Porsche Enthusiasts Club Forum

Update on my overheating problems - symptom was like the thermostat was jammed shut. ( I tried to post this sunday but it vanished)

Well after ~**###ing about trying to get the thermostat out for about a cumulative 8 hours, my knees my knees, I read up on Rennlist what people do. (The clip eyes were at the 2 pm position at the top and it would not slide round to a more convienient location.)
1 Attack your circlip pliers with a dremmel grinder. get the points the right size and cut a barb on them to stop slipping under compression
2 Make a hooked awl to either pull at the eye or to pull round behind the clip once lifted

both of these proved inspirational. Even with the first I could squash the clip but not pull it out with out slipping. Then after an attempt i saw one end of the clip had risen up. Attack with the awl and pop out it comes. The Rennlist guys also describe using small electrical round nose pliers I did not try this but looks possible. I suspect with a single bar (2.5mm)with a barb on of the right size you might be able to do it without circlip pliers as i had to cut most of the handles off to get even a long nose 90 degree pliers to get in at the right angle. It took less than 30 minutes to get the clip out from the point I started grinding pliers.

Ok so now the thermostat is out it does not stick and works perfectly. So it was not stuck. (this is my long term experience with thermostats since the 1970's, they rarely fail)
I ordered a new thermostat and that was stuck in the local post office as no one was in when it arrived and the post guys were out on strike. Agghh

So I put it back together to test without a thermostat. Car runs perfectly, takes a while to warm up, temp gauge sits around where it normally does about a third on the scale when warm. As soon as it goes above that then the rad fan comes on and it goes back down.

What was wrong then why the overheat? One thing I was particualry careful about this time was bleeding the air out of the coolant although I'm sure this is easier with no thermostat in place to confuse things.

Now I have the new thermostat from the grasping hands of the postal service and I compare with the old - they are essentially identical. BUT for the old thermostat the force required on the bypass section is huge I can barely compress it with my fingers, on the new thermostat its a lot less pressure to compress it. Could that have been the problem - but if so why did it ever work before? So was it the proper bleeding that fixed it?

Today I'll put in the new thermostat and see where I am with that..........

Good news. Sounds like it just wasn't bled propely. You will soon find out when you get the new stat in.

Ive got the same problem at the moment. Not over heating but my header tank always fills itselt to the top. I dont lose any water but it aint right. New cap, new stat, new head, gasket and skim. Bled it 1000 times..... when u take the cap off afetr a run there seems a lot of presure there. Any ideas???

There should be pressure. I never take the cap off when it's hot as you will likly get a fountain of hot coolant. Thats how it's suposed to be! If you over fill it some water will come out as it heats up. A new header tank or cleaning the old one will allow you to see how much water there is without removing the cap. Mine runs between the max & min. If I fill it to the max mark (Measured when warm) some water will come out until it finds it's own level again. So long as the temp is normal thats not a problem.

So I put it back together to test without a thermostat. Car runs perfectly, takes a while to warm up, temp gauge sits around where it normally does about a third on the scale when warm. As soon as it goes above that then the rad fan comes on and it goes back down.

i would have thought with no stat in car would not warm up enough to bring fans on even if left idling for a long while, but i may be wrong