Solved How did coolant get there?

[Raptor_]

2005 4.6L V8 Around 205k miles

It had been a very wet week here, and I was exiting the car wash when I started to get that familiar misfire shudder. After driving various vehicles with this engine over the past 15 years or so, I knew that COPs often failed in damp weather or after a wash when water would get in the spark plug well and short the coil, so I figured that's what it was, and I happened to have a spare in my closet at home, so no biggie. I waited for the code, saw it was #8 (rear plug on driver's side), then went to check it out. Everything looked pretty dry up top. I pulled the COP, and sure enough it was wet at the bottom... but it was wet with coolant! Sopped up what I could with a piece of paper shop towel and installed the other coil and everything's working as it should, but I can't figure out where the coolant would have come from.

Every now and then, I'll get a faint whiff of coolant, but the level isn't dropping noticeably, there's no steam, and I can't see anything anywhere else. Most of the cooling connections and junctions that I know of are either on the other side, or at the front of the engine, so how did coolant get into the #8 plug well? Any ideas as to where I should look for the leak?

 

[Raptor_]

Nobody has any ideas?

 

[BrooklynBay]

Connect a cooling system pressure tester.

 

[massacre]

Intake manifold gasket leaking coolant into plug wells is very common for 4.6L sohc

 

[Raptor_]

Intake manifold gasket leaking coolant into plug wells is very common for 4.6L sohc

I was under the impression that the only coolant in the intake manifold was in the crossover pipe (the one that used to crack before the 2001 MY update) between #1 & #5?

 

[massacre]

Is there a nipple on the intake for the heater core supply at the rear? IIRC that nipple was plastic, and cracks.

Also if you look at the intake and gaskets, it seems that there are coolant ports at the front and rear of the intake manifold. The one by #8 is blocked off though but there is a gasket there and that could be leaking.

 

[davidmmm69]

Intake manifold gasket leaking coolant into plug wells that is where mine has been leaking from for 2 years now... one more winter is what I want out of the truck... was going to swap the intake this fall but if its only leaking a very little then I dont think it is worth it. I pull the plugs and coils every other month to combat the leak and I only drive the truck maybe one week a month.

 

[massacre]

You can clearly see that there are coolant ports at both the front and the rear of the head.

 

[Raptor_]

Thanks for the info. Now I've got another place to look.

 

[Raptor_]

BTW, just wanted to give an update - It was in fact the intake manifold that was causing the problem. I had my mechanic do the swap for me, she has a couple of Explorers in her family, and sees a lot of 4.6's as she services one of the local police departments and she told me that it's actually a rather common problem for the intakes to warp and start to leak. It was actually leaking a lot more than just the little bit by #8, but most of the rest hadn't become obvious yet.

Thanks again for the helpful input.

 

[BrooklynBay]

Thanks for the update! Your thread is now marked as solved.

 

[davidmmm69]

Thanks for the update...