macfly4

I have been reading back over old threads on engine oil types/viscosities while trying to decide what to run in my 87 s4 which will be a year round car, less in the winter, with normal temps (d.c./maryland) being probably 50-105 for 2/3 of the year.
it would seem to me that if you will have winter driving you would choose a 0-5 weight cold weight with a 40-50 hot weight given that usually we will be seeing temps (with global warming and all ) getting hotter in the summers.
if you were going to keep the same oil in all year wouldnt a 5-40 or 5-50 be ideal?
i guess if you changed it between the winter/summer you could use a 0-5/30-40 for winter and a 15-20/40-50 for summer months?
Do i have the thinking wrong on this one?
(oops. viscoSity. my bad)

jon928se

Sounds about right to me, but.....

If I was going to operate the 928 in a cold climate - given this is an international list I won't add to the confusion by quoting temps in degrees C, and I can never figure out cold temps in degrees F - cold climate means weeks on end where it stays below freezing. Then I would consider using 0W or 5w something.

However if you live somewhere like the UK for example where whole days below freezing are rare then no real need.

I think it's more important to deal with the higher temperatures. The 928 engines should warm up very quickly compared to other cars even when the outside is cold. A 50 oil seems appropriate then.

Off to bed now - it seems cold enough here in OZ to freeze the ***** of a brass monkey - roll on summer.

hacker-pschorr

Some good info here:
https://rennlist.com/forums/928-forum/366268-the-oil-viscosity-poll.html

I disagree about the oil in a 928 heating up faster than most other cars. A 9+ quart sump is going to take a long time to fully heat up. These finned aluminum oil pans do a good job of pulling heat out of the oil.

If my 100,000 mile lifters didn't chatter with 40 weight, I would be running 5w-40 year round vs. 15w50. I probably have damaged lifters the heavier oil helps keep quiet. I'm never going to use Syntec 5w-50 in any car I own ever again, so that weight is ruled out.
These cars are getting old, not every one is going to react the same. A fellow 928 owner / rennlister in Chicago runs 5w-30 on his S4 year round with no issues. Whatever the lowest weight that maintains good pressure when hot is the weight to go with.

macfly4

so would it be safe to suggest using a 15-50 if i am living in Maryland? there were a lot of jokes about mobil 1 but is this something i should stay away from?
im sorry if these oil questions get annoying to you old timers but for some of the newbies on the board just going through all the old threads does not shed as much light on everything. hopefully im not bothering folks by asking.
thanks in advance

Jim M.

That is the key point! I'm currently running Mobil Delvac 5w40 in my GTS. Yesterday on my way to a local GTG I had oil temps of 220 deg F climbing up to 240 Deg F in stop and go traffic. (A/C on the whole time.) Water temp never got above the last white line. Got a low oil pressure warning several times when stopped for traffic (the gauge never went below 1 bar). When cold I get 5 bars, when hot the best I can do is 4-4.5 bar. Well this weekend the Delvac is coming out to be replaced with something else. Thinking about Redline or I need to find a Amsoil dealer in the area.

Jim Mayzurk
93 GTS 5-spd

Art_Z

I use 15-50 (amsoil) in PA and drive year round, though my car is a not a DD (looks to be about 5 to 6k a year).

The engine oil does take forever to warm up, compared to my Subaru WRX and wife's Nissan Armada, both which take about 5q of oil.

hacker-pschorr

Mobile 1 is fine. Almost every ZO6 I know used for DE's runs Mobile 1 with no issues. These are the C5's not the dry sump C6 cars either. Their lap times are on par with most 928 race cars (all but Anderson, except one did reach a low 2:20 a few weeks ago, not sure the oil he runs).

The ONLY reason I have a stockpile of Royal Purple is Napa had a huge sale, it was cheaper than Mobile 1.

Alan

Jim - I have had similar issues - did you add an oil temp guage specifically to monitor this? I am convinced my oil tends to overheat (also in traffic) - while my mechanic says its fine... I need to get a guage too.
I had issues with 5W40 also but running M1 15W50 works much better for me. I have no qualms about Mobil1 - its been in the car since new in various formulations - but it likes 15W50 best so far.

Have you considered adding a second oil cooler - back in the radiator side tank per prior stock loc'n? I've considered this but assume Porsche dropped it due to concerns on total cooling capacity for the larger 5.4 engine output - however I (and you) seem to have oil temp problems not water temp problems...

Have you already swapped/tested your oil thermostat?

Alan

hacker-pschorr

I need to get that oil temp gauge installed, now I'm really curious.

Jim,
Where do you have yours installed? Mine will be installed into the sandwich plate on my oil filter. This will tell me the temp of the oil before it enters the engine.

macfly4

excellent! thanks for the posts...so from the sound of it 10-15/50 is the way to go. will be using that at first oil change...

hacker-pschorr

Wel, kind of.

If your car holds good oil pressure and the lifters are happy (no ticks) with Xw-40 then I would run that. Notice that Jim who talks about high oil temps lives in Texas. Alan is in Arizona. I would have to do a few laps around Road America to reach the oil temps they do in normal driving.

I tried 5w-40 on my car, oil pressure was a bit low at idle and my lifters started to click. But my engine has 100,000 miles and has been beaten up more so than most 928 motors. I'm still shocked it runs, much less with 9psi of boost.

I think Z runs 5w-30 in his S4 with no issues.

jetrainor

I just changed out to 5-30 Royal Purple after running Mobil Delvak 5-40. Any opinions on Royal Purple?

87 euro auto

hacker-pschorr

I've been running RP off / on (when available) in my track car and now in my street car and replica Cobra.

So far nothing negative. Like I mentioned before, I'm only running it in the street car since I found it dirt cheap on sale locally. So I bought a couple of cases.

macfly4

ok. i was getting the impression people were worrying more about having good viscosity at the bottom (cold) end so going with a 10-15/x would be a good place to start...
so start with 10-40 and see how that goes and then move to a 10-15/50 if you notice ....what? temps are too high? but most of us dont have oil temp gauges so how would we know? what would be the signs to look for that a 50weight would be a better call than a 40?

Jim R.

My next oil change will be to the Castrol 10w-60 used in the M3's. I've had no issues with M1 15w-50, but if the castrol 10w-60 is what the BMW factory fill went to for the M3's after they started with rod bearing issues, it certainly couldn't hurt with our cars. Only problem is $10/quart.

Jim