Plenum removal
 

I need to gain access to the EGR on my 90 L98. This will mean removing the plenum. Can the plenum be removed by just unbolting it from the runners and the throttle body and lifting it out? Anything connected to the underside of the plenum that could cause problems? Any tips would be appreciated.

tom...

Re: Plenum removal (Tom73)
 

There is a tube that goes to the brake booster from the rear of the plenum. The IAT sensor may be under the plenum too and you have to disconnect that before you pull the plenum off. Also mark the vacuum lines. :thumbs:

Re: Plenum removal (War Machine)
 

There's no need to disconnect it from the throttle body. Just disconnect the necessary crap from the TB (not much coolant will spill, but now's a good time to do a coolant bypass so that all future plenum pulls will be easier), and keep it attached to the plenum.

When you've done it as many times as I have, you'll appreciate the throttle body coolant bypass.

Re: Plenum removal (Jim85IROC)
 

What about gaskets? Can you get just those runner gaskets or do you have to buy an entire upper end gasket set?

tom...

Re: Plenum removal (Tom73)
 

I don't know about the gaskets. The 2 times I needed gaskets I was doing a project that required replacing top and bottom. That would SUCK if you couldn't get them separate, if not then that means there's a ton of lower gaskets layin' around from all the EGR folks. :lol:

Re: Plenum removal (Tom73)
 

Tom, I replaced the EGR on my L98 a few years ago. I think any gaskets were OK, but it's been too long to recall all the details. I turned out to be a surprisingly straight-forward job. The toughest part was getting to all the bolts that hold the plenum on... I think they are Torx-30's and some were tough to reach... I used a driver bit and some extensions. I think I did what you were thinking... just unbolted the TB from the Plenum and lifted it out to get to the EGR.

Best of luck... hope it goes smoothly.

Re: Plenum removal (K87ZZ4)
 

Remove the soft vacuum lines on the back/right, remove the IAT sensor connector. You can leave the brake booster line on it and just twist the plenum upwards on it. Use a rubber mallet to seperate it from the runners and hopefully the gaskets will stay in 1 piece.

Re: Plenum removal (scorp508)
 

Dug into mine a few years back to replace the FPR. I had to take the runners off one side to get the plenum off as it was stuck pretty good (12 years and 130K will do that) and I didn't want to break anything. If you can't get the plenum loose the driver's side runners come off fairly easy. I put new gaskets on to avoid pulling it apart twice. :seeya