atikovi

Not an F150 but '96 Mustang with the same engine. Car has 135K miles. Bad news is I can smell that maple syrup aroma from the exhaust that most cars with blown HG’s have. Have to top up with coolant regularly but don’t see any leaks on the ground. Idles a little rough. Put out some white smoke for a minute after starting after not having been driven 4 months. Good news is no water in the oil or vice versa. Temp gauge on the highway at 1/4. Even in town stop and go driving at 85F for over 20 minutes and the gauge is steady at the half way point. Are these engines prone to HG problems? Could it be an intake manifold leak? Would a compression test tell me anything conclusive if it runs fine otherwise?

2003XLT

USUALLY a dead give away is milky oil and white smoke and the smell of coolant coming from the tail pipe.

biglee88

Kinda sounds like it could be leakin between a water jacket and the cylinder but I'd run it and get it really good and hot and then park it and let it sit over night and pull the plugs lookin for moisture and smelling for coolant

udderbrudder

A foolproof way to be sure is with a c02 detection tester. I bought mine from Snap-On for about $70. If you have co2 in your cooling system you have a blown HG or cracked head. Period!!!!