Engine (1994 Ford Explorer) with lots of carbon build-up

Because of a water leak at the point of the my lower intake manifold, I have painstakingly taken the engine all the way down to that point on my 1994 Ford Explorer with 235,000 miles on it. When I got down there the carbon build-up was to me very enormous. Is that unusual for the age and mileage of this vehicle? I have been told to buy SeaFoam to clean it out and wondered if that was the best thing to use. I would appreciate any “expert” advice on this matter. Thanks ahead of time.

I’m assuming what you’re seeing is carbon build-up in the intake system? If so, this is due to the EGR and PCV system gasses being introduced into the intake system.

This is usually soft carbon build-up in the intake syatem. And SeaFoam isn’t what to use in this instance. Instead use a brake parts cleaner to break the carbon up. Go to the local grocery store and get the largest disposible roasting pan they sell. Then get 4-5 can of brake parts cleaner. You now have a mini-parts washer with the solvent. Remove any electrical components from the intake system, place them in the pan, and spray them with the brake cleaner. Be sure to do this in a well ventilated area.


It’s the best choice. You could use Ocean Spray and it might not offend anybody.

Did you indicate that you completely removed the intake manifold? If so, just take it to an automotive machine shop and have them cook the carbon out with their pyrolytic oven. Don’t let anyone bead blast or sandblast it! You’ll never get the beads/sand out of the nooks and crannies unless you already can see that the runners and such aren’t too circuitous. All the above advise applies also to the secondary intake manifold (plenum).

What engine is this? Metal or plastic intake?