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1992 seville overheating

07-31-2007, 02:51 PM
My coolant keep bucking up to the resevoir, everytime the car start to get hot. I replaced the water pump 2 years ago, also the thermostat recently but still having same problem. Why would the coolant back up to the reservoir? No leak any where at all. why would the car do this? Pls help thank in advance.

07-31-2007, 05:33 PM
I had the same problem on my '94 Deville. And what had happened was the coolant over flow tube, (the one that goes from the radiator cap to the reservoir) was clogged up. Once that was cleared, it worked fine. Also check the radiator cap to make sure it is in good shape and not plugged up as well.

08-01-2007, 10:04 AM
Thanks for the reply. I tried cleaning the radiator cap and over flow tube. still having same problem. If i leave the radiator cap open while the egine is running the coolant will come out from the radiator. When I place the cap back it will back up on the resevoir and will overflow on the bottle. I have to turn off the egine so I would not loose all the coolant overflowing on the resevoir. The radiator fan start on 220 degrees. It seem like the hot coolant is not cycling round to get cool. One the thing I observed is that the upper hose is not getting warm when I touch it after the fan ran. Temp just keep going up till it show a message on the dash (idle engine, engine to hot).

08-01-2007, 09:54 PM
If the upper hose isn't getting warm, then the thermostat is stuck closed not allowing any coolant to get through. It'd take the thermostat out, test it, and if it doesn't open at the temp it should (195 degrees I believe), then replace it.

08-02-2007, 11:51 AM
I bought a new thermostat and still having same problem. I check if the bottom hose is pinch but it is not... I red on the manual one the reason coolant is overflow on the bottle is loosing system pressure. That this mean I need to buy a new radiator cap? Or there something else that causing this?

08-02-2007, 07:23 PM
Yes, a bad radiator cap would cause the coolant to overflow. They are cheap, so it's worth the try!

08-06-2007, 10:05 PM
reservoir over flow fixed. Bad radiator cap, I tried to run the car with water on the radiator just to make sure that the coolant won't overflow again. And it did not, but the temperature gone up to 250f. then it went down to 244f. coollant seems to be cycling around the egine better cost the upper radiator host gets hot. If I used the coolant you think I get same result on the temperature? thanks!

08-09-2007, 11:17 AM
I fill the radiator with a fresh coolant but still over heating. I turn the heater on cold air coming out. then I hear a clicking sound on the upper radiator hose when the temp get to 250F. pls help...

08-10-2007, 07:44 AM
Two things come to mind. The first is that there was air in the system and the coolant level was low. Did you run it with the cap off for a while to make sure it was full?
The second thing is that the new thermostat may be defective. What brand did you use and are you sure you installed it facing in the right direction?

08-10-2007, 11:16 AM
Thanks again for your response... I did not run it with radiator cap open. I would try that. And what brand of thermostat is wright for seville? What is the right way to install thersmotat? I install the thermostat the way it showed on the shop manual. I also turned the heater, but only cold air coming out even the temp was on 250F.

08-14-2007, 11:26 AM
Sorry for the delay in responding. Personally, I'd only use an OEM stat or one made by Stant. It does sound like you installed it right if you followed the manual.

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