azmi951

A different water pump, different head different cooling circuit....they are very different but as everyone has said, the first white line or 80c is normal.

ehall

That's kinda funny. Let's just use your premise that you wondered if lower viscosity oil was creating lower cooling temps.
Well how about an oil cooler? Do you think that is a SMALL difference, between a 924s and a 951? ROFL.
AZ already handled the rest of the differences.
Unless you are running a car on the track, there are very few (read almost NONE) cases where the oil is going to get so hot that it will heat soak the coolant to a point where the oil brand or viscosity will EVER make a significant difference...damned sure not in a street car!
Even with lighter viscosity oil, you aren't going to see any actual difference in a street application, in terms of performance. You aren't on the street looking for 1/100th of a second over the course of 50 laps.
Sometimes it's astounding how much effort gets put into meaningless tech, by the owners of street cars, on this board.
If you aren't going racing, run the oil that best protects your engine. PERIOD.

Jeff N.

Funny, I just noticed my car doing the same thing (and I'm just up the road from you). I don't recall it doing this last winter. I did have the thermostat cooling housing off this summer and wonder if I might have mucked something up when I put it back together (ala Special Tool's comment).

Keithr726

I thought mine was the only one that did this.

333pg333

Did your engine builder suggest running such low visc oil during a run in period? Why did you need a new engine? What oil were you using before? You know the Porsche handbook suggest 20w/50 even in sub freezing conditions. Sure, your 10w/30 is there too but unless your after extended fuel economy vs extended engine life you might consider moving up in weight after a few more miles.

porschefig

IIRC my 951 is still right (goes up to full) but my 944 NEVER reads full. You're not alone!

Jeff N.

Doesn't a low coolant temp impact the operation of the DME? Not sure what all coolant temp triggers in the DME, cold run for sure.

Techno Duck

I read something a while ago that said the DME comes out of open loop with coolant in the block around 85-90*F. With a digital temperature gauge and wideband you can see the changes happening almost in real time. On a cold start the car will idle at about 12-12.5 : 1 AFR and as the temperature comes up, it will start to slowly move into the mid to high 13 range. For a few moments it will actually build up to the high 13 range, then come back down into the 12's and cycle this way for 3-4 times before finally settling at around 14.7 . My guess is this action is a result of the coolant temperature in the block being right at the cusp of telling the DME to come out of open loop.

But if your DME never came out of closed loop, the car would run pretty rich at part throttle and idling conditions. I dont think this would ever be a problem with the car never warming up unless you were running your car in the winter with no thermostat or the DME sensor was bad.

I dont know what the temperature is in the block actually during this period because the thermostat is still closed during this period. On my digital gauge, the temperature comes up slowly but at a steady rate until about 90*F in the upper radiator hose. After this point, the temperature comes up fairly quickly to about 120-130*F when the thermostat opens.

Keithr726

It seems after installing a maf my car warms up (leans out) quicker. It used to take forever to reach 14s and now I see 13s pretty quickly. Maybe its the maf chips set differences.

seattle951

I didn't need a new engine. There was nothing wrong with the stock motor other than I wanted to upgrade. I wanted a lighter crank, rods and pistons.

The engine builder recommended 10W-30 because of the upgrading oil cooling system and tight clearances. He wanted a thinner oil that would flow better through the auxilary oil cooler in the fender well. He also pointed out that the manual was 25 years old and that oil technology has improved significantly. He adamently recommended against 20W-50 for this engine and the cool Seattle climate.

ehall

333pg333,
You should go over to Clark's and read up on seattles build. He's put LOTS of time and money into his car. I think I've followed it for something like 6 years. His engine should have like new tolerances. He can probably run a very light grade viscosity oil, compared to most.
I don't think it will affect his coolant temp, in a street application, but I suppose it could, marginally, on a hot summer track application.

lleroyb

Seattle's car is very trick indeed. I live in Maple Valley too and I am noticing my car running about the same temps and oil pressures he is, albeit on Redline 20W-50. Next change I am thinking of using 15W40 Redline.

Lou