87 Buick century overheating

I have an 87 buick century custom thats overheating.

I changed the thermostat 2 months ago...worked fine.

About a week ago it started overheating again.....the fan was kicking in but too late. So we changed the little thing that sends the signal for the fan to start.
Now there seems to be a small leak by the back of the engine (no where near the radiator or the little antifreeze tank) that smeels like antifreeze AND its overheating.

What could it be? :banghead:

Welcome to AF!! Where exactly is the coolant coming from. If it is coming from the firewall area near the belt end of the engine you may have a bad heater core that is leaking and you are losing coolant. If that is where it is coming from they are not hard to change and are not very expensive either. If it is coming from somewhere else once you find where it is coming from post again and we will help you determine what is going on.

Hmmm, you seem to have ruled out the t-stat, however there is a chance that they gave you the wrong one(temp wise) or that the one you got was bad before you put it in...so it might a cheap re-check to change it again. The only other thing I can think is that your water pump is failing internally and the coolant is not circulating. As far as the coolant leak...just about every engine that GM built has had intake and water pump issues. I've owned two and so far its par for the course. One had a bad intake gasket and H20 pump, and the one I have now has a seeping intake also. You didn't mention the engine size but I know the 3.1 & 3.4's are especially good for that. Just a couple things to look for. Let us know what turns up. M. :2cents:

What engine do you have?
Beside the leak how low on coolant?
Century's this old can get their radiators plugged up. Time for a new one.

Flush the cooling system
Check the heater core hoses and core itself
check to see if the water pump has failed internally
and they do sell bad T stats unintentionally
I love to diagnose cooling systems because of the fact that theres so much that can be wrong with them.

Thank you so much for the replies. Believe it or not I just checked them do to alot of things going on.....LOL!

Anyway...we replaced the heater core and it seemed to do the trick. It was a hose connected to the heater core that was the problem but to get to it the mechanic accidentally damaged the heater core so he had to replace it. It was hard to get to.

Thanks again!