On my 2000 F150 with 5.4, I developed a coolant leak. 3 of 4 spark plug wells on the driver side filled up with coolant, shorting out one cop, you know the story. Anyway, I pulled the intake off today and it looks okay. I can't find any cracks in the plastic, so I'm wondering if the leak came from the joint between the aluminum coolant crossover and the plastic intake. There are about 4 bolts holding the crossover to the plastic intake, but I'm afraid to remove them unless they have gaskets that I can purchase. Is there a gasket on each side? Maybe it's just like an o ring???.
If I can't find any cracks in the manifold, I guess I'll have to install with new gaskets. What gaskets are best??? FelPro has a pricey set for 60 bucks, and a cheap set for 25 on rockauto. Or should I bite the bullet and buy a new gasket set from the dealer???

 

There is an O ring type gasket formed to fit between the composite and aluminum crossover. Not sure if they make replacements though and typically that is not the issue and they don't fail. The composite will crack, more often than not on the passenger side. It would be the first for me if you have a crack on the drivers side. I would bet it was your intake manifold gasket that was leaking. Any signs on the gasket of a leak?

I went with felpro during my swap. The $60 kit comes with everything including throttle body egr and iac If I remember right.

 

I can't find any good indicator that the gasket was leaking, other than when I got all the bolts out there was absolutely no stick or adhesion between the manifold and the top half of the gasket.
When I look at the joint between the crossover and the composite I can't see any signs of a long term leak, which it must have been because I have coolant in 3 spark plug wells.
I found some coolant in the bottom of the engine V, at the rear, say a quarter inch deep. That must mean at least one of the rear coolant passages was leaking also, not??? The front half of the engine V was dry.
Yeah, I'm leaning to just replacing the gasket on the manifold and leaving the coolant crossover as is.
thanks for your reply.

 

Tough to say in that situation. I would lean toward the manifold gasket. It is best to find them while it is on and operating. Dry everything off, start it up and look around until you find it. But you already have it off. If you are positive there are no cracks on the under side of the manifold near the crossover or anywhere else for that matter, my guess is the gasket. Since you have coolant in numerous plug wells on that bank and some on the back half of the top of the block.

 

You have the two lower gaskets on each side and then an upper for the tuning valve. You sure it wasnt your thermostat gasket leaking? If there is a coolant leak I would think it would be toward the front and would be obvious looking at the intake gasket.

 

Ive replaced those gaskets and got them from a dealer (motorcraft). I had fel-pro on previously from my head gasket change and they only lasted about 4 years...FYI

 

To update and close out this thread, I installed the FelPro Perma Dry Plus gaskets on my intake. They are 60 bucks a set from rockauto, about double the base FelPro gasket set that is also available. They look real nice. I torqued the intake bolts to the Felpro specs, which I believe is 20 foot pounds from memory. That is about double the torque set out in the Ford factory service manual when replacing with OEM gaskets. Anyway, the truck works real nice now, and I can't find any leaks. So, problem solved for 60 bucks. The removal and replacement of the intake looked daunting at first, but is really a pretty basic simple job. A tip for those tackling this again. Don't remove the fuel rail and fuel injectors unless you find a crack in your composite intake. If your doing only a gasket job, leave the rail and injectors in place. In my case, I couldn't break the fuel lines because my tool was crap, so I took the rail off the injectors, and left it sitting in the engine cavity, and pulled the intake leaving the rail behind. Eventually I found a new better fuel line tool, and got the fuel rail off, installed it on the intake while on the bench.

 

Good deal.

You followed torque procedure patterns as well?

 

Yes, I followed the bolt pattern for torquing shown in the service manual. Also, torqued the bolts in 2 stages as set out in the manual. Interestingly the FelPro gasket install instructions advise using a drop of oil on the bolt threads and the bolt head flange where it contacts the composite intake. That is exactly what my Nissan service manual sets out for re-torquing cylinder head bolts on my 03 nissan sentra, as I had to do that head a few months ago. Makes sense to oil the bolts so they torque down smoothly, altho my first thought when I read the nissan manual was that oil would make the bolts loosen after torquing. Not so I guess.

 

There are "dry" torque specs and "wet" torque specs. As far as I remember, the ford manual calls for dry torque on the intake manifold. I went around mine 4 times... because even after the second pass I still found a few that were not in spec.

Found this


"The selection of wet or dry is a function of how the bolted joint was designed. The Chassis Service Manual (for example) will list the proper conditions that go along with the specified torque. Some fasteners are intended to be installed clean and dry, others lubricated. Using lube on fasteners intended to be torqued dry will lead to overtorquing and likely failure. Not using lube on fasteners intended to be torqued wet leads to undertorque and loose fasteners. Also, pay attention to the underside of the head of the bolt and any washer. Much of the friction variation that caused incorrect torque readings can come from these points."

 

That's real interesting. The Felpro instructions set out a wet torque procedure and a higher ultimate torque spec. The service manual does not mention anything about applying light oil to the fastener, so it is obviously a dry procedure, and that must be why it calls for an ultimate lower final spec.
Thanks for all the info.