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Cooling issues maybe a combo of problems.

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1.3K views 8 replies 5 participants last post by  Silent  
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#1 ·
I bought my car 2 weeks ago and have been loving it, and besides a light leak from my rear main seal everything has been good to go. I was driving home last night at around 8pm on a fairly cool night and after about 5 minutes of driving my high temperature warning came on and I noticed that my gauge showed in the red. I pulled over on the freeway and let it cool, and I began searching the forums (everything from water pumps to thermostats...). I checked the overflow and expected it to be boiling and hissing at me... it was fairly cool and definitely not boiling. I let it rest for about 20 minutes and and cranked it back up thinking it might be a fluke, got about 2 miles and it was hot again. Pulled over, and I got a tow home.

I searched a lot last night and noticed that the most common failure for thermostats in our cars is an open failure. But I think mine has failed closed. The drivers radiator hose is hot to the touch while the passengers is not. My electronic fan is not activating, and my fan clutch is not engaging either. But, I think it all comes down to the thermostat. I don't think the fan is activating because the temp sensor on the passenger side hose is not getting warm radiator fluid to turn it on, does that sound right. And I don't think the fan clutch is engaging because there is not enough engine/radiator heat to activate it, does that sound right? Or is everything going to hell and I need to replace sensors, fan clutch, and t-stat?

Please help.

Thanks,
Ryan
 
Z
#3 ·
I have had a stuck-closed thermostat in the past. The symptoms do seem to match what I experienced in terms of overheating. When the car was moving, the temp needle stayed out of the red zone. When the car was stationary it quickly overheated. I don't recall what the situation was with the electrical fan.
 
6
#4 · (Edited)
Yes, sounds like the t/s is stuck closed, or at least almost closed. It appears to be allowing a trickle of hot water through to the rad which you can feel in the upper hose but that is quickly cooled as it flows across the rad so the bulk of the rad stays cool.

Another possibility is the metallic seal ring around the t/s piston has failed but that's rare.

And yet another possibility is a plugged rad but it would be strange for it to plug instantly like that, if you had no earlier history of temps creeping up.
 
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