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Old 01-11-2017, 11:05 AM   #1
fanofe30s
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Is just under the 1st mark on the cluster too cold?

Hi r3v

Recently I changed my timing belt, and figured I'd replace the radiator along with all of the coolant hoses. I ended up upgrading to a z3m radiator and with the 75 degree Celsius thermostat (I live in the desert) that I had previously, it ran in between the blue and the 1st mark... definitely too cold. I've since put in the proper 80 degree thermostat, but now it sits 3/4ths of a needle's width under the 1st mark on the highway, and just past the needle when idling for a while.

For reference, with the 75 degree thermostat and stock e30 radiator, I've always run around the 1st mark.

Obviously it's January, and it's also possible that the cluster gauge itself is not 100% accurate, but is it worth keeping this thermostat? Or is it worth using a cheap 82 degree thermostat from somewhere like autozone to bring it up just a little bit more? I'm worried about quality and making it too warm.

I don't mind investing in an IR gun to take more accurate temperature measurements, but where? And what would the proper operating temperature for these measurements?

Thanks
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Old 01-11-2017, 12:35 PM   #2
dnguyen1963
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With a properly operated 80C t-stat, the temp should approach the middle of the gauge after 15 min of driving even in the upper midwest winter. I would get an IR gun and measure the temp at the thermostat housing (the side toward the radiator), upper radiator, and lower radiator. Measure the temp when you start the car until warm-up. The t-stat housing should stay cold until the t-stat opens at 80C. If your t-stat is stuck open, the housing would have trouble getting up to 80C. You should verify that the t-stat is working properly by submerging it into a pan of water and heat it up to boiling. t-stat should open when temp reaches 80C.
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Old 01-11-2017, 10:09 PM   #3
Das Delfin
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mine is always at just under first mark in the winter and at half way in the summer. If I let it idle at a drive thru window it goes to the half way. Doesn't ever go to 3/4
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Old 01-12-2017, 05:54 AM   #4
Kershaw
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Mine always sits in the middle, regardless of outside temp. Could be 95 or 5 degrees.

The gauge is old and who knows what resistance it's reading nowadays.
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Old 01-12-2017, 03:49 PM   #5
digger
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Quote:
Originally Posted by dnguyen1963 View Post
With a properly operated 80C t-stat, the temp should approach the middle of the gauge after 15 min of driving even in the upper midwest winter. I would get an IR gun and measure the temp at the thermostat housing (the side toward the radiator), upper radiator, and lower radiator. Measure the temp when you start the car until warm-up. The t-stat housing should stay cold until the t-stat opens at 80C. If your t-stat is stuck open, the housing would have trouble getting up to 80C. You should verify that the t-stat is working properly by submerging it into a pan of water and heat it up to boiling. t-stat should open when temp reaches 80C.
mine would be ~95C in the middle, at the tick to left of middle mine is ~80C, less is dont trust the gauge too much
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Last edited by digger; 01-12-2017 at 04:58 PM.
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