GM intake gaskets

[bxd20]

I'm just about done replacing the LIM and UIM gaskets on my 3.1L 1995 Cutlass Supreme Convertible.

During the process, I am sure that coolant and probably solvent cleaner got into the engine.

The coolant leak prior to me opening up the engine was not bad, only showed up in oil analysis not visibly to the eye.

I am looking for recommendations on when and how often to change the oil. Right now it's only got a couple hundred miles on the oil, but I think it's contaminated badly and I was going to only run the engine long enough to get the car up on some ramps to change the oil. Like 2 minutes. After all doesn't oil roughly speaking cycle through the whole engine a couple times a minute?

Then I was going to run that oil for a few days, maybe a couple hundred miles, and change it again, making sure there was at least one good-and-hot highway run in there.

Then I was going to do the 3rd change, and this was the first batch I was going to have analyzed.

What have others done?

Thanks
Brian

 

[IslaVistaMan]

Probably darn close to what you're planning, '20. It will take a number of times to fully flush the coolant out, so don't be surprised if your UOA comes back saying so.

Might want to consider an Auto-RX clean and rinse, and then with the third oil change after that, do your UOA.

I'd do it like this:

2-day run on new oil ==> 1,000 mile run on new oil ==> 1,500 mile ARX "clean" cycle on new oil ==> 2,000 mile ARX "rinse" cycle on new oil ==> 3,000 mile run on new oil and then UOA at drain.

Might be overkill, but taking a UOA at that point should definitely tell you if you still have a problem.

 

[bxd20]

I think I'm on the right track. Tonight might be the night I finally start it back up. Will be a good feeling.

Only thing I'm wondering is: roughly speaking, how long DOES it take for oil to make ONE cycle around the engine???

 

[eljefino]

You might consider letting it sit very still then pulling the drain plug and quickly stuffing it back in. Water should settle below the oil in the pan.

Hopefully you have some really cheap oil, like that Delo 30 that was $.99/gallon last winter, to flush 'er through.

I wouldn't run Auto-rx for a longer while, it is not sludge you are fighting presently. 3-4 changes in a short time is not unreasonable, I think I did 5 in a k-car I got with a blown head gasket, the first 2 or 3 had "peanut butter" visible so I doubled that number of changes before calling it good.

I only used 2.5 quarts per change though for the first couple changes, figure it got more cleaning done for the money.

 

[JHZR2]

change right after the gasket change, then again after 100-250 miles... Id suggest then doing it again after another 500 and again after another 1000. Then move to 3000 and if everything checks out, then go to whatever OCI you like.

Overkill perhaps, but I can tell you that I had a very slight leak in my 4.3, and it took MANY oil changes after the repair for UOA to point to it as normal. It went down and down, but it was always there in elevated quantities. and I only had 0.1% glycol, 0% water, and ~60-70 ppm of Na and K. Certainy not a 'leak'.

Just buy the cheapest name brand oil you can find, and use it. Being the summertime, dnt be afraid to use an HDEO as its probably cheaper in the gallon jugs than the other PCMOs on the shelves at wal mart...

JMH

 

[bxd20]

I had around 100-150ppm NA and K. Oil never looked contaminated. I think the percentage was 0.3%.

Started it this morning for the first time. After making sure the engine was idling correct and not spewing any liquids - drove it up on ramps and pulled the drain plug. Milk shake ! Then a milk shake / oil combination came out side-by-side like "twist" flavor ice cream out of a soft serve machine. Then it went to all oil. Then at the end it was dripping milk shake. I took off the oil filter and more milk shake there. Since I was going to work anyway I left it open to continue draining all day.

I am surprised at just how much coolant spilled into the engine during the intake removal.

Will probably drive a day and then change it.

 

[JHZR2]

wow, given that, change more, and more often..

I still like havoline for the add pack - but to get a good flush, maybe you should think about buying el cheapo oil just to send through.

JMH