The hidden bolts on the intake I helped with ...were under about 3 inches of water. Your'* sounds like it was starting and hadn't gotten very bad yet.

glad you went after the lowers - they're typically just as bad (or worse) at failing than the uppers... but they don't get noticed half the time.

Sorry, this is a little late, but one mod/upgrade to prevent future failures is to completely ditch the plastic UIM -the new Series III UIM is aluminum and only requires a TB adapter from ZZP or Intense so the L36 TB can be adapted to the L26 UIM.

Cost of this is around $300 if you go through www.GMpartsdirect.com for the UIM.


Good luck and hopefully the Dorman will outlast your ownership of the car.

BTW, how about some up-to-date pictures of your beauty?

Been busy, so missed this one, but just wanted to note that your frequency of failures seems a bit higher than normally reported here. I had mine fail just once so far, at about 125-130,000. So I consider myself luckier than most. On the other hand, my replacement was done by a dealership at the same time as the LIM gaskets and they took me for $1300. Saw me coming a mile away...

Sure wish I'd been on BC back then...

Ya, but that doesn't do anything to cure the issue of the crappy lower intake gaskets. IMO, the lower intake gasket are at just as much risk as the UIM.

IMO, a sleeved upper is quite bullet proof. I will always be concerned about my lowers. I just plan on changing them everything 50,000 miles.

What about the new GM replacement LIM gaskets? I know they are real new and only a few people here have them on, but it seems that they would last longer.

Yes, they are reinforced. I don't run them. I use FelPros. I'm on my 3rd UIM. I did the first one and lower gaskets at 77,000. The lower gaskets were complete junk. SEVERLY deformed.

I then had to replace my UIM gasket (leaking). At the time I opted for a Bob Dillon sleeved unit. That was at 115,000 or so. At the same time I pulled the lower to inspect my Fel Pro lowers and they looked brand new! I still replaced them anyway for piece of mind.

At 140,000 all gaskets and the Bob Dillon UIM are holding up well.

I will likely get back into the lowers again this summer/fall. She should have 160,000 by then.

Can't be too sure when it comes to the lower intake gaskets.

I used the lowers from GM. They were like solid metal plated with gasket sealers around each port. They seemed very sturdy. I'm trying to convince the owner to sell the car, it'* got 60k on it and i just finished the uppers and lowers a few weeks ago. Complete mess.

did you take pictures of those lowers? they sound like the redesigned lowers that no one has provided pictures of.

One important note on doing the lowers.
Itsa important that you meticulously cover the lifter valley with rags or paper towels when scraping the lowers. Any dirt or debris that gets down in the engine oil system could clog the pump intake screen and cause engine failure.