Clean intake manifold surface
 

I am replacing intake manifold gasket on '99 4.3 Blazer. The gasket around water jacket are trashed and obvious cause of coolant leak. I have the manifold removed and trying to clean up surfaces before installing new gasket. The problem is that the manifold will not clean up (to nice shiny surface).

I scrapped all old gasket with razor blade, careful not to scratch surface. I 'scrubbed' with a small wire brush with engine cleaner and carb cleaner. Looks like a bit of the corrosion will not clean up. So, how do I clean this up?

Don't yell, but I tried to use some fine emery cloth and that did not help. I did not want to do any further damage by using coarse grit. Since I am going to gob some RTV around this water jacket anyway, can I get away with assembling without further cleaning effort or will this eventually leak because of a weak bond.

It seems like the intake manifold has the problem and the head does not look as pitted.

I uploaded some pictures which includes 3 shots of the intake manifold and 1 shot of the matting surface of the head. When I run my finger over the discolored part, it does not seem pitted (i.e., it is not heavily corroded)

By the way, I seem to read some conflicting procedures on the use of RTV to seal the manifold. One procedure says to assemble immediately (within 5 mins), another one said to let it 'skin over' before assembly. So, whats the best way to apply RTV?

Thanks


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RE: Clean intake manifold surface
 

That should be fine, as long as all the ports look like pic #3 when done. DO NOT USE SILICONE AROUND THE WATER JACKETS!!! Just put a dab in the corner where the head meets the block, then put your gasket on, and lay your end seals of silicone. I have seen way too many comebacks because people use silicone around the coolant ports, on the older gaskets this was anOK practice, but on the new styles, it is a big NO-NO. I personaly do not let the silicone skin over before use and have not had an issue doing so. Just make sure yuo follow the torque procedure, and don't over-torque. Good luck.

RE: Clean intake manifold surface
 

I use an Angle Die Grinder with 2" or 3"Rolocsanding disk. Cleans it up really nice and can be run on a normal 5 gal to 33 gal air compressor. Don't need the big 60 gal that most shops have to run it.

http://partimages2.genpt.com/partimages/218888.jpg

Angle Die Grinder new most places have for under $60. The Roloc disk are from 3m (3M™ Roloc™ Discs 361F ), can find them just about anywhere. I have found some of the best prices for the Roloc disk on Ebay, that is if you don't know anyone who works for 3M or a body shop that can get them cheaper for you.

RE: Clean intake manifold surface
 

Just used a razor and elbow grease when I did mine. As Korey said, make sure you torque the bolts down to proper specs. and follow the tightening sequence. Some manuals have the ratings in inch/pounds, just make note of that. I gave the silicone about 2 mins before mating the surfaces.

After assembly, I gave the silicone 2 full days to cure before putting coolant in the system just to be safe. I know people that waited just a day and they were fine. So make sure you let it cure before doing anything.