I noticed a small amount of what appeared to be antifreeze where my truck was parked in the garage and figured it must have come from a joint in the exhaust system upstream of the cat converter. I did a pressure test of the cooling system with these results: The gauge dropped a very small amount during the test. That drop could be in the test equipment or the system. I then left the test equipment installed, pumped it up to 16psi and started the engine and let it reach operating temp. The pressure did not increase nor did the gauge fluctuate. According to the instructions with the test equipment, the pressure would increase if the head gaskets were bad and the gauge would fluctuate if it were a compression or combustion leak. And yes the coolant level was low, but it is NINE years old and has never had any added. Ok, I know it should be changed. NO THE TRUCK DOES NOT RUN HOT. And no white smoke from the exhaust. I don’t see any leaks except what I mentioned above. Connected my Scan Buddy tool and it showed NO codes.
Would appreciate any suggestions.

 

Is your truck a 99 model?

 

It is a 2001 V6 4.2L

 

The 97s and 98s were known to have faulty lower intake gaskets and timing cover gaskets.Any build date after 1/15/98 had the "newer revised" lower intake gaskets and May 97 the same with the timing cover gasket.I have seen several 99-01 4.2 engines lower intake gaskets fail.Yes,its rare,but has happened.
If it were my truck I would start with a dye test.NAPA sells a dye you can pour into your coolant system,run it for about a day,then look for any leaks with a black light.