Head gasket question

[Hopefiend]

I did the the glove test and found the driver side rear most cylinder to be pumping air into coolant system... pulled head and sure enough the gasket failed... i also noticed that there is a slight amount of milk inside the passenger side valve cover... can this be from moisture in the system from the one gasket i know is bad or is this indicative of a bad gasket on that side as well? It did not show anything on that side during glove test...

 

[JoshT]

Bad head gasket... If any coolant leaked into the crank case it's going to mix with the oil and show the symptom on either bank, as well as anywhere else in the system. If it's actually milkshake and not just condensation, it could be from the known bad gasket or it could be from the other one.

A compression test could tell you if that bank has a cylinder leak, but it wouldn't tell you anything about the oil passage to water jacket.

The only way to know for certain would be to pull that head and check, AKA play it safe and change that gasket too. Otherwise you could button it back up with the assumed good gasket and hope for the best, but if wrong that means redoing all the work to get to the head.

If it the gasket had never been replaced, or hadn't been replaced recently, I would probably do both while in there. A head gasket set is going to come with two head gaskets and the new head bolt set is going to have enough to do both heads, you'll have the parts even if you don;t use them. It's really only costing you a little extra time to pullthe head and clean the surface.

Now that is assuming that it is a head gasket. Has the engine ever been overheated? Those earlier Ford V6s were bad about cracking heads if they got too hot. About the same symptoms as a bad gasket. With the head off I'd give them a very thorough inspection for cracks. IIRC they usually show up around the valve seat and spark plug area. Might be worth while to have them professionally checked? The only one I've seen cracked was on a 4.0L and it was fairly obvious crack with the head off. I'd hate for you to go through the work of replacing the gasket and be reinstalling a cracked head.

FWIW, if this is the truck in your profile pic I'd take the time to do a little extra work. While the heads are off this would be an excellent and easy opportunity to replace your valve stem seals. At that age/mileage they are about due to start leaking, generally exhibited as bit of bluish smoke on cold startup. With the head off you can rent the valve spring compressor from the parts store and change them pretty quick. It would be better now than having to dig back in there to do it later.