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| Engine running too hot? https://forums.tipec.net/viewtopic.php?f=25&t=9062 |
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| Author: | doctor924 [ Tue Jul 20, 2010 9:55 pm ] |
| Post subject: | Engine running too hot? |
Hi All Been running around in my project 944 and think its running a bit hot. The thermostat has been changed and opens at 80 degrees. The radiator fan switch is new and I've done my bet to bleed the coolant (which shows no signs of rust/oil contamination). The temp gauge climbs steadily to approx midway - but has a tendency to edge to wards the 3/4 mark - at which point the fan starts. This controls the temp but in my mind the fan is being triggered too frequently and even after relativeky short runs and easy engine use. I don;t think this is normal and welcome suggestions on posible causes? I'm thinking of: 1) Partial radiator blockage? 2) Still not fuly bled the coolant 3) Running too lean Anything else? Thanks (oh its a 2.7 model) Ian |
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| Author: | met [ Tue Jul 20, 2010 10:01 pm ] |
| Post subject: | Re: Engine running too hot? |
mine does exactly the same mate, im pretty sure its normal but will be monitering this thread too, i suspect i have a blockage from when i changed the thermo switch too, how did you go about bleeding it? |
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| Author: | tr7v8 [ Tue Jul 20, 2010 10:38 pm ] |
| Post subject: | Re: Engine running too hot? |
With a new stat this sounds about right. |
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| Author: | doctor924 [ Wed Jul 21, 2010 5:39 am ] |
| Post subject: | Re: Engine running too hot? |
Hmm. OK - thanks I'll keep an eye on it. Its just that the fan more often than not, comes on when using the engine gently I've bled trying the methods recommended - raising front of car when filling/opening top hose screw, squeezing top hose, and frequent rebleeding after use. Thanks Ian |
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| Author: | J.J. [ Wed Jul 21, 2010 7:27 am ] |
| Post subject: | Re: Engine running too hot? |
My '44 has a new stat & water pump. Also a new rad' Running on the dyno for an extended debug (10 in the morning until 3-30. it was running bob on the three quarter mark. Looked too hot. But a temperateture probe on the head & hoses showed a maximum temp' of 90 degrees which isn't bad at all. Guages are over sensative it seems. I've only done 1500 miles since replacement so will watch how it goes. If your not sure you've bled it right try drilling a 4 mm hole in the stat'. I've heard this helps. If worried about the temp then you should check with an external probe to be sure. |
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| Author: | AndyG [ Wed Jul 21, 2010 10:59 am ] |
| Post subject: | Re: Engine running too hot? |
Hi, I changed my stat and rad switch earlier this year, and wondered if it was all working normally. Mine works exactly how you've described it above, so it must be about right. |
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| Author: | stratfordshark [ Wed Jul 21, 2010 11:16 am ] |
| Post subject: | Re: Engine running too hot? |
tr7v8 wrote: With a new stat this sounds about right. Jim is right as ever! New thermostat usually results in higher running temp initially as spring is so stiff, at least in comparison to previous t-stat if that was working normally. If you're concerned about bleeding system fully, warm up from cold with heater full on and expansion tank cap off. |
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| Author: | MisterGT [ Wed Jul 21, 2010 11:43 am ] |
| Post subject: | Re: Engine running too hot? |
doctor924 wrote: Hi All The temp gauge climbs steadily to approx midway - but has a tendency to edge to wards the 3/4 mark - at which point the fan starts. This controls the temp but in my mind the fan is being triggered too frequently and even after relativeky short runs and easy engine use. Ian I also had a new thermostat fitted a few weeks ago and mine performs exactly like that. |
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| Author: | met [ Wed Jul 21, 2010 12:27 pm ] |
| Post subject: | Re: Engine running too hot? |
so we are all good, and i didnt bleed mine at all although i didnt loose too much coolant on the temp switch changeover, i have been doing at least 60 miles a day for the past month in the car since its been like that in the hot weather etc and she runs perfect in the hot weather in traffic creeps up to 3/4 and come back in and stays at half way in heavy stop start traffic and hot days, cooler days and free running (motorway not traffic etc, just under halfway point) |
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| Author: | scam75 [ Wed Jul 21, 2010 1:12 pm ] |
| Post subject: | Re: Engine running too hot? |
Mine has being doing exact same with a brand new 80 degree stat, although after a lengthy run it will go to 3/4 at idle, the fans will come on but be unable to knock the temp back. The temp will only come down if I whack the demister button on, although not back far enough for the main fans to cut off. This has led me to believe the new stat is not opening very much. Flow must be ok as the heater matrix seems to have a cooling effect when the demister is applied. My car will run just above half way under normal driving conditions and get close to 3/4 when in traffic. If I leave the demister on full time it runs happily just under half way without moving? NB. I changed my stat about 3 months ago and the car was running just over the first mark and rising to half way in traffic. Fans would come on and knock back down just over first mark. For no apparent reason car started running up close to the 3/4 mark with fans unable to knock temp back. I assumed faulty stat and what I explained first is what's happening with the newest stat. Both items incidentally QH stats. Thoughts? I have ordered a genuine porsche one to see if it's any better. Stuart |
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| Author: | DavidL [ Wed Jul 21, 2010 3:04 pm ] |
| Post subject: | Re: Engine running too hot? |
Mine has now dropped from horizontal when the stats were brand new to half way between horizontal and the bottom line 2 years later. Spring has softened a little it seems. It does seem to get warm quickly however not so much standing but with low speed manuvering (like getting into the garage) the fans are on in no time but they do pull it back dwon quite quickly. Anyone else find that long uphills put the gauge up a few degrees and long downhills drop the gauge? |
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| Author: | J.J. [ Wed Jul 21, 2010 4:27 pm ] |
| Post subject: | Re: Engine running too hot? |
Scam 75. Mines a Porsche stat. So I think thats just how they are. It is working as the temp probe proved. Only way to get it cooler would be to put an old one in! Since they do fail that really isn't a good idea. |
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| Author: | doctor924 [ Wed Jul 21, 2010 7:09 pm ] |
| Post subject: | Re: Engine running too hot? |
Thanks for the all the replies - seems a common thing to watch on these cars - but glad to hear mine sounds reasonably normal.... |
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| Author: | 944BLOKE [ Thu Jul 22, 2010 9:38 pm ] |
| Post subject: | Re: Engine running too hot? |
Aha ! so its the thermostat is it? I ve had the same problems recently since having water pump, belts, tensioners and rollers AND new thermostat fitted.Its a bit scary when the needle gets over to the 3/4 mark before the fan comes on,but good to hear that its normal! 
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| Author: | scam75 [ Sat Jul 24, 2010 4:13 pm ] |
| Post subject: | Re: Engine running too hot? |
My temp readings seem to have settled down after 500 miles or so with the new stat. I am now running just below half way pretty much all the time. At a standstill in traffic it can get to just over half way then the fans kick in. On moving off it will go down to nearly the first line and then gently rise to just under half way again. I wouldn't be happy if I was touching the 2nd line very often and I'm starting to think I've had some air in the system which I've finally got rid of after several bleeds. Or else the new stat just needed to free off? Who knows, seems ok now! Stuart |
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