Decided to help a friend with a project. The truck is a 1998 F150 with the 4.2V6 170K+ miles.

Background:

The truck had its thermostat replaced at around 170K (backwards I'm guessing) and I was told the truck overheated. It would start and run smooth, but looked to be burning quite a bit of coolant as there was a good amount of white smoke coming out of the exhaust.. So Initially I'm thinking headgasket right? I then learned about all of the intake manifold gasket issues on these motors (This motor did make it to 170K without any prior signs of this). Do you think this could be the sole issue? What should I look for on the IM gaskets to confirm they are faulty. Anything else I need to be aware of? Hopefully I will have the lower IM off tomorrow...

Any good writeups for this?

What year did the IM gasket issue get resolved?

EDIT: I was just told the build date was 6/98

 

The gasket issue was resolved after 1/15/98 ENGINE build date. However, the rest of the 98's still had some issues that were resolved with the 99 redesign.

There were also bad front cover gaskets.

 

Nice. Do you know where the engine build date is located?

 

It's on a sticker on the driver's side valve cover.

 

usually the faulty gaskets showed up around 100k. its possible your friend has the updated IM gaskets, and they have just failed now that the truck is 170+

 

Thanks for the input. I guess my main concern now is how much attention I should pay to the headgasket. I would hate to put the new IM gasket set on and still have a leaky headgasket. Is it worth doing a compression test? I almost just want to do he headgaskets just to be safe...

 

you can do a combustion gas check in the coolant to see if you're superheating the coolant.

I would tear down with the mind set you are doing headgaskets, and if you get in there and see an obvious hole in the intake gaskets then just stop there.

 

Intake manifold is out and so are the gaskets...

Anyone know the part number on the defective gaskets? Unfortunately the engine build sticker was rubbed most of the way off all I could see was /04/98 Gaskets don't look healthy either way....

 

Wow. You saved a disaster right there. The Ford part number is right there- XF2E-9439-BB. BB being passenger side and -AB would be drivers side

 

Right, but is that the part number of the 97 defective gaskets

 

Get the gaskets from Ford. They will be the improved gaskets.

 

I cant believe how dirty it was under the intake manifold...





All Cleaned up. Decided to stop and just do the intake gaskets. Put over 100 miles on it so far with no issues..