I just got this 1995 SE with 200,000 on it. Seems to run fine still, but last year the UIM or The LIM started leaking. I inspected the UIM and see it has a Man. date of 1998 so it been replaced once already.
The last owner replaced the oil as soon as he noticed milky oil, and parked the car after he noticed the milky oil again. The car has been parked for a year now, I would like to replace the UIM and redo the LIM gaskits. But I just thought you all could chime in and let me know what you think about this engine sitting for a year with milky oil in it and should i go ahead with the repair.
I dont want the Mains going after i get done, the motor sounds tight, all the miles are from the highway.

I really don't want to swap motors but I live in Flint Michigan and 3800'* are plentifully.

Thanks John Fitzgerald:

1 full years in milky oil and coolant i would say youre chance are very slim that those main bearing are still good and did you start that car this years whit that milky stuff .id say 10% chance youre ok

I agree. As the coolant is lighter than oil, those bearings likely have been surrounded by coolant for the entire year. The odds are not in your favor.

Well, I have a slightly different take on it...

Yes, the bearings have been immersed with dexcool sludge for a year. But if it has been parked all the time and the leak really was identified early, your bearings may not be damaged at all. I pulled one apart that was full of sludge, but still had servicable bearings. (No, I didn't put them back in..I had the motor apart already so replacing them was the most logical thing to do.)

The way I see it, you have nothing to loose if it'* your car. Replace the manifold gaskets, fill it up with regular antifreeze, and flush out the oiling system. Then see what happens. You have a motor with 200k miles on it, there'* really no additional harm you can do to it and all you put at risk is the cost of a set of intake gaskets (cheap gamble in my opinion.)

If the car isn't yours (like you are looking at it as a buyer) then pass it by and leave the mess to somebody else.

Does the crank sit in oil, or does the oil pass trough it? "pop quiz" I'm more worried about the lifters filled with this mixture and the sludge. Thanks J Rogers

no the crank never sit in the oil its at the bottom of the pan so if the engine has not been working that much it maybe ok and the lifter has nothing that the goo can attack like the bearings that made of a softer material

I'm confused by Dick and Curt..

The lower end of the motor does not sit in oil or coolant as long as the level isn't quite overfull. However..that mixture would have pumped through the motor for a little before being noticed. If it'* in the pan.it'* in the oil passages and was between the bearings and parts.

My opinion on it would be to drain the oil.. and pull the oil pan to look over the bottom end for rust etc. At the most you are out some time and effort for the oil pan (under 1 hour). Make your decision from there..although we have not seen a good percent of recoveries after that period of time.

As for the lifters..mostly they would have drained down and you'd be hearing the clatter upon start up no matter.

I am sure Dick meant to say that coolant was heavier than oil.

I have repaired more than a few cars with coolant in the oil and have found that over time, the emulsion that forms when the oil and coolant are mixed and circulating, slowly breaks down to re-form distinct layers of coolant and oil. After a car has been sitting for a month or more, the oil on the dipstick can look perfectly normal although a quart of coolant may be lying in the pan underneath it. When the oil drain plug is removed in this case, coolant, being heavier than oil, comes out first, then you see a mixture as the oil joins and finally, the stream changes to oil.

In such a case, you would expect the same to happen at the crank journals. That is, that the coolant would separate from the emulsion and drop to the low point against the bottom of the bearing shell and the low point of the journal.

The question is: Did the coolant damage the bearings? Sometimes it does, sometimes not. I think an important factor is how long the car was operated with an emulsion of oil and coolant. The lubricating properties of an emulsion compared to motor oil are so poor that bearing damage is likely to occur quickly. The type, condition and age of the coolant are important as well. Organic acid based coolants (like Dex) actually become corrosive as they age. And the chemical additives designed to prevent corrosion become depleted over time in all glycol coolants. So, old coolant against bearing metal, (aluminum, tin, lead) is much more likely to cause damage than fresh coolant.

I agree with Curt, that it is worth a try. I would go sparingly on the RTV silicone on the corner joints of the LIM, and use none on the rail pieces so that if the bearings are shot, the new parts can be transferred to the new donor engine.

@ 220,000 you have nothing to loose. As Bill said drain the oil and see if coolant comes out first. The proper way to ensure its safe IMO is like Boosty said. Remove the pan and inspect for rust.

I have pulled the whole intake apart, the valley looked good [no real build up] I also pulled the tappet covers. Here is were i found build up of oil and water gunk. from this i feel there was a lower intake failure.from a water pump leak. water push into the upper head area around the rockers and back into the valley and down to the oil pan. the EGR tube looked all right on the upper intake. should i still get a new one? i scoured one on e-bay ,new + gaskets for $46. shipped. I will still pull the oil pan just to make sure it'* clean. i have some gunk I'm going to clean up on the top side of this motor. I'm still pissed, GM put such shitty Brake and trans lines in this, and other cars. The body wont rust but the Fluid lines and the engine cradle will.

Thanks J Fitzgerald