Can your engine run too coo?

UTKarmann_Ghia · 10-15-2003, 07:46 AM

Pat S and I were talking about his engine temps and he was saying that with his new cooling system, he hadn't seen his engine temps go over 180. Although that seems great, I've heard a contradicting view of this. A local P-car mechanic said that the oil temps should get to about 210 to burn off any extra condensation.

Does this make sense to anybody? Why would a Porsche have any more of a chance to build up condensation that other cars? Is 180 truely bliss?

This is the same wrench who said I needed a bigger, front-mounted cooler if I wanted temps under 250

IROC · IROC's Garage

Actually, condensation will "burn off" or evaporate at temps below 212 degrees F. Just because the water in the oil isn't boiling, doesn't mean it's not evaporating.

The 2.7 that was in my car (before the 3.2) never ran over 180F on the street and I am convinced that this low operating temp was a major factor in it's longevity. The 3.2 in my car now doesn't run any hotter than 180-190F and I like it that way.

Mike

Rick Lee · Rick Lee's Garage

Well, if it's too low, that could mean other problems - like a stuck gauge, bad temp. sensor or even a rich mixture. But 180 sounds nice to me.

dd74 · 10-15-2003, 08:25 AM

I agree. My 3.0 w/o external cooler rarely rises above 180 even on the hardest of drives in the hottest of L.A. days. I don't believe Porsche engines have a desired temperature in which they operate at an optimum. In fact, I've had two temperature sensors installed, and with both, the readings were the same.

Any engine that hovers around 180 and below is most probably a very happy engine.

UTKarmann_Ghia · 10-15-2003, 09:14 AM

Ok, well my car runs 210 pretty much, 220 on warm days. But the ext tstat (brand new) opens a bit late, somewhere over 200 (said 90C on the tstat) and I can feel the lines getting warm around 205-210.

Is there anything you can do about this? Maybe an aftermarket tstat which opens sooner? Maybe around the same time as the internal?

So is Gruppe B better or worse than Gruppe A?

1fastredsc · 10-15-2003, 09:37 AM

I believe that the average optimum operating temp of synthetic oil is like 160F to 300F. If an air cooled engine doesn't like high temps, but 180-200 is still well above the oil's optimum temp beginning i'd say your in the sweet spot.

cowtown · 10-15-2003, 09:53 AM

I asked the same question about my 930 engine after installing a big Setrab cooler. It just sits at 180.

The consensus was to consider myself lucky and not worry about it. That's a lot easier than trying to fix it.

Ho Hum 74 · Ho Hum 74's Garage

Good question. I recently fitted an external 70 row (big mother) cooler in my IROC spoiler. I have a Mocal 180 degree thermostat. My car used to always run at 180 degrees WITHOUT an external cooler? Can this be? The PO suggested he fitted a pulley on the engine that made it run the engine cooler (fan speed increased? - who knows.)

Anyway, after fitting the cooler my car will not run over 120 degrees!! WTF? I did take it on the track and it went to 180 degrees but I have NEVER seen more than 120 the street.

I am seriously thinking my guage is not reading correct.

Thoughts?

1fastredsc · 10-15-2003, 11:00 AM

It sounds like your thermostat is stuck open. The reason why 180 is a goal is because 180 is when the internal thermo opens up. If it's stuck open, you'll never get up to operating temp. You may want to check the electrical first, like the gauge, sender, wire that connects to it, stuff like that. After checking those things out, then attack anything mechanical, such as thermostats.

Ho Hum 74 · Ho Hum 74's Garage

1fastredsc

Thanks, I will check the thermostat but there is one thing you should know about the Mocal thermostat:

It is an H configuration and the cross member is always open below 180 degrees. This means (as it was explained to me) that the oil would prefer to go through the H configuration cross member and back to the engine instead of going to the cooler. When it reaches 180 degrees the cross section closes up and forces the oil to make the trip to the cooler.

I can't understand what's going on here unless it is stuck in the closed condition.

What is the ramificaiton of not getting the internal thermostat to open up?

Just after I installed the cooler my number 3 big end rod bearing failed at the track. The oil temp went to about 180. I did about ten laps and the rod started knocking. I'm rebuilding the engine as we speak.

Thanks for the insight.

Tristan

Pat S · 10-15-2003, 03:30 PM

I ran my engine without the external cooler at first after my rebuild to avoid getting all the metal from the first couple runs in the cooler. I hit about 220 or so. I then hooked up the 40 row mocal and as soon as the mocal termostat opened at 180, that's where my gauge stopped. It was very cool

Anyway I boil tested my internal thermo and it starts to open at just about 185 and is fully open about 190. Is there a problem if the external opens before the internal? I can't imagine there would be any problem, I mean after all the first 5-10 minutes of every drive would be too cool to open the cooler anyway right?

Pat