Engine temp isnt rising

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85K304SPD

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I know its frustrating not to know why, but it is a good problem that it is not getting too hot. Maybe the intake change made a difference. The stock big block 402 in my GMC only gets to the first mark on the temp gauge under normal driving with a 195 thermostat.
 

79Sea30

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Is the stat stuck open?

I know its frustrating not to know why, but it is a good problem that it is not getting too hot. Maybe the intake change made a difference. The stock big block 402 in my GMC only gets to the first mark on the temp gauge under normal driving with a 195 thermostat.
You're not the first person to say that to me honestly. For sure maybe it's running cooler now. I also realized when re-timing that the original was way out, so now within spec maybe it's running a bit cooler like it should.

Anyways, thank you all. Love this site, and appreciate all the insight.

Kyle
 

Hunter79764

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Do you have a temp gun to verify anything? I wouldn't trust it entirely, but if you're seeing 188° or something out of the water neck after warm up your Tstat is working, then if you see appropriate temperatures around the temp sensor, I'd think you might have a gauge issue. If you have 140° max coming out of the water neck, I'd assume something is causing the T-stat to stick open or something.
Not knowing your setup, my first thought was that changing the intake caused you to lose a temp sensor ground, and it "floating the ground" would cause bad readings. If your sensor is in the head and didn't change, that seems to rule that out, but I'd probably still at least temporarily run wire from the ground post to the intake, intake to block, block to chassis, etc., pretty much touch it to everything you can and see if the gauge behavior changes.
 

79Sea30

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Do you have a temp gun to verify anything? I wouldn't trust it entirely, but if you're seeing 188° or something out of the water neck after warm up your Tstat is working, then if you see appropriate temperatures around the temp sensor, I'd think you might have a gauge issue. If you have 140° max coming out of the water neck, I'd assume something is causing the T-stat to stick open or something.
Not knowing your setup, my first thought was that changing the intake caused you to lose a temp sensor ground, and it "floating the ground" would cause bad readings. If your sensor is in the head and didn't change, that seems to rule that out, but I'd probably still at least temporarily run wire from the ground post to the intake, intake to block, block to chassis, etc., pretty much touch it to everything you can and see if the gauge behavior changes.
Thats a great idea honestly. And no I didn’t have an infrared. I grabbed one tonight to do that test. Hoping to flush tomorrow evening and reinstall everything and re check it. Going to do some more digging.

Thanks
 

Hunter79764

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HF temp guns are worth all the pennies spent on one...
Good luck on it.
 

79Sea30

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Just a quick report. Drove it for quite a while yesterday. No issues with overheating and heat was cranking. Gauge now reads where it did prior to installs.
 

79Sea30

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Afternoon All-

Quick update, after a few weeks of driving. She's driving great, and no issues with temps. Dialed in to the same hash mark as it was prior to the intake swap etc. I think it was a few things but the last air bleed from the coolant, there was tons of air that came out. Wondering if that was partially what I saw issues on. Either way, happy driving. Now back to listening to those good old flowmaster 40's installed last weekend :)

Thanks again for all the help and support.
 

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