LQ1 LIM Coolant Leak---again?!

[Galaxie500XL]

I've been losing a small amount of coolant the past few days. Before I left for work this morning, got out the flashlight, and began looking for leaks. Sure enough, I found coolant on top of the distributor stub.

 

It's been less than 3,000 miles since I replaced the LIM because of this very thing...the surfaces were so clean, you could have eaten off of them, and I used Fel-Pro gaskets, and very carefully confirmed that the torque applied to the fasteners was done correctly...

 

What could have gone wrong?

[spiderw31]

I had the exact same issue, and when I took it all apart my gut feeling was that the torque was wrong on the LIM bolts. They just felt too tight as I loosened them, and the gaskets had compressed a bit too much.

 

I think that the setup is just extremely sensitive to imperfections and proper torquing; looks like if the gasket is just a small amount thinner than normal you get issues. Mine's been OK for the last couple thousand miles, and we'll see how long it lasts.

[Night Fury]

Well its a good thing they aren't too hard to replace!

[jtwmechanic]

did you use the steel gaskets? fel-pro offers two different gasket sets. one is steel one is not. steel is the only way to fix it right

[spiderw31]

did you use the steel gaskets? fel-pro offers two different gasket sets. one is steel one is not. steel is the only way to fix it right

 

I'm pretty sure there isn't a metal gasket for the LQ1. Not that I saw listed anyways, and looking at the design I'd say it'd be tough to fill that space with a metal gasket.

[Galaxie500XL]

I've not seen the steel gaskets anywhere, but this sounds like a good idea. Any idea of P/N, or a place that might stock them? Rockauto only seems to have the black plastic ones, and the same for the local parts stores I've been to.

[Crazy K]

I've not seen the steel gaskets anywhere, but this sounds like a good idea. Any idea of P/N, or a place that might stock them? Rockauto only seems to have the black plastic ones, and the same for the local parts stores I've been to.

 

I'd contact Fel-pro directly and ask if they even exist. I have had to use the plastic ones, myself.

[White93z34]

There is no need for steel intake gaskets on the LQ1. I have done, honestly probably 15 plus intake gasket jobs on these things and have yet to have one leak like that, that many of those were before I knew what I was doing and did not use a torque wrench.

 

did you clean the mating surfaces with a die grinder/scotchbrite pad and accidentally take off too much material off the head?

[jtwmechanic]

this listing repairs all 3xxx gm engines, part #MS98003T. not sure about the part # for the LQ1

Edited June 25, 2010 by jtwmechanic

[Galaxie500XL]

I cleaned them with a toothbrush, and a brass brush to get the stubborn deposits off. The original machining marks on the surface still show evenly.

[White93z34]

are you sure its not that dumb rubber O ring that feeds the TB heater? I've had issue with that thing leaking in the past.

[GOT2B GM]

a touch of RTV there can't hurt

[Galaxie500XL]

I've been thinking about that myself the past couple of days...I was tempted to get some UV dye and put in the coolant, and see if I can find a leak...

 

Then again, maybe that yellow Prestone glows already?

[AL]

No, it doesnt, add the dye and keep an eye on it

[Galaxie500XL]

I'll get the dye.

 

A friend asked me if I'm using Dex-Cool...I'm not. Is this a possible issue? I've always used Prestone, the yellow stuff, was this engine supposed to use Dex-Cool, and would that make a difference?

[Night Fury]

Coolant is a non issue!

[WhatTheFehl]

I know the 3100 in '95 didn't use dexcool, I would assume the LQ1 didn't either, but I'm not sure.

[jtwmechanic]

I'll get the dye.

 

A friend asked me if I'm using Dex-Cool...I'm not. Is this a possible issue? I've always used Prestone, the yellow stuff, was this engine supposed to use Dex-Cool, and would that make a difference?

the new types of anti-freeze were designed to keep them from rotting out the aluminum cored rads and heater cores when they stopped using copper and brass. i guess over time the old type could cause rotting around the coolant passages of the heads and water pumps since they are all aluminum. as long as it wasn't the old green stuff i would say you were fine and that it was a non issue like Nightfury said.

[Night Fury]

I know the 3100 in '95 didn't use dexcool, I would assume the LQ1 didn't either, but I'm not sure.

 

My 95 3100 Ciera had dex TYVM

[WhatTheFehl]

From the factory? My GP doesn't have dex, I remember someone telling me it wasn't supposed to have it. Plus I don't have one of those little dexcool warning labels.

[Night Fury]

Yes from the factory.

[jayman]

from experience dex cool is not the way to go. well just personal preference anyway. I was having a constant leak in the same area about a year ago. it turned out to be the little 2 inch hose under the intake near the fuel lines. i had to replace the fuel pressure regulator

[Night Fury]

Experience? Like what?

[birdman]

ive heard that dex is less forgiving if you have air in your cooling system, it tends to corrode things if you dont bleed the system properly.

[Galaxie500XL]

It's looking like that's where mine is leaking as well...it's made quite a mess. There's a small film of coolant almost over the entire subframe! I'm pulling the plenum off to take a look, almost impossible to see anything with the plenum on the engine!