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Discussion Starter · #1 ·
I've searched many, many posts but I can't see the exact symptoms I have. It appears to be a thermostat problem (I hope). I know you've seen this befoe but I appreciate your ideas.

Car starts, runs normal. Temperature guage generally rises normally when car was cold -- gets no further than 1/3 way up upon warmup. It then drops until completely bottomed out over the next 5-10 minutes.

The worst part (one that I don't hear people talking about) is that the interior cabin heat dissapears after the guage drops. This weekend, I had to drive 12 hours in single digit to teen temperatures and I was so cold that long underwear, two layers of thick socks, hand warmers stuffed in my shoes and two layers of gloves could not get me more than two hours on the road. I couldn't feel my feet. Awful.

The only thing that kept me going (for a while) was the seat warmer. My backside was completely comfortable while my feet were numb. Before I could never figure out why anyone would use the highest setting on the warmer until I experienced that.
 

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Definitely your thermostat.
 

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To get the temp guage to read normally after it bottoms out....usually you just have to pull over, shut the car off. Then restart, the guage should go up to normal operating temp.

The solution on this issue for me, was to have the thermostat replaced (it actually packed it in and remained closed while driving to work one morning). Luckily, i pass right by my local saab indie and dropped off my car. He replaced the thermostat and the temp guage has never bottomed out since and the car warms up within a few minutes.

Hope this answers your question.
 

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Ah, good point. These cars shut the Heater Bypass Valve when the engine is cold to promote engine warm-up, that's why your not getting heat. I'm not sure if the temp sensor and the thermostat are a package though, that will take some investigating.
 

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I can not remember who posted the explanation for the temp guage reaction when the engine does not warm up fast enough. It basically said that the engine had a certain amount of time to reach normal operating temp, if it doesn't meet that requirement, the temp guage drops to signify a problem. And i believe it said that it does not throw a cel either.

It's possible that the bypass valve is also controlled by this programming, as you suggested.
 

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Discussion Starter · #6 ·
thanks...

Thanks guys. My past experience with bad thermostat was that the engine would overheat. That's why I was so confused about this situation.

Also, pulling overl, shutting off and restarting doesn't reset it for me. It will briefly raise just a tad for a quick shutoff but will only go up of any significance if I leave it off for quite a while (not practical on the highway...)

PL
 

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The stat is stuck open hence long warming up time and little/no heat, just change it out to get your feet nice and toasty again. :p
 

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Thermostat sounds about right.... I am putting in a new one this weekend along with a new upper radiator hose.
 
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