I have no heat, but the engine is overheating.

[staticwarp]

hi there,

a few days ago i noticed the thermostat in my 97 aerostar was all the way in the red zone. i think i have a slow coolant leak as this happens every so often and i have to top it off. when i filled it up, it drank a half bottle of coolant and a full bottle of water, as i didnt have any other coolant handy. i have done this before and havent noticed any problems. however, about four days later (today), i noticed the thermostat creeping back over to the hot side and eventually into the red. this is on my daily commute to work which is about 15 minutes thru city traffic (35-45 mph, stop lights, etc).

now usually when it starts to overheat i can switch the dashboard temp controls to hot and vent, which will heat the van up to a miserable degree as my power windows dont work, but lets the engine cool off enough so the temp gauge isnt in the red and i can get where i'm going and let the thing cool down.

today when i tried this, the temp gauge stayed in the red and all i'm getting is cold air from the vents. the air is as cold as when the ac is running full blast, even though the engine is supposedly overheating.

so, to sum it up, i've got no heat and the thermostat is telling me the engine is overheating. any ideas as to what i can do to fix this?

thanks!

edit: before heading home from work i topped off the coolant again. it seems my slow leak is not so slow anymore as it drank half a bottle of water again. the heat works and its not overheating. what does it take to fix a coolant leak?

 

[BrooklynBay]

Welcome to this forum! Go to Autozone, and get a cooling system pressure tester from their tool loaning program. It will help you find the location of the leak.

 

[JayT]

I have the same year Aerostar, and the problem is that you need to burp the cooling system when you refill it. Top it off when it is cold. Start it and run it until the thermostat opens. When it opens you will get a bunch of bubbles, and then it will vomit out about a quart of coolant, and go way down. Then add coolant till it comes back up to the top again. Squeeze the bubbles out of the upper radiator house. Wait for the thermostat to open again and repeat. Check it again the next day and top it off. If you are still not getting heat, replace the heater control valve. It's a cheap looking plastic device on the left about 6-8" and at 11 oclock from the air cleaner.