Overheating question

Dana_Drury · 05-14-2002, 04:39 AM

Hi Guys,

When I had my PPI done, the mechanic had said that the External Thermostat on my 1977 3.0l Carrera was toast because the front trombone oil cooler wasn't getting warm and the car was running at about 110 C+ (230+F) if left to idle for about 20+ minutes or driven. (I would shut it off for fear of doing the engine in so the max I have seen is 120 C (250F) which I know is the max it should safely see for any short time.

I just replaced the Thermostat and again the front cooler wasn't getting warm. The lines running to the cooler have two slight squash marks at front and back though they are far from crushed. I let the car idle for about 20 minutes, with the temp on the gauge reaching just over 100 degrees C (210 F) to give time for the external thermostat to open.

I have just pulled the lines off to have them cleaned out thoroughly and will refit them tomorrow to make sure that the oil flow was not restricted by gunk that might have been in the lines for who knows how long.

I noticed that the new thermostat was leaking slightly from the small bottom cap, so I assume oil is routing through it. Would there be something else to look at or check that might account for the extreme temperatures? While there is a chance my new Thermostat is faulty and isn't opening either, can someone suggest some other items to look at, or some ways of testing for its operation.

Is there a chance my oil temperature gauge is not accurate and I am not giving it enough time to warm up. In general we see ambient temperatures at the moment of about 18-22 C (68 F)?

Any suggestions or help is much appreciated! Thank you.

dickster · 05-14-2002, 05:58 AM

i had grief in this area when i bought my '86.

i have to let the car idle for at least 20 mins to get the thing to open so i can check the oil level - pain in the ass!

i did find out that its rare for them to fail.

how far up the gauge is the needle moving?? mines just short of half - about 8 o'clock. can't touch the pipes at that temp.

someone with the same year may be more help.

Chuck Moreland · 05-14-2002, 07:01 AM

You can check the operation of the thermostat by heating in a pot of oil. You can visually see movement inside.

While you have the lines off also check the trombone for blockage.

Kahuna · 05-14-2002, 08:01 AM

When ambient temps are relatively low (68F qualifies) the engine mounted cooler is sufficient, it has the airstream from the engine fan blowing through it. I would drive the car to really see whats up with the oiltemp.

Olivier 3.0 · 05-14-2002, 08:25 AM

I 'm afraid I'would not help you, but my Carrera 3.0 (same as yours) has also tendancy to heat (about 110 ° C)when driving for a long time at about 160/180 Km/h.
I still have the 5 blades fan, and the trombone cooler; mine is getting hot, so I suppose the oil is circulating. I also thought the gauge might not be accurate, but when I drove a few days ago under hard rain, the needle stayed at 80/90°C, even at more than 200km/h.

I know the 5 blades fan cools less than the 11 blade one, but not that much...

So, I'm resignated to upgrade to the 3.2 cooler,; am I right?