Started happening November and the problem is the same routine. Let it warm up for 10 min and it stays very cold, the needle doesn't move. But if you drive it it always runs kinda near the red every time I pass near my gas station LOL which is about a mile or two. Then it drops back to 185. But every 5 min it plays games with your head it goes a little past the middle mark which I think is 210- 220. And once every hour of driving it goes a little more and if you put on the Defroster or heat bam it drops to 185 in seconds and works sometimes for a little while it just delays the problem but still does it!!!!!!! If you let it idle it runs good around 185F 195F.

Maybe,

1.) thermostat

2.) Water pump, I notice sometimes when I DON'T put in OVERDRIVE it runs alittle cooler sometimes.

3.) HEAD GASKET, has 178,000 miles

Notes: I don't loose coolant. Doesn't burn oil, it leaks oil near the oil filter and I loose a quart every month. I always change the oil, don't beat on it, fan works, radiator looks good, hoses are good.

 

I guess I will start with a thermostat , have low money this winter so im going to start cheap. Thank god its not like my LT1 LOL.

1.)What is the right / best procedure for doing the thermostat and coolant flush.

2.) Whats better the Duralast or stant gasket. Can I use the felpro gasket on either one. The thermostats are 8 bucks but each one seems to vary on weight.

 

My truck has always done the same thing until I put a new thermostat in, now it gets up to 185 and stays right there.