LIM questions

[Nozhayrz]

Greetings All,
I quite by accident found the GAOC and have been reading with much interest, in particular the anxiety the LIM gasket has been causing.

I have a 2000 GA GT RA 3400 bone stock with 67,000 mi. and am experiencing the leak as evidenced by coolant loss and orange fluid collecting on the tranny housing. Also the black residue below both sides of the forward cylinder head. I'd estimate the coolant loss to be about just less than 1 quart per week. No oil in the coolant and no bananna smoothies in the oil pan as of yet.

I've read many of the threads on this site and others about the problem. I'm an old school motorhead type, My Dad owned an automotive machine shop back in the 60's and I have had numerous hot rod projects in particular Big Block swap '57 Chev's and a 69 GTO.

From what I have seen and heard from others about the LIM leak, it appears to me that the problem is not so much that the gasket fails (I don't think the Dex-Cool is eating the gaskets) but that the manifold is coming loose and the coolant, being hot and under pressure, finds it's way out. Once the internal fluids start seeping past the gasket, THEN the gasket itself is doomed and takes the blame for the failure.

Because a few here have performed the repair, can someone comment on the condition of the gasket when it was removed? And how tight were the LIM bolts from the factory assembly? Were they really "finger tight" as I have read?
1) How many bolts are anchoring the LIM?
2) Can they be accessed without complete disassembly?
3) Has anyone just tried re-torquing the LIM to see if the leak stops?
4) If so how much disassembly was required to access the bolts?
I know that's a long winded tirade for a noob, but I can't help my first instinct to just tighten the frikken thing back down!
THANKS!!!

Bill

[rixGAphx]

You can't get to the LIM bolts without removing the UIM.
This is *about* 3 hours R&R, including disconnection from the throttle bore and removal of *most* stuff on top of the engine.

Replacing the gasket just takes one more hour for the LIM R&R.

There's a new gasket design (been available about 18 mos), and replacement of the LIM bolts is recommended.

This seems to be a more serious, and long-term, solution than 'just tightening the bolts'.

One thing about retorquing: You can seal the original leak, only to find that it has 'moved' to a different location. Like into the oil pan :eek:
* * * *
I agree that the LIM gasket and DexCool are probably coincidental problems rather than related or causal.

Welcome to our world.
-Rick

[99GrandAMSE]

http://www.gaownersclub.com/forum/showthread.php?threadid=44742&highlight=LIM

... I just did this a month ago :)

[mikem220153]

Well, to answer your questions
1. There are 8 bolts in LIM. 4 shorter outer bolts and 4 longer inner bolts.
2. You can't get to the inner bolts with removing the UIM, Fuel Rail and Injectors, Coil Pack, Power steering pump, valve lifter rods, and upper engine mount.
3. Retourquing the bolts... Very Bad Idea!! Besides, If you go to all the trouble to remove everything else, you may as well go ahead and do the job right and replace the gasket.

GM came out with a TSB describing the new and improved gasket as well as new torque specifications for the UIM bolts, and as Rick said, they suggest replacing the old bolts with newly designed bolts as well.

If you elect to do this job yourself, go to the GM dealer for your parts. If you go to one of the popular auto parts store, there is not guarantee that you they may not be giving you "New Old Stock" which means the new gasket set may not incorporate the new modifications for the gasket.

If the gasket is leaking externally now, you are riding on borrowed time. It is a pretty good bet that it will start leaking internally before long.

[99GrandAMSE]

Originally posted by mikem220153
... GM came out with a TSB describing the new and improved gasket as well as new torque specifications for the UIM bolts, and as Rick said, they suggest replacing the old bolts with newly designed bolts as well.

If you elect to do this job yourself, go to the GM dealer for your parts. If you go to one of the popular auto parts store, there is not guarantee that you they may not be giving you "New Old Stock" which means the new gasket set may not incorporate the new modifications for the gasket ...

... after reading the TSB, the torque values is still the same as it used to be but it is the method in wich they are tighten. Also, for interest sake, as far as I could tell the only difference between the new and old bolts is the new bolts come with some Loctite applied; although since you are that far, you might as well do as GM suggests and replace them. Contrary to this thought, I didn't use GM gaskets and went with FelPro being we have always had good luck with them on other engines ... just my two cents :)

[Nozhayrz]

Thanks for the info. I have a trusted friend w/ shop who will do the work. He suggested replacing the gasket as well (felpro) and using loctite on the threads.

99Grand: I had read your LIM thread before and must say those are excellent photos.

Thanks to all!