Hello all, I have a disturbing question to ask but I will give some up front information first. I bought the 2001 Bonne new, and had the coolant leak recall done by the dealer about 2 or so years ago. After they were done I put a bottle of stop leak in just to make sure everything got sealed up. Last week the thermostat went bad, with the engine temp maxing out at about 130-140 degrees. I purchased a new 195 thermostat, completely flushed the system, refilled with new Prestone DEX (I was not aware of this site and all the issues with DEX-Cool) and installed the thermostat and bled the system.

I drove to work the next morning (14 miles each way) and when I got home the overflow tank was down to the cold mark. I thought there may have been some air left, so refilled it back to the hot level. The next day I drove to work and rechecked it and was down a little. Drove home and was down some more and I catch a whiff of coolant. So now I am at about 60 miles since the thermostat/refill change. Now I start Googling the net and seeing all the Intake Manifold/LIM issues. I drove to work a third time and the over flow tank is down more. Drive home, smell coolant, tank nearly empty, and call it quits at about 90 miles since the thermostat was replaced. Now convinced it is the IM, I went down to Autozone and picked one up (funny they had 3 in stock?) for $129, a Dorman make and a set of LIM gaskets (FEL-Pro) and again not aware of the aluminum ones, as I stumbled on this great informative site after the fact.

I R&R the IM and LIM gaskets, button everything back up, run the engine for probably 10-15 minutes checking for leaks, all looks good. Now Sunday morning, I decide I should probably change the oil in case the coolant leaked in to the crankcase. When I removed the drain plug, OH MY GOD! It was like a frozen chocolate milkshake oozing out. My heart sank in to my stomach, I was sick at what I was looking at. I took off the filter and it was totally full of what look like brown gooy molasses. I was in a near panic.

I went and bought 4 5qt jugs of oil, filters and a bottle of Gunk engine cleaner. I filled the engine with good oil and filter, ran the engine for a few minutes, drained the engine and still was milky. Filled back up, new filter and the bottle of Gunk, ran 10 minutes, drained, and looked better but still lightly brown. Refilled again, new filter and ran for about 20 minutes, drained and looked clear. Refilled, new filter and oil on the stick looks clear. The oil has been in for 60 miles (2 trips to work) still looks clear, coolant tank stays at the full level, no coolant smell, no knocks or clattering, so looks like a good fix. I plan on changing the oil after 250 miles.

I never thought to check the oil level as the engine never burned oil, and never thought about the coolant contaminating the oil.

So, finally, here is my disturbing question. With all the experience with this issue, and knowledge on this web site, what type of internal damage, if any, would I expect possibly running the engine for 90 miles, plus that 10-15 minutes after the IM/LIM replacements? It is running as usual right now with no abnormal sounds. Should I do anything other than what I did?. Thanks for any support or informatioin.

By the way, I too have nearly every problem discussed in this forum from window regulators, to steering, to vibrations, etc etc stc. I’m glad I found this site.

Dave

My 95 Lumina ran for about the same number of miles before i realized where the coolant was going. After doing the same thing you did, it ran for another 35,000 miles before I traded it in. Someone else may chime in shortly, but I had no problems... you did the best thing you could for it by keep changing the oil...

By the way... it may also be helpful for future problems to indicate which engine you have in your signature, or atleast tell which model badge. Since the model badge will also let others know whether you have an L36(NA) or L67(supercharged).

Dave,

Sounds like you did the right thing. Obviously, no one can make any guarantee'* on what will happen. time will tell. I just went through the whole UIM LIM gasket deal too. My engine actually hydrolocked after setting. I changed the oil and filter during the repair and ran it 75 miles, then replaced oil and filter again. so far so good. My oil looked clean, unlike yours. I'll keep my fingers crossed for ya!

I agree, you did everything (post leak) you should have done. Regarding your peace of mind, if it were me I would drop the oil pan (an easy thing really) and remove one connecting rod lower end cap and look closely ate each bearing surface, the rod cap and the rod bearing surface itself. This should be a fairly easy thing to do. Of course you will not be seeing the crank bearing surfaces but my bet is if you see a nice unscored connecting rod bearing surface you will be okay. If you are extra anal go ahead and loosed up a second one, bu torque the first one back into place first. When you are satisfied button it back up, by the book, using a nice fresh oil pan gasket and then sleep peacefully. If you see unusual scoring or particularly scorching of the bearing surfaces who knows how long she might go, but she will "go" from bearing failure sooner or later, but maybe not while you own her.

If you go this route how'* about some close-up pics of those bearing surfaces. Oh, and another thing, while you have the pan off you can see just how good a job you did trying to purge the puke out of that engine.

Thanks for the inputs. I think dropping the pan and checking a bearing is the best thing, plus it will give me a chance to look "up" inside the block. Since I'm in Denver and no heated garage I'll try once a descent couple of days are forcast.

Dave