife, the 15w-50 is not. Does that matter?

The M20 doesnt have flat tappets, and 15w-50 is designed for high performance or flat tappet applications. It has higher zinc levels, but the 0w-40 has 1100, which I would think is enough. Is the only reason yall are running the 15w-50 over the 0w-40 because of the weight/viscosity?

[digger]

1100 is hardly what i would call low

[studawg]

I think im going to the M1 15w-50. I dont like to switch oils at all, and I think I can run it year-round.

[jrockbk]

What oil do you use?

Motule 10/40 syn blend, I live in north east USA

[dnguyen1963]

In SC, you can run 15W50 all year round. Be careful about going synthetic. Some users have seen big time oil leaks after switching over to synthetic.

[jrockbk]

In SC, you can run 15W50 all year round. Be careful about going synthetic. Some users have seen big time oil leaks after switching over to synthetic.

I read in the e30 BMW owners manual that BMW specifically states to avoid using full synthetic oils in the car and to only use natural or synthetic blends, and the recommended weight is 15w50 but if your in colder climates 10w40 is in range

[jrockbk]

you should be running 20-50 year round. non-synthetic. and replace it every 3k.

Why? That seems too thick for cold starts and every 3k? Why?

[pantelones]

i wonder if just looking at oil temp and pressure gauge is a good method to tell you if you are running a suitable weight?

Digger, that's exactly how you tell if you are running a suitable oil weight... 10 PSI per 1,000 RPM's is the rough rule of thumb. This is dependent on OIL temperature, NOT ambient temperature. No one here is running an air cooled engine, right? 10Cs at 212* for street engines, and 302* for racing applications.

For anyone who actually want's to wrap their head around oil (aside from the in-depth chemical composition)

http://www.bobistheoilguy.com/motor-oil-101/

I am really starting to be leery of the whole ZDDP debate, and would really like to see an objective test run with modern oils and the actual ware that occurs. Too much Zinc is corrosive, and defeats the purpose of adding it.

[Cabriolet]

Why? That seems too thick for cold starts and every 3k? Why?

you can run thinner in the winter, bc it gets cold there. for us in CA it rarely even gets to 32F. so 20-50 is perfect year round. however you need to run 20-50 in the summer.

As for every 3k, this should be obvious.

[dnguyen1963]

Unless you rev the hell out of your car, the oil should last 5k easily.

[digger]

if you drive the car and the oil gets upto temp for a while it will last longer and help burn off the contaminants. if you do cold starts for short trips and the engine hardly gets upto temp then more frequent changes are needed

[pantelones]

if you do cold starts for short trips and the engine hardly gets up to temp then a thinner oil is needed

Oils viscosity is rated in centi-strokes, and most (basically all) manufactures desire a value of 10Cs at operating temp (the longest intended interval of use). If you never reach operating temp, then your application calls for a different oil to properly lubricate the engine. The lifespan of the ware, thinning, and thickening additives to my understanding are not adversely effected by the temperature of operation, but rather the duration of operation. I would have to read the article again to verify that, but seriously, read the article I posted...

[digger]

Oils viscosity is rated in centi-strokes, and most (basically all) manufactures desire a value of 10Cs at operating temp (the longest intended interval of use). If you never reach operating temp, then your application calls for a different oil to properly lubricate the engine. The lifespan of the ware, thinning, and thickening additives to my understanding are not adversely effected by the temperature of operation, but rather the duration of operation. I would have to read the article again to verify that, but seriously, read the article I posted...

im not talking about viscosity, yes if your oil runs colder it needs to be thinner. did i say otherwise?

it still doesn't change the fact there will be more moisture and fuel contamination in colder oil even if it is the correct viscosity,compared to an oil that operates at higher temperature