2001 Monte Carlo SS.

I recently had the radiator replaced in my '01 SS as it had a leak in the top of the radiator. After purging the air from the system it doesn't appear to be leaking but it overheats when idling. It will sometimes rise past the half way mark (over 200º) when idling? It typically will go back down to the 180º- 185º mark when driving. I'm wondering if its a thermostat issue or the fans? I bought a cheap thermostat from Autozone to replace the old one about a year ago and I'm reading the reviews on their site which aren't good. I also haven't actually seen both fans running on this.

To trouble shoot the fans if I turn on the A/C are both fans supposed to turn on? Thanks for any tips or tricks. I can replace the thermostat as I can get an AC/Delco on Ebay for like $13 bucks shipped so I'm not concerned with throwing parts at it. But just wondering what you guys might conclude or have tried.

 

OK so this is confusing me now. I just drove home and the temp gauge was approaching the 200º mark. So I threw on the A/C and noted that both fans are spinning when I parked. I shut the car off and decided to try the bleeder valve and a WHOLE bunch of air came out. Now I had bled this after the radiator replacement like 5 times until I got coolant to stream out and everything seemed fine after that. Is it possible there was STILL an air pocked trapped somewhere in the system? It should be noted that I am not losing coolant and the radiator is full.

 

It is possible that there was still air trapped in there. When you tried bleeding it before, was your engine hot??
It can take numerous times to get all the air pockets out.

 

I agree with P343. I've had to bleed my gen 6s several times after cooling system repairs. Also, I know it's tempting, but avoid opening the radiator cap if you can. That can let air in when the car is running.

 

The engine needs to be at operating temp(or close to it) for the bleeding procedure to be most effective. Then you still might have to do it numerous times. Keep shop rags near the valve to catch any coolant that may come out. But I am sure you know that

 

Also, how hot are you talking when you're saying its overheating? It is normal for the engine temp to rise when standing still. The fans are set to come on at 220 And yes i believe both fans should come on when the a/c is on.

 

Leprechaun is correct. Both fans will turn on in AC mode under any condition regardless of engine temp.
The question is, are they coming on w/o the AC on. They should both come on if ECT is high enough, or not at all when cool enough. If only one comes on there's a problem. May need to check grounds, fuses, fan relays (3), and/or fan motors and connectors if they don't run when commanded by the PCM.

 

Thanks guys I think opening the radiator cap was my error....

It never really crept over the 200º mark until AFTER I opened the cap to make sure it wasn't low LOL. I thought I read somewhere once you do that it introduces air into the system so I may have caused the air pocket myself. I think its properly bled now so I'll see what happens with it when I drive it again. Oh and YES both fans run when the A/C is on. The only thing I'm not sure of is if they both come on without the A/C on. What is ECT? Is that engine coolant temperature?

 

Yup, you got the ECT right.

You can check the fans by starting the car with the AC off and let it idle. Both fans should come on after it warms up to just past normal operating temp which is straight up on the dash temp. gauge. Both fans should run for a while (5 minutes), then both shutoff when the temp. gauge drops just below normal operating temp. The process will repeat as temp. go up and down. They will stay on longer if your driving because there's a load on the engine and higher RPMs. They also have a low and high speed, but you probably won't notice high speed without a scan tool to monitor and/or command with, or somebody riding under the hood while going down the highway at 60+ on a hot day with the AC on. I would not recommend that LOL.

Hopefully you're good to go with the bleed, but feel free to check back if you're still having problems.