Boyce

I've searched the archives and can't seem to get a clear answer to my questions. I own a stock 85 with no racing. (Don't revoke my man card or membership please!)

My questions: What oil is the best oil for my 928? Synthetic, blended or Petrol based? Viscosity? What filters are best? Additives?

WallyP

Any oil meeting AIPI standards is acceptable for your 928.

Porsche (Mann) filters are readily available from us and the other vendors, and we include the proper oil drain plug seal ring with each filter for $6.50 plus shipping.

Remember that oil is a religion, and that there is thus no rational discussion on the matter.

The most common recommendation is Mobil 1 15W-50.

Old & New

Wally,

Funny & true.

Thread closed!

Big Dave

boyceb:

I found that my 928 leaked (slightly) using synthetic oil. When I switched back to non-synthetic, the leaks stopped. I understand this is not uncommon.

Hope that helps.

Weissach

DO NOT PUT Synthetic!! I put in Mobil 1 15W-50 two weeks ago. Out of nowhere, my car started moking in the morning! My car NEVER smoked. So, yesterday I changed it back to the normal stuff. Problem gone... Every "good" 928 mechanic told me NOT to put it in, but I did anyways. That was a big mistake.

Jim V

On the other hand my '79 with over 100K miles does not smoke nor leak using Mobil 1.
Wally sums it up best.

Brent 89-GT

Keep in mind that the 928 engine was designed to last 300,000 miles between overhauls on dino based oil. So in reality you don't NEED synthetic.

I would also make sure that if you buy synthetic that you do some research. Mobil One now has strayed from true synthetic. I would not bother with blends, how much is synthetic? How much more does it cost?

In your climate I would run 20w-50 or 15w-40 dino based. I would use the MANN filters but, I have used filters from NAPA with no problems for years YMMV. I change most of my vehicles every 5000 miles. Seems to work! Don't put too much thought into it, getting fanatical will not likely show you much benefit in a street car

WallyP

Looks like the religous fevor has started.

goodspeed928

SHOW ME,
A racing team that don't use man made oils!!
By the way I looking for 500,000 mi.

Jim Nowak

Don't use Mobil 1 if you run a supercharger. I tried Mobile 1 in my supercharged Mercedes and it detonated like crazy. Switched to Valvoline synthetic - problem gone!

tdelarm

After purchasing my shark, I switched to Redline synthetic and have burned 1/2 quart in 3500 miles. Have no idea how it ran, how much it burned or what it ran on before I aquired it. It does not leak a drop but then again, I take care of the car and have had all gaskets replaced.

Yes, I do at times run it hard when the timings right.

Tim Delarm

Tom. M

Or if you want to go ultra extreme...pick up the new Castrol TWS (or something like that)...only available at your local BMW dealer...10W60 fully sythetic....widely available in Europe and now brought to the states since BMW now requires it in all M engines.....very slick stuff.....but it runs about $9 a litre (yes...a litre not a quart)....they guy told me to keep the bottles upright since even when the lids are cranked tight..it still can seep out....
Put it in my GT ...to the tune of $72....yikes...had a leak originally..now it's gone...(pure coincidence Im sure)...and usage is about the same....1 litre per 3000 miles or so....

Later,
Tom
(pampering the GT..)...the S4 gets Mobil 1 15-50 :-)

Normy

I chime in with something that a former student of mine told me. He was a chemical/petroleum engineer from Korea, and said that basically, if you do not run a high-boost turbocharger or race your car, then synthetic oil is a waste of time.

I've always had good results with Castrol GTX- 20W50 here in Florida, changed every 3000 miles.

Normy!
'85 S2 5 Speed

Boyce

Thanks for all the replies. Based on the input here and other forums, my car will get Castrol 20w50 with Mann filters and fresh crush ring. However, I will likely change the oil every 5,000 since my driving will be longer road trips.

Thanks again.
Boyce