It drank a little bit of coolant over the past 3 months, maybe a quarter gallon. Is it worth it to have these proactively replaced on my beater Bonneville? Was my year more prone or less prone to the failure than other years? How much would it cost at shop rate ~80-100 bucks an hour? If it'* much over $500 then that'* getting dangerously close to what I paid for the car itself.....

cliff notes:

-1992 Bonneville 3.8 N/A
-How does this year differ in regard to the intake manifold gaskets
-How much would it cost to pay a shop to fix it

Moved to correct area.

LIM gasket failure is a some what common thing. If you do the work yourself, you can do it for under $100 in parts.

If it'* not fixed you can damage the engine.

so is it both the upper and lower intake gaskets that fail, or just lower? One site I went on said the Series I doesn't have the plastic gasket and is thus not as prone to the failure.

Me working on a car is going to be like an elderly lady using a computer. Any how-to'* online for this? And how long is it supposed to take a professional to do it?

I got my LIM- UIM gaskets, Valve cover gaskets, Water pump gasket, spark plugs, and wires all for 700 including labor at Pep boys. I didn't have time or tools to work on it myself.

Here'* a write up.

https://www.gmforum.com/t278911/#post1359038

Where are you located? There may be a club member near by that can help. Every shop is different. But 4 or 5 hours is all it should take.

Hey hammer I am having the same problem as you I think. My 92 SSEI is drinking a bit of fluid and having to top off overfill tank every few weeks or so. Since I do not see any visible leaks is there any way to confirm if the LIM/UIM is the culprit?

Most sites point to the later models - mid 90'* for this issue so I don't want to go through the trouble replacing it if it is not the problem.

On a side note is Dex cool (orange stuff) bad to use? It seems to be what is in and I heard that I should get rid of it for regular fill. Any thoughts here?

Thanks guys, Hammer let me know how it goes for you if you decide to have the job done.

Thanks

If you check your oil, look for foam in the oil. Also foam on the inside of the oil cap. That would be coolant in the oil. Look for pooling around the LIM. When you start the engine for the first time of the day, check the exhaust, does it smell a little sweet? All signs your LIM/UIM is leaking.

Is DEX bad stuff? That will depend on who you ask. I say no, it'* not. As long as it'* maintained, just like any other fluid. If it gets low and air gets in to the fluid and or it gets old it can brake down the gaskets. If your going to do a gasket change, just flush the system and fill with green stuff.

If you have over 80k on the car, changing the gaskets is a good idea. There is a write up in the tech info section about doing it. It'* not a overly hard job. But it will take 4 to 7 hours. And you will need a torque wrench. Having help makes it easier.

If you have coolant disappearing in to the void, it'* a good bet it'* because of the gasket.