Hey I think the UIM on my 94 PA is starting to go. When I start the car in the morning steam pours out from where the UIM meets the block, and a little dribble of coolant goes down the driveway. I've been watching the coolant levels and only had to replace like 1/2 a cup (over 2 months). Anyways I was in the car parts store with my father and he showed me this new Bars Stop Leak Apparently its safe to use. I honestly don't have the money or time to fix this, so I want to give this a shot. Has anybody tried it? Any successes or horror stories? I used the other stuff on my Honda with a blown head gasket years ago with no ill effects.

Here'* the best advice you'll ever get:

DO NOT USE ANY COOLANT STOP LEAK!!!!

There, now that I have that out, let me tell you why.

Coolant stop leak will not stop your UIM leak. You need to get that fixed. Also, its very unlikely your UIM if its a 94. Only 95+ Bonnevilles had the problem with the UIM cracking and leaking due to the EGR stovepipe. This is more likely to be your LIM gaskets. Stop leak is designed to fill crevices and block flow. No matter what anyone tells you, this WILL reduce flow in your radiator and heater core, and will reduce the efficiency and capacity of your cooling system. If you have a coolant leak, fix the coolant leak. Bandaids will only cost you a whole lot more in the future. I don't care what marketing gimmicks are out, what anyone tells you otherwise, or what'* written on the bottle. Stay away from it.

Verify first that its the UIM that'* leaking. There are a few areas on this car that could be leaking. Check under the throttle body at the lower intake manifold, and see if it has dried up coolant on it. The UIM occasionally warps and causes a gap.

Check under the alternator. there should be a small hose that goes from the lower intake manifold into the water pump. The fitting that connects the hose to the manifold is made of pot metal and breaks and leaks. If there'* a leak there, fix it.

Obviously, check your water pump and radiator hoses.

What he said. never put anything like that in your radiator. You risk clogging the radiator, and that will end your leaking problem by killing your engine. There is no such thing as a fix in a can.