On my 98 Blazer w/4.3 engine, to replace gaskets due to coolant leak, I've removed the throttle body, complete intake, and separated the plenum from lower intake. I need advice on the following:how should I clean the thick sooty coating on inside of plenum and in the lower intake? Fuel injection was working fine so I don't want to replace it. Lots of miles on truck,300K, but in good shape. Should I attempt to clean insides? If so what with? What about the electrical connections? First time to take one of these off for me. I've got all elect. cables and vacuum lines labeled, and everything I took off top of engine in freezer bags and labeled so hopefully can reassemble after putting new gaskets on. After some of the posts I've read about damaging the injector(s) removing them from intake, I'm hesitant to proceed with any kind of cleaning until I get some advice. Have read where some have used a water based cleaner-will something of this sort create problems with electrical connectors? All help and suggestions will be greatly appreciated!

 

My answer might be wrong because I'm still learning. I'm actually in the middle of replacing my fuel injectors. Do you have the poppet injectors still or the mfi? From what I've read, you can easily take out the poppet injects without hurting them but if you have the upgraded injectors, can't take those out really without replacing them. I'm sure most guys would recommend doing the mfi conversation since you're already in there. As for the soot, from what I have been told, it comes back so unless it's really caked up and you think it needs to be cleaned, it'll get dirty again. For the injector ports, I used carb cleaner sprayed on some q tips. And for the plenum cover and upper intake, just some carb cleaner on a shop towel to wipe out down. I hope that helps!

 

When I did my intake gaskets,I stripped the intake,cleaned it with some degreaser and a pressure washer and then beadblasted it.Looks brand new with coat of aluminum cast paint.The gunk can be removed with oven cleaner or zip strip and water.Inspect the gasket sealing areas on the rear and make sure they will still seal with a new gasket,they corrode really bad right there.

 

Davecubs14, Charles Hines, Thanks to both of you for the advice. I can't really afford to replace the "spider system" I've got (incidentally I don't know exactly which system). The injector system was working well when I decided to fix the leak. I'm thinking to clean the exterior as best I can. Prepare the heads and intall the new gaskets, get it back together and see how it does. Hope I've got the distributer marks so I can put it back without creating any timing problems. I've got a pressure washer, but am hesitant to use unless the spider system was removed. Fortunately I've got another car so can take my time with this. Charles did you remove your injector system prior to pressure washing and beadblasting?

BTW Dave, I'm a transplanted Alabamian, Worked a couple of years ago for NASA at Marshall Space Center there in Huntsville.

 

Yes I removed the upper plenum as well as the spider assembly before cleaning,I wanted to replace all the seals anyways.