shamrock

Yeah that'd be my thinking too ... Surely Porsche would have quite happily ditched the thermostatic system for a much simpler on/off switch , if that's what was called for.

Does anyone have a reasonable explanation as to why Porsche decided on this more complicated system that allows the oil to run to higher temps?

Bull

NOISE. They were scratching to reduce noise in many ways, including the engine cover, and finally had to go to liquid cooling (along with emissions issues).

It is fine as stock, except for very hot, heavy traffic days and track days, where i would use a manual switch. Bruce Anderson has published a chart of the relation of engine wear to oil temp in air/oil cooled engines (as have others likely done). Hotter is not better once past minimal operating temp.

murfysflaw

I obviously don't have insight into the Porsche engineers' minds, but my suspicion is that it would be to keep noise down when it's not needed. Over time, the cars have been softened to be more comfortable, tolerable for non-enthusiasts, so it could be for that reason I suspect.

I am curious about the thoughts on this one too as I'm planning to pick up my new 993 Saturday and this is one item that was in the PPI for it... I initially was thinking I'd just leave it, but if it potentially causes damage, it seems like an easy enough fix.

Bill Verburg

If you are going to track the car in the summer add a second cooler

NP993

Well, if you consider a cycle of engine temps between 180 and about 140, then, sure, the engine isn't too cool. But from everythign I know, that's too cool. This applies to when you're driving in cooler weather, fall/winter/spring. On a hot summer day it's a different story. But where I live, it's cool half the year and runnign the fan on high kept the motor too cold.

TMc993

I'd say that Porsche didn't want to have to depend on dimbulb drivers to read a gauge, interpret the information and manually switch on a cooling fan motor. Can you imagine how many engines would be burnt up by now if cooling a 993 engine was dependent upon drivers paying attention to and interpreting gauges, then taking action?

The people on Rennlist are a knowledgable group, but we don't come close to representing the majority of Porsche owners, and I've met some fairly seriously uninformed Porsche owners over the years (Like the guy whose uncle left him a cherry 911 SC and he sold it for $3,000 because it used oil and he couldn't tell where it was going. He was uninformed regarding the idea of an oil cooled car using oil).

Regarding the noise issue, my understanding was that the noise generated by the belt driven engine cooling fan, along with the emissions issues, were the concerns that drove Porsche to go to water cooled engines. I wouldn't think that electric radiator fan on water cooled cars would be any less noisy than the fans on our oil coolers...Would they?

Just a thought...

Terry

vjd3

I think they look at it differently ... "We don't want the temperatures to get over 250," not, "How can we keep the temperatures down all the time to reduce wear?"

The 2.7 cars had no external cooler; the SC had a useless "trombone" cooler; the 3.2 Carrera got the radiator-style cooler, they added the fan later ... the 964 and 993 really got the best coolers to the point where they took the first cooler off the engine completely. But it's been an ongoing process for them until they finally went to water cooling.

With the SC, the hot setup was to put a "Turbatrol" cooler on there instead of the factory one; on the early 3.2 Carreras, everyone was adding the later fan setup to the earlier car.

But, for example, anyone who adds a second cooler to a 993 for the track is going to run the oil temps cooler all the time, too, it just works "better" than the standard system.

I go by the old advice ... 180-220 is good, 230 is warm, 240 is hot, 250 is too damn hot ;-)

shamrock

Would you have a link to this info by any chance?

Martin S.

if you are concerned about engine oil temps, as the Hulkster says, "Hulk the "F" up...and buy a secondary oil cooler. I have the Ruf unit and the cost was worth the peace of mind. Cargraphics is good to...also Carnewal.com sells a cooler.

96C4S

where would 180 to 220 show up on the gauge 9 0cl0ck position?

Bull

I have only seen it printed in his and Jerry Woods's books.

NP993

911's have always had cooling problems. Remember all the 2.7's with burned valve guides at 60K? That's cause they ran too hot without a cooler.

A second cooler is necessary because an engine will run far hotter at the track than on the street, because you're frequently at WOT and at high RPM's, burning high volumes of fuel, and thus creating a tremendous amount of additional heat. The extra cooler is not to get the car to "run cooler all the time" -- it's to prevent the motor from being completely overheated due to the inadequate factory cooling setup.

Overall, I don't know why anyone puts much faith at all in what the factory does. Our 993's came from the factory with ****ty suspensions, and out of the box they run too hot and had valve guides fitted so poorly at the factory that it's not uncommon for many 993's to need top end rebuilds before 50K miles. And it took the factory almost 20 years to install hydraulic chain tensioners. I could go on. We should trust these clowns?

Dan V

Mine doesn't run too hot. I did jumper the fan relay, tho, (over a year ago) so it starts on "high". Engine is still going strong at 84K, judging from the condition of the plugs and 0il consumption: Qt per 4500 mi. I've been thru some pretty heinous traffic jams here and down south. Probably helps to change the oil with 15w50 Mobil 1 every ~5K.

Cupcar#12

i do not run a fan at all on my 964 - it was fine (temp wise) to SD and back
in the NW i don't need it at all really and it's heavy
another 964 owner i know runs the dual setup w/o fans and has no issues either (mine is a single cooler setup, stock cooler) and he lives in so Cal.

ymmv

personally for a street car i would not worry about it - porsche did a good job on these cars.

pedsurg

Anyone have a link to the graph referred to by Bull ??
And, how cool is too cool ??
(I run aux oil coolers in both 993's)

Jack