Overheating while A/C is on

LINCLS00

MEMBER
2000 LINCOLN LS
3.9L
V8
AUTOMATIC
135,268 MILES

I’ve previously had problems with my car overheating. It just had work done to replace the lower radiator hose that had a leak in it and the thermostat got a new bleeder cap. Now I’m having overheating problems again. It was running fine for an hour and got stuck in stop and go traffic. The A/C was running and it started to overheat. I turned the heat on and cranked it up to 90 degrees but it wasn’t pushing out any hot air, so I pulled over and turned off the engine. It started to cool down so I started it back up and turned the AC/heat off and it cooled back down. There’s no leaks and the reservoir is completely full.

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

This sounds to me like you could have an air pocket in your cooling system that is not allowing the coolant to flow. The reason I'm thinking this is because when you turned your heater on, you had no heat. Also, you had a bleeder drilled into your thermostat so you should have coolant flowing a little bit at all times so some heat should have come out. In order to get all the air out of your vehicle's cooling system, it needs to be filled from the highest point in the cooling system. How I fill my vehicle's cooling system is to unclamp the upper radiator hose at the engine. I lift the hose up in the air and pour my coolant into the hose until it runs out of the engine where the upper radiator hose attaches to it. I then put the upper radiator hose back to where it attaches to the engine and clamp it. Your cooling system should have no air pockets in it. Try this after draining your cooling system first and get back to us with what you are able to find out, please.

Thanks,
Alex
2CarPros