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does this sound like a bad thermostat?

G

Guff55

New member
'98 Gran Prix GTP 3800-SC..127,000miles..when cranking cold it takes a while(several miles) to get up to 185/190 on the instrument guage but levels off there..after driving 20-25 miles and getting into several stoplights on a 95 degree day with the a/c on..guage will creep up 2-3 notches past 185 on guage(guessing around 195/200) then will go back down to 185/190 after a few minutes of unrestricted driving..Thanks-David
 
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No, mine and my brothers GP does the same thing. Sitting in traffic I always notice the gauge creep a bit until I get moving. Even with the A/C on (which automatically calls both fans ON) the temp is going to rise. I've got around 400K on my engine currently and it hasn't cooked itself yet. My 95 Bonneville with the same series II 3800 is at 312K and acts exactly the same.

If the coolant is old then I'd just flush the system and refill with standard green coolant and call it a day.
 
FordMan77 said:
No, mine and my brothers GP does the same thing. Sitting in traffic I always notice the gauge creep a bit until I get moving. Even with the A/C on (which automatically calls both fans ON) the temp is going to rise. I've got around 400K on my engine currently and it hasn't cooked itself yet. My 95 Bonneville with the same series II 3800 is at 312K and acts exactly the same.

If the coolant is old then I'd just flush the system and refill with standard green coolant and call it a day.
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thanks for the info..ditch the orange dex-cool and go with green?
 
Yep. Flush the entire system until it's clear (don't forget to clean out the overflow bottle). Once you get it clean, I usually just drain the radiator and refill that and the coolant bottle with green. Should be about the perfect mix of water/coolant. And do NOT buy the pre-mixed stuff or your water/coolant ratio will be off.

There are instruction on here on how to bleed the cooling system as well. Yes, there is a proceedure, lol..
 


Guff55 said:
thanks for the info..ditch the orange dex-cool and go with green?
Click to expand...


flush the hell out of it. I flushed water through one of the heater core hoses, then pulled tstat housing, flushed into engine, in rad hose there into rad, through filler neck, put tstat housing on without tstat, filled with water, ran for a while, flushed, refilled, ran, then final flush. my water pressure at hose sucks so it wasn't great but It cleared a lot of crap out.
 
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