Author Topic: your recommended oil (Read 10337 times)

jpod999 · « **on:** June 18, 2007, 10:14:02 PM »

The time has come to replace my oil. I am just about to hit 224,000 miles and would like to know what oil you guys would recommend to me.

achtungE30 · « **Reply #1 on:** June 18, 2007, 10:41:15 PM »

That would have to depend on where you are? Climate etc..

ABuseO · « **Reply #2 on:** June 18, 2007, 11:22:00 PM »

I think i put 10w30 in my engine once i put the new head back on...but when i change it im probably going to put 40 in it instead.

jpod999 · « **Reply #3 on:** June 19, 2007, 12:10:15 AM »

Quote from: achtungE30;28046

That would have to depend on where you are? Climate etc..

I live in the Bay Area. Right now it is dry and 90-100 degrees.

tjts1 · « **Reply #4 on:** June 19, 2007, 01:14:48 AM »

I use Shell Rotella 5w40 in the gallon container. Can't beat $16/gal for a full synthetic. Diesel rating is another +. I live in the bay area.

RED IS 91 · « **Reply #5 on:** June 19, 2007, 06:05:46 AM »

15-50 mobil 1

achtungE30 · « **Reply #6 on:** June 19, 2007, 07:59:42 AM »

10w40 or 15w50

phredphish · « **Reply #7 on:** June 19, 2007, 10:23:03 AM »

I use 15w50 Mobil 1, have used Castrol Syntec of the same weight previously...

318idol · « **Reply #8 on:** June 19, 2007, 11:44:28 AM »

If you've alway run standard (non-synthetic) oil, stick with it, particularly with an engine with so many miles. Valvoline 20/50 -- or NAPA 20/50, which is the identical product.

This comes from Colorado's finest BMW shop, BimmerHaus, Broomfield. http://www.bimmerhaus.com. Owner Bob Tunnell has won a dozen National autocross titles and been to the road race SCCA runoffs -- all in BMWs. He won a Auto-X championship in a 1991 318is.

Gary

M42Iberia · « **Reply #9 on:** June 19, 2007, 04:43:53 PM »

Quote from: RED IS 91;28070

15-50 mobil 1

+1 in Central Fl

JHZR2 · « **Reply #10 on:** June 19, 2007, 05:09:55 PM »

Ive done a lot of analysis on this, and perform oil analysis and similar functions quite often. As a chemical engineer Ive obtained a lot of knowledge about tribological topics pertaining to optimizing IC engine longevity.

Based upon my analysis for my drivign style and climate, I have found that rotella synthetic 5w-40 is the best. a 10w-30, short of redline with its ester base, will not provide enough viscosity at the bearings, evidenced by higher soft metal readings.

Mobil1 15w-50 is a great oil, but actually provides no added benefor for the most part over a decently formulated 40 wt oil.

Id run rotella or mobil1 5w-40 (both have superior diesel spec additive packages). Id also consider schaeffer's 9000 5w-40 if you can get it (or are willing to mail order it), it is a top notch oil as well.

If your engine leaks or develops a leak when moving to syn, the engine is telling you something. There are some fixes, includng seal cleaners and conditioners, but if it leaks and the car is worth keeping, you ought to be thankful that a leak formed so that you know that your car is in need of PM!

JMH

jpod999 · « **Reply #11 on:** June 20, 2007, 12:04:59 AM »

so either 20w-50 non-synthetic or 5w-40 non-synthetic. That seems like the way to go?

JHZR2 · « **Reply #12 on:** June 20, 2007, 07:07:07 PM »

The chemistry of lube oils, as well as the shear stability of basestocks, has advanced so far that there really is little need for a 20w-50 oil to be used any more. There is something to be said about having enough viscosity at the bearings that we do not wear them prematurely, but once the chemistry of the metals and oil intertwine, and we have a decent lubricating boundary layer, anything else is just power loss.

I wouldnt say that you should use a 30wt, even one that is on the viscous/heavy end of the 30wt spectrum. However, IMO, unless you really thrash your engine in the desert heat all afternoon long, Id say that a 50wt oil is too much as well.

I have found via analysis that a 40wt oil is optimal for protection. It is a bit thinner at startup in a 5w- grade, and it merely sacrifices a little bit of unnecessary viscosity for better flow and cooling properties.

I also see no reason why not to use synthetic lubricants in any car worth keeping and running well.

5w-40 MUST be a synthetic oil, of at least group III (severely hydrtreated slack wax) spec, with some PAO and some ester mixed in, in order to meet the viscosity spread desired. Further, given its inherent use in heavy duty diesel engines, it must e EXTRA shear stable, so this limits the use of viscosity index improvers... that means thatr a syn base is more or less mandatory.

I would suggest to pick a 5w-40 oil and stick with it.

JMH

sheepdog · « **Reply #13 on:** June 20, 2007, 07:20:38 PM »

From what I have read Deisel is best for older engines, at least regarding cam wear.

Many newer oils (which changed just after our cars were made) have less lubricating properties in them. Hot Rod or Popular Hot Rodding (I think) did a test on this because they were getting an abnormal amount of cam failure over the last few years.

I can try to dig up the issue, pretty interesting read, they found Shell Rotella T to be the best for older engines.

jpod999 · « **Reply #14 on:** June 20, 2007, 10:26:25 PM »

So yes or no on synthetic? My car has never had synthetic before.