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Overheating after turning off the engine

 
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exd  



Joined: 04 May 2008
Posts: 26
Location: Prague

PostPosted: Tue Oct 14, 2008 12:08 am    Post subject: Overheating after turning off the engine Reply with quote

I solve almost all problems with my 924 and this is the last one (I hope:) )..

After I turn off the engine, the temperature goes up and sometimes hits the read area. Then few litres of water runs out. It doesn't overheat while I'm driving, just after I stop. The fan is working. With ignition on, on high speed, with ignition off on low speed. But mostly max. 20 seconds after I turn the ignition off, no matter what the temperature is.
Today, when I got home, the temperature was high, fan was working, so I tried to leave the ignition on (with the engine not running), so the fan would run on high speed to cool better the engine. Even off that the teperature was growing up.

Does anyone had similar problem and could help me, please?
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Chrenan  



Joined: 15 Jan 2003
Posts: 3903
Location: Canada

PostPosted: Tue Oct 14, 2008 12:33 am    Post subject: Reply with quote

20 seconds doesn't seem long enough. Have you replaced the fan switch that screws into the radiator?
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1987 951 - M193 Version for Japan
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exd  



Joined: 04 May 2008
Posts: 26
Location: Prague

PostPosted: Tue Oct 14, 2008 12:41 am    Post subject: Reply with quote

no, not yet. What worries me is that the temperature is growing even with the fan running on full speed. I was thinking if the problem isn't anywhere else..
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Chrenan  



Joined: 15 Jan 2003
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Location: Canada

PostPosted: Tue Oct 14, 2008 12:46 am    Post subject: Reply with quote

Is the air bled from the system? Major air pockets can cause this type of heat soak after shutdown.
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exd  



Joined: 04 May 2008
Posts: 26
Location: Prague

PostPosted: Tue Oct 14, 2008 12:57 am    Post subject: Reply with quote

thanks Chrenan, that may be it. I will try to bleed it again..
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datatrain  



Joined: 15 Sep 2007
Posts: 441
Location: Osoyoos, British Columbia

PostPosted: Tue Oct 14, 2008 1:53 am    Post subject: CAP Reply with quote

Have you checked the radiator pressure cap ? Sounds as though it's not holding the pressure.
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dpw928  



Joined: 02 Nov 2002
Posts: 1860
Location: owasso, ok 74055

PostPosted: Tue Oct 14, 2008 5:30 am    Post subject: Re: CAP Reply with quote

datatrain wrote:
Have you checked the radiator pressure cap ? Sounds as though it's not holding the pressure.


+1

The pressure cap is there to keep the coolant from boiling by maintaining a pressure on the system. No or low pressure will cause the coolant to boil and overflow.

Dennis
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exd  



Joined: 04 May 2008
Posts: 26
Location: Prague

PostPosted: Tue Oct 14, 2008 6:42 am    Post subject: Reply with quote

stupid question, but how can I tell if the pressure cap is good? tomorrow I will try to bleed it and I will see..
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dpw928  



Joined: 02 Nov 2002
Posts: 1860
Location: owasso, ok 74055

PostPosted: Tue Oct 14, 2008 6:53 am    Post subject: Reply with quote

A lot of auto parts stores have pressure testers. A general test would be to check the rubber seal to make sure it isn't cracked/split etc., then compress the spring to see if it takes about the same pressure as indicated on top of the cap. If it is old and you are unsure, buy a replacement.

Dennis
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Ozzie  



Joined: 12 Mar 2005
Posts: 4448
Location: Townsville, Qld. Australia

PostPosted: Tue Oct 14, 2008 8:39 am    Post subject: Reply with quote

Bleed, bleed and more bleed.
If you dont have the bleed plug in the rad hose then have the car facing uphill and bleed.
The temp will rise after shutdown but if it that hot that it is boiling change the rad cap if it continues.
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Martijnus  



Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands

PostPosted: Tue Oct 14, 2008 9:12 am    Post subject: Reply with quote

just for the record...
what's the right way to fill a completely drained coolant system?
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StienbargerR  



Joined: 28 Oct 2005
Posts: 1362
Location: Richmond, IN

PostPosted: Tue Oct 14, 2008 11:24 am    Post subject: Reply with quote

Make sure your fan in blowing the right way. I didnt realize it, but I had my fan wired backwards... it was making the car run hot, especially after I turned it off. My mechanics caught it luckily though!

Ryan
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1978 924 NA
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exd  



Joined: 04 May 2008
Posts: 26
Location: Prague

PostPosted: Tue Oct 14, 2008 11:49 pm    Post subject: Reply with quote

I bought new pressure cup, and I hope that it is fixed. I didn't have much time to test it, but it seems ok now (and the old one was pretty bad).

thank you all very much,

Erik
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