Hey. I'm about to start the intake gskt replacement job this morning (4.3) any tips or war stories would be appreciated. For instance; does oneHAVE to separate the upper and lower manifold? What size is the crank bolt? I'm stunned at the amount of work required just to get to the intake! Thanks in advance!

 

Might try a search on it... There is a very thorough how-to from D-Tips.com that has been linked to in quite a few threads.

No, you do not have to separate the upper plenum from the lower manifold on the 96+ engines. And you do not need to use the crank bolt...

 

Is your truck older than '95? If so, how do you expect to access the lower intake manifold bolts with out removing the upper plenum? I know I had to remove the upper intake when I did those gaskets on my '93 olds bravada (vin w, 4.3 cpi). But maybe you have '95 or later model in which I have no idea if the the upper plenum must be removed. Please specify a year.

 

Welcome to the forum.
Keep it CLEAN, no debris down inside engine.
Flush with a quart or two of oil.
After you start it, run it to operating temp, then change the oil again.
This is what I did, You don't have to follow my method, but I wanted to make sure the oil was free of antifreeze.
Good Luck.

 

One thing to consider... if your 4.3 is older the lower intake bolts are SAE 3/8 x 16, not metric. They look almost the same so make sure to check what you have. You should chase the threads in the head with a tap to remove old tread sealer and you really don't want to use the wrong size.