How can I test to see if My head gaskets are leaking on my 1995 FOrd F-150 4x4, 5.0L. I never have any coolant drip out of it, I dont see any leaks, and I dont have any steam coming from the tailpipe, but my coolant keeps dissapearing. I havent been checking it regularly, but i know i changed my thermostat a few weeks ago and flushed and filled the system, and now the resivoir is bone dry, and the radiator is low enough that I cant see the level of the coolant when i look down into it. Its been like this since I have owned it, THe coolant in the resivoir is usually brown and when i fill the resivoir up, it dissapears very quickly, but there is nothing leaking out onto the ground, and no smell of coolant burning off the block. When i changed the thermostat, i flushed out the system because all the coolant was brown, is that a sign of exhaust gasses seeping through the head gasket and contaminating the coolant? How can I be sure if the head gaskets are the problem, and could this be the reason the truck seems to have almost no horsepower in hot or humid weather? Any help is appreciated. Thank you.
-John

 

One suggestion I can make is to remove all your spark plugs and take a look at each one to see if anyone of them is really "white" that can be a sign of a head gasket. If you dont see steam out the tail and she is not overheating or boiling out the overflow it is unlikely that a head gasket is gone. But even a small leak can be hard to detect unless you can get to a garage and have them test the coolant for "carbon monoxide."

 

I would suspect a bad radiator cap. Since a cap that will not keep the correct pressure can leak vapor. I am unfamiliar with your truck set-up so I may be wrong.

Brown coolant is usually the sign of a lot of rust in the system. If you had a blown head gasket, oil usually starts showing up in the cooling system - and it ain't pretty. You could also do a compression check of the cylinders. That is not hard to do and since the previous post recommended checking your plugs, that would be a great time to do it.

Hot and humid weather = loss of power. Does that also mean overheating in your case?