A while ago I found a couple vacuum leaks under my UIM, and decided to take it apart and replace the gaskets and look at the hoses. I replaced the gaskets but created an even bigger leak in the same area. Took it apart again, got it back together, and now it runs a little better but still a leak under there.

I found a thread a while ago (although I can't find it now) where someone mentioned that the UIM is tricky to get seated and if it isn't on properly will create a leak. I noticed on the driver side of the UIM where the 2 bolts that go into it horizontally, there was a gap between the uim and the bracket it sits on. Is there supposed to be a gap, or is it supposed to sit down flat? I'm thinking it's possible the uim isn't sitting flush on the lim. Is there a certain sequence that bolts go in?

I haven't messed with the hoses yet, but tomorrow I'm going to take it apart again and redo the hoses as well, just to make sure that's not the problem. My gaskets are also taking a beating so I bought some gasket material and decided to make my own just in case they went bad as well.


But yeah if anyone has any ideas with the uim, and other things I should look for, the help will be greatly appreciated.

 

Forget the bolts that sit on the driver side bracket until you have tightened down the 5 LIM/UIM bolts on the passenger side. You want to make sure the gasket crushed in there before you go tightening up the bolts for the bracket. Also, make sure you don't have any hoses in the way or emission rack lines bent that could be keeping the manifold from seating.

 

Alright, I'll give it another try today and see what happens. Thanks man.

 

Well i got everything back together today, and there still a leak. I can't figure it out. Maybe the lim gasket is bad? I've replaced the hoses under the uim and although it seems a little better, the problem is still there. Any ideas?