No heat! 01 GP SE

so needless to say, my 2001 SE is having some issues with the heat. Coming into a new england winter, this is problematic :icon16: the coolant levels are alright, I checked that, and no CEL (or SES if you prefer). Basically if I put the heat at max, and crank up the fan (bad resistor, only works on 5 lol) I dont get any heat until it idles for 15-20 minutes, and once I start driving it goes bye bye.

now heres the weird part....

If I peg the gas and keep the rpms above 2000-2500, I get heat. not super heat but certainly acceptable heat. I let off the gas, the heat goes bye bye again. This makes for some COLD commutes to work if I dont keep it in 2nd gear on back roads to keep the rps up ;)

anythoughts how to trouble shoot?

so needless to say, my 2001 SE is having some issues with the heat. Coming into a new england winter, this is problematic :icon16: the coolant levels are alright, I checked that, and no CEL (or SES if you prefer). Basically if I put the heat at max, and crank up the fan (bad resistor, only works on 5 lol) I dont get any heat until it idles for 15-20 minutes, and once I start driving it goes bye bye.

now heres the weird part....

If I peg the gas and keep the rpms above 2000-2500, I get heat. not super heat but certainly acceptable heat. I let off the gas, the heat goes bye bye again. This makes for some COLD commutes to work if I dont keep it in 2nd gear on back roads to keep the rps up ;)

anythoughts how to trouble shoot?

Thermostat stuck open. Had the same problem on a Grand Am. Replace with a new one and you're good to go less than $10.

try the T-stat, also check the cooling system for air pockets. if it doesnt help...I'm afraid to tell you it may be the head gasket (if you have the 3100 in your SE)

I agree, start simple. Replace the t-stat. How many miles are on your GP? Is it a 3100 or 3800?

on another note...if its the 3800, its most likely the UIM and LIM that need to be replaced.

Hey guys I recall the 2000 and up SE models only came with the 3100 V6 VIN "J".

its a 3100, BNaylor is correct :) its got like 126k miles on it at the moment. for 10 bucks ill replace the thing ANYWAY, cheapest option to try. but....

I just went out and looked with a flashlight... follow the top radiator hose to just underneath the throttle body. the hose connects to a cast pipe about 4-5" long, with a brass bleeder on it, and is bolted to the motor directly beneath the throttle body.

please dont tell me thats where it is, its going to be a PITA to get to ><

yep, you found it. I usually just remove the throttle body when I change them. Plus its a good time to clean the carbon out of the t-body.

Just take off the accellerator/cruise cables, and the two 10mm bolts and 1 nut, set the cables and bracket aside. Then take off the throttle body bolts and slip the t-body out of there. If I remember right, there is another nut on the coolant bypass line securing it to the t-body. Once they are all off, the t-body should just slip off after you disconnect the coolant lines. Then the t-stat should be really easy to get to with a 13mm wrench. Dont forget to remove all the old t-body gasket and install a new one.

Also, just to point out concerning the two bolts for the thermostat housing. One of the thermostat housing bolt holes is slotted so you do not need to remove one of the bolts completely. I think it is the bottom one. The exhaust crossover is limiting clearance which is why removing the throttle body is the best option on the GM 3100/3400 engines.