Thought I was going to finish up my LIM/UIM gasket replacement tonight. When I pulled the LIM I found a lot of gunk in the front cylinder head coolant passages, but it was soft and I wiped it out. The LIM was a different story....

I see 4 square coolant passages. The two in the rear of the manifold seem to enter into a central channel in the casting and then circulate up through the thermostat housing. The two passages in the rear of the manifold were plugged solid as if filled. I started chipping it out and now I have a hole through the manifold to the outiside of the flange. Looking at it closer it looks like there aren't really passages there at all - not enough meat in the manifold for there to be. Are there only 2 coolant passages in this manifold? Why whould a cylinder head passage come to a dead end against the manifold flange? I can see the outline of a square port but now I think I just punched a hole through the thing.... I'll try to get some pics .... help! How much is a new LIM going to run? Oh I hate this Dex stuff.

-Shawn

One coolant passage on each side is blocked off at the head. If you do a search, you'll see pictures of that. Bill Buttermore had also posted how the coolant flows through the LIM if you're interested.

This is the GM part number and dealer cost:
. Intake Manifold 24508923. $319.12

You can check GM parts direct, Rock Auto, or a junk yard for a good one. Another possibility for a good used one is Ed Morad. You can email him at GTPED at MSN . com

Thank you - that clears it up - I need a new manifold and the hole was never really there.

I guess it is my fault for trying to clean out a passage that never existed. Still - the DexCool really ate up the metal there - didn't take much to go right through it. Stuff must be similar to that green blood that comes out in "Aliens"....

Dex can get pretty corrosive if it has much contact with air, such as when the coolant level gets low. If it makes you feel any better, if your LIM was pitted that badly, it needed to be replaced anyway.

I just finished replacing my UIM/LIM gaskets, as well as the UIM and LIM'* themselves. Used the APN part for UIM and aluminum framed gaskets. Snapped off my CTS but I can get a new one. However... I installed the coolant elbow into the LIM as a dry install and almost cried when I started it up and saw a trickle coming out from the LIM end. What can I do to seal this stupid part up (other than taking it all apart again, because even doing that doesn't guarantee the elbow will seal).

I'm thinking about the following:
1.) Cut the elbow and use a piece of hose and clamps to connect the ends of the plastic elbow together.
2.) Use some black RTV all around the elbow joint.
3.) Replace the elbow with some sort of fitting and use hose as in # 1.

Any other ideas? Just like the window regulators, there is someone at GM that needs to be educated on where plastic is acceptable, and where it is not. <sigh>

All ideas greatly appreciated,
Thank you - Shawn

It'* not that bad.

Try wiggling the elbow a bit and see if it'll seal on it'* own. Being a dry install you may have had a small chunk of O-ring come out. (Search on o-ring and willwren for pictures of what probably happened).

The easy fix is to remove the tensioner assembly.
Pull the alternator back out
Then there are two more bolts holding the tensioner to the engine. Being wary of the bottom elbow/metal connection point and the elbow that is leaking..wiggle until the tensioer is off. Then replace your coolant elbow and use a little vasoline or oil/grease to lube the o ring prior to installation.

Put the tensioner back on and you are back in business.

There is absolutely no need to pull the UIM/LIM off to fix the elbow.

I am getting ready to do my LIM and UIM too. What is the recomended replacement coolant? Thanks

Prestone Long Life or the any color

Thank you - this totally saved me! I cleaned out the accessory bracket and replaced both plastic elbows - the vaseline worked. I was surprised by how the heater hoses were loose despite the clamp bolts being tight. <shrug> It isn't leaking so I won't complain.

If you're talking about the hoses where they come off the tensioner, it can be rather disconcerting when you see how loose they are, but that is how they are designed to work.