Leaking LIM gaskets...

[Stick in Mud]

Well, it looks like my up-til-now trusty Pontiac Grand Prix w/ 3800 engine is going to need a little surgery. I just had the water pump replaced, and now the car is leaking coolant. Brought it back to the mechanic, he put a pressure test on it, and apparently the lower intake manifold gaskets are now leaking:

1) Anyone know a good mechanic in the St Cloud area? The guy I'm working with is fine, but his shop is 50 miles from home (where I was when the water pump went out).

2) I've read/heard that the original plastic GM gaskets are known for leaking...while the mechanic is in there, should I have him replace all of them? While I'm at it, is there anything else I should get done while everything is taken apart? I've been putzing around online, and a few sites have suggested a host of other replacements, cleanings, etc.

3) I have to go get the car and drive it back the 50 miles home. Then, I've gotta get it to a new mechanic. I only drive to work once or twice a week--the other days I walk--and I want to get it in quickly. But, I've got to get it home. If I watch the coolant levels, I should be OK for the 50 miles back home as well as driving it around town, right?

Thanks!

[Jeremy airjer W]

What year?

[Wolffy]

Probably not happening but also keep an eye on the engine oil to make sure your not getting coolant in there. It's not likely but that could cause major damage.

[Stick in Mud]

It's a 2007.

I'm far, far from knowledgeable in these things, but I've checked the oil, and it hasn't been rising. My (probably faulty) understanding is that the oil levels would rise if coolant was getting in there. That would be the difference between an external and an internal leak, right?

The only noticeable "symptoms" I can see are the slowly emptying coolant levels and the puddle on the garage floor.

[Eric Wettschreck]

Drive it home the 50 miles, you should be ok. Just keep an eye on your temp guage as it will tell you if you're low on coolant. I'm guessing it's been leaking for a while and you've been fine so far.

Pretty common failure for these engines.

[Stick in Mud]

That's what I was thinking, Eric. What I think about vehicles is often wrong, so it's nice to be right for a change.

[Stick in Mud]

Ok, update: I brought it to a new mechanic today for another pressure test. Figured $15 for a second opinion wasn't too much, considering the size of the expense I was facing.

The test today found no leaks.

[Eric Wettschreck]

It's a closed system. If the coolant tank level is dropping, and you see puddles on the garage floor, it's leaking.

Did he test it while cool or hot?

[Stick in Mud]

I had just driven it 50 miles from Paynesville to St Cloud, and it sat for a minute or so before he had it in the garage. I think he had it running for, oh, 15 minutes or so.

All this is over my head, but his theory was that when the guy put in the water pump, he didn't do something right (burping, maybe?). The "leak" I saw on the floor of the garage was an overflow out of the tank. I dunno. I've tried reading up on this stuff online, but I'm finding so much conflicting info I don't know what to believe.

For now, I'm watching it now to see if the coolant levels change and/or the garage floor shows more leaks.

[Stick in Mud]

Ok, so I just thought I'd share an update.

I walk to work most of the time...maybe on a busy week (barring travel up north, fishing, to the local yarn shop, etc.) I put on 20 miles. Last week I didn't drive far, but I've been watching for coolant on the garage floor, and I'm not seeing anything. No leaking to be seen. Coolant level is stable in the tank.

Nothing in the oil as far as I can tell, either.

Should I take the ol' beater out for a big drive, or--if it were leaking--would it have puked some up on the garage floor by now? I've been watching the temp gauge, but it's tough to overheat on a mile drive at 25 mph.

[delcecchi]

I would try to get some pressure in the system. Drive far enough to get it good and hot would be one way. Any parts stores where you could borrow/rent a pressure tester? (I looked up buying one on Amazon and they are too expensive for a one shot deal)

Drill a hole in a radiator cap and put a valve stem in it, pump up with hand pump? leave it at 15 psi overnight then look at floor.

Rube Golberg signing off.