HELP! Overheating problems


#1

I have a 1993 Mercury Cougar XR7 3.8 L V-6 with 138,000 miles that has been having overheating and coolant loss issues for the past 3 months. So far I have replaced the radiator (cracked), 2 thermostats (not opening), and the thermostat housing; which is where the mechanic said the leak was coming from. I don’t have a visible leak now but it is still overheating after about 15 mins of driving it. I took it back to the same mechanic who said the sealant on the head gasket needed to be replaced and that would cost $1400. As far as I know, there is no “sealant” ON the head gasket…the head gasket is the sealant. I took it to a different mechanic who said I have leaks in several of the coolant hoses and it will cost $350 to fix. I can smell antifreeze every time I get out of my car, but I don’t see any leaks. I am concerned I’ve blown the head gasket but the mechanic says they cannot test that until the hoses are fixed. Does this sound reliable? Could it be a hose issue and that’s all?


#2

A test for the headgasket can in fact be performed without the hoses. It’s simply a test wherein the spark plugs are removed, the crank turned until both of its valves are closed (it’s done one cylinder at a time), air is pumped into the cylinder and a valve closde off to seal the air in the cylinder, and the pressure is monitored for loss. Too much pressure loss means the cylinder is leaking. Bubbles migrating up and out the radiator cap hole are even more definitive.

However, if mechanic #2 can show you the leaks in the hoses that may be your problem. If these are the original 28 year old hoses, they may well be leaking. Hoses are easy to change yourself if you’re even minimally mechanically oriented and don;t mind dirty hands. Perhaps you should do that.


#3

If you smell the coolant that is good in that it is not putting head gaskets at the top of the list. same mb I think is on the right track. A simple pressure test will hopefully find the point of pressure loss.


#4

Thank you guys so much. I will talk to the mechanic and see if we can’t do a pressure test tomorrow.


#5

Have you checked the water pump for leaks?


#6

Could be lower intake gaskets. I have a Windstar with the same engine as this Cougar, and it would lose coolant over time, and I could smell it, but it wouldn’t end up on the ground and was very difficult to track down even with a pressure test. It was weeping out the lower intake gaskets. This is just a suggestion for where to look for a leak and is unlikely to cause overheating unless the leak is severe enough to run the vehicle out of coolant in short order. The water pump, as suggested by FordMan59, is more likely to cause overheating. Head gasket issues are also likely to cause overheating, and unfortunately the 3.8L engines of this era had head gasket problems.

How on Earth did you end up with two bad thermostats??? Did you test them to determine they were indeed defective? This is very peculiar.