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Discussion Starter · #1 ·
Ok...so from searching/reading other posts I think I have a bad coolant temp sensor...but I'll run it by everyone anyway.

Just picked up a 95 9c1. Drove it 100 miles home today and the temp gauge pretty much remained pegged on cold. In traffic it would move up a little, maybe 1/4 the way at most....but then once I got moving again, pegged on cold.

Towards the end of the 100 mile drive I had the check engine light come on. Once I got home turned the car off, then back on, check engine light went off.

At first I thought it was a bad thermostat (failed and in the open position)...however after reading posts and seeing the CEL I assume I'm looking at a temp sensor??
 

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Discussion Starter · #2 ·
Ok...after searching more I realize that the gauge temp sender is mounted in the passenger side head. So I'll look to replace that sender.

If the head sensor is bad will it throw the check engine light? Or is this only the PCM sender in the water pump??

Thanks!
 

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If the head sensor is bad will it throw the check engine light? Or is this only the PCM sender in the water pump??
The sensor in the cylinder head is for the gauge only. It will not trigger a CEL. You'll have to get the codes pulled to see what triggered the CEL.
 

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Actually the problem is the gauge itself. The temperature gauge is a weak point in the Caprice digital cluster. I've had that gauge go out in previous cars I've owned as when i change the head temperature sender or put in the dual output water pump temperature sender it did not fix the gauge reading, however when I upgraded to the Z28 cluster it did fix that problem. - Peter
 

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Discussion Starter · #5 ·
What are the symptoms of a bad thermostat?

Today I just started the car and let it idle up to temp. The hoses/radiator seemed to heat up slowly rather than remain cold and get hot once the thermo opens.

I'm not sure what temp the stock gauge starts at...but while idling for 15-20mins I got it about 2/3's the way up...it took a while to get there though. On the highway it remains right around the cold mark...
 

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What are the symptoms of a bad thermostat?

Today I just started the car and let it idle up to temp. The hoses/radiator seemed to heat up slowly rather than remain cold and get hot once the thermo opens.

I'm not sure what temp the stock gauge starts at...but while idling for 15-20mins I got it about 2/3's the way up...it took a while to get there though. On the highway it remains right around the cold mark...

Your thermostat may be stuck open. It would cause something like this. It would keep the temperature super cool while driving since it would be stuck open the whole time. It would take longer for the car to warm up since it's already open and allowing the coolant to flow through the radiator. If it was stuck closed, you car would run hot while driving because it wouldn't allow the coolant to flow through the radiator. They are very easy to change out. Replace it with a new LT1 specific thermostat and lets us know if anything changed.
 

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Discussion Starter · #7 ·
Well thermostat seemed to be ok...I haven't thrown it in boiling water yet.

However, it was a 160 degree and not an LT1 thermo...at least I don't think it was...it didn't extend down into the housing.

So I guess it's either the sender or the cluster...thanks for all the replies.
 

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Discussion Starter · #9 ·
Yeah I put in an LT1 180 from the stealership.
 
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