AO

Dave-

Just as a data point, I used this same oil and after my engine got to full operating temp, I was unable to get the oil pressure above 3bar. Not saying you will have the same issues, just sayin' to watch your oil pressure gauge.

chaadster

Hahahaha! I understand Worf's weariness!

That was a good one, Big Dave.

Big Dave

Didn't you discover that your gauge was not accurate? I thought you saw different numbers on the digital readout.

P.S. I still have your dial indicator gauge (cam timing). I forgot to give it to you on Saturday. I'll bring it next time we get together.

AO

Yes and no.

My analog gauge is not accurate beyond about 3 bar. At 5bar, my gauge reads 4.5bar. When I noticed the low oil pressure, I could not get my gauge past 3bar! So I presume that it was indeed a low oil pressure event.

Unfortunately, it was after this event that I noticed the discrepancy between the analogue and digital readout. I was way too nervous to continue driving the car with that condition so I switched to a 15W-50 and things appear happy, but since I don't drive the car in the winter, I'm not too concerned with the cold weather performance.

Big Dave

I'll watch the gauge carefully. Aside from my current repair effort I've never had pressure issues, but it's always been conventional oil.

The fact that Doug Hillary is using 5w40 helped my decision (no offense Chaad...I see you use it, too).

Mike Frye

Wow. So Andrew were you using dino oil or synthetic (sorry if you have already answered this)? I guess it just lost it's viscosity? It sounds like you changed viscosity, what were you using before?

I don't remember you mentioning this before, did you update your other thread for people who may be looking for oil guage/pressure info in the future?

I think someone else recently had a thread about his oil pressure dropping over the course of a few weeks. I wonder if he changed it and whether or not it had an effect. Who knew that the viscosity could break down all of a sudden like that? I thought it was a more gradual thing.

chaadster

Dave,

No offense taken, of course! I only switched myself (two summers ago) based on Doug's oil analyses and input. Based on the data and the ensuing discussions, it seemed pretty obvious to me that the 5-40 was the superior oil for my application (no racing, three season driving, short trip).

I haven't had any change in oil pressure readings (at idle or otherwise) since switching from...man, I don't even remember what I had in before.

Interestingly, I first stumbled into Rennlist when Doug was posting his fourth report or something like that, and was using 15-50 himself! I didn't yet have a 928, but I remember thinking, "Man, this site is way cooler than The Saab Net forum! These guys are serious!"

hacker-pschorr

I'm still curious if anyone feels the lack of an oil cooler makes a difference. I realize not having an oil temp gauge makes this question 100% speculation, just curious.

The factory never ran a 928 engine with more than 220hp without a cooler. I'm running 400+ without an oil cooler plus a supercharger plugged into my oil system that could be adding even more heat into the oil. This coulc be why my car was not happy with 40 weight. I have no idea.

Hawkeyes

PO used Mobil 1 15w/50 for 10 years. He recently had the oil pan gasket replaced because it leaked.

When I bought the car there was a pretty significant (at least to me) oil dripping situation, but I could not pinpoint the location. I replaced the Mobil with plain old Castrol 20w/50 GTX, changed the filter and added 16oz of AutoRx . The manufacturer claims that synthetic oils will not keep seals pliable as will mineral oils. I have no idea if that is true or not. AutoRx supposedly cleans the crud off the seals over a long period , then allows mineral oil to penetrate & swell the seal thereby stopping the leak.

I've driven over 1000 miles with that combo & have noticed a marked reduction in oil drips under the shark. Where I'd have a little puddle about size of silver dollar, now I get a drip or two.

Anyway, that's my rationale for using petroleum oils rather than synthetic. If I knew for sure I wouldn't get a seal leak, I'd probably go to Redline.

Hawk

RDS928S

Mobil 1 tri-synthetic 0-40

mark kibort

scot is racing a 290rwhp 2 valve 5 liter part euro with a stock radiator and no oil cooler.
its running 270F temps on the oil on the hottest race days.

Ill have to put the temp guage on my engine, and see what it shows. I have 30 more hp and the radiator type oil cooler.

MK

hacker-pschorr

Riddle me this. I was looking up the oil to use for my wife's Audi today.

In more than a few threads it has been noted the first number in multi-weight oils is cold / start up temp only.

In the owners manual of the Audi, it states:
10w-40 should never be used in ambient temps over 80 degrees
15w-40/50 should be used up to 100 degrees ambient temp
20w-40/50 should be used for any temps beyond.

I realize in Wisconsin I'm under 100 degrees 99.9% of the time. I'm puzzled because if the first number is only under certain temps, why would it matter on an 100 degree day if I was using 10w-40 or 15w-40 or 20w-40?

What am I missing here?

AO

The other case of Hacker-Pschorr!

Big Dave

Nothing. I thought the same as you. Those instructions make no damn sense at all.

heinrich

Hacker I think that manual info is incorrect. From the API website (suipports our understanding):