at 177k, my 5.4L is getting smelly under the hood. I can only best describe the smell as similar to a time I drank too many beers and peed on a campfire. Ugggh. I did see a only few drops of something wet (coolant?) apparently coming from the right side head on to the right side exhaust manifold. Engine seems to be running fine. Suppose this means a head gasket R&R ? How else can I verify before tearing it apart?

 

Some symptoms of a bad head gasket:
White smoke out the tailpipe usually sweet smelling.
Pressurizing of the coolant system especially the degas bottle and upper radiator hose.
Coolant or oil leaking from between the cyl head and block.
Hotter than normal hot air from the heater and temperature gauge spikes and then drops.
One way to determine a blown gasket is to either have a Hydrocarbon test performed on the cooling system or rent/buy a kit from someplace like Napa, Auto Zone,etc. If Hydrocarbons are present its pretty safe to say that your head gasket is leaking at least between the combustion chamber and the coolant passage. Good luck.

 

If you see coolant coming out of places it shouldn't on the actual engine, then head gasket or intake gasket failure is probably the cause. Or someone has been pissing on your engine.

 

I had the same problem...external head gasket leak. Problem solved...dropping fresh 4.6 in.