Lower Intake Manifold Surface – Chevy Blazer 2001

[fcobob78]

Hello,

I’m in the process of replacing the lower intake Manifold Gaskets on a Chevy Blazer 2001 V6 4.3, with about 130k miles on it.

I discovered after cleaning well the surfaces that the lower intake manifold has a substantial amount of pitting. I’m thinking this warrants a machine work?. I would like to hear people’s experiences with this. I read about smearing RTV silicone in this area, but the gasket instruction does not recommend this. Looking at the surface, it looks pretty beaten down, so I’m guessing a machine work is in order?

The surface of the block has some pitting but is not as bad as the lower intake, so I’m thinking on leaving this alone or using the RTV smearing method.

Another question is regarding the two rear coolant passages. Why does GM seals these passages? It doesn’t seem like the block had any seals, but rather was filled up with gunk when I cleaned. Just curious on why these are sealed. Is there any type of cement paste kind I can put in here to bring the sealed surface back to matting surface level? That surface looks pretty beaten down as well.

Hope the attached pictures help and I would appreciate any advise on machine vs silicone

Thanks,

Francisco

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Topic

[fcobob78]

Thanks. I’m going to pick at left hand drill bit. I already have a hole but that easy out didn’t do a thing for me and is becoming a nasty job. The hole is not very good as the piece of stud started to break, Im almost tempting to carefully break it down into pieces by drilling carefully. But like I said I think I still might be able to give the left hand drill bit a shot.

After getting it out what do you recommend for restoring the thread?

Thx for the help

[Its me]

[quote=”fcobob78″ post=115290]Thanks. I’m going to pick at left hand drill bit. I already have a hole but that easy out didn’t do a thing for me and is becoming a nasty job. The hole is not very good as the piece of stud started to break, Im almost tempting to carefully break it down into pieces by drilling carefully. But like I said I think I still might be able to give the left hand drill bit a shot.

After getting it out what do you recommend for restoring the thread?

Thx for the help[/quote]

After you remove the broken thread restorer, clean the hole out with a spray degreaser and then blast it with shop air while holding a rag over it to catch all the loose particles… Do this a few times… and ensure the hole is completely clean and dry (you don’t want to hydraulically destroy the hole)….. Then use a new thread restorer, turn a whole turn, turn back again and go slowly and deliberately, turn and turn back….. take your time… Nobody is timing ya!!! 🙂

-Karl

[EricTheCarGuy]

It may prove difficult to remove the thread chaser. It may require a special diamond drill bit in the end. I hope that’s not the case. That said it seems you have your work cut out for you and you know what you need to do. Good luck and keep us posted.

BTW also a little oil on the thread chaser is a good idea for future reference. Also cleaning the holes with a little compressed air before you start is also helpful.

[Author]

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