Engine Sludge

[bigsky]

My 97PA with 120k has engine sludge (discovered by a mechanic replacing the lower intake gasket). He will clean out the big blobs...any suggestions on an additive to help remove the sludge? I have changed oil every 3-4k since owning (at 75k) with "regular" oil 10-30. I ask for Castrol at quick lubes...I think the local shop here uses Mobil. Thanks.

[HotZ28]

It sounds like the previous owner was not as meticulous as you have been with maintenance! Unfortunately, there is no quick “miracle cure” for the sludge condition. It takes a lot of time and neglect to develop sludge and likewise, a lot of time and TLC to eliminate it. You can purchase oil additives that claim to dissolve sludge, however you must think of where it goes, if it actually does dissolve. If you decide to use additives, you need to adjust your oil/filter change frequency, to compensate for whatever gunk finds its way into the oil pan. Most engines have an oil bypass built in that allows oil to flow if the filter is blocked. If that occurs, you have “sludgy oil” circulating through your engine. If you do use something to dissolve the sludge, how will you know how long it takes and how much has been dissolved? Your guess is as good as mine! Good luck!

[Alibi]

Would running some additives through the oil and then dropping the oil pan to clean it of collected sludge work well? I'm just curious...

I know oil pan gaskets aren't too expensive and while youre in there you might as well clean everything else down there.

[bigsky]

Thanks for the replies. The mechanic I am working with is not a big fan of oil additives for this problem (he recommends a couple of "quick" 1k changes with a "normal" routine to follow). His prognosis on the engine is not good...around 20k then get something else. But... I know another mechanic who is (a fan of additives)...he is even suggesting a little ATF (for a very short period) to help clear out the sludge. Dropping the pan after additives and cleaning sounds like a good idea. And...that ever present question...at what point is it better to "punt" (go for a different car)? Gives a guy a lot of motivation to start tearing the engine apart and learning how the darn thing works (of course with manuals and having a spare car available while learning)!

[imidazol97]

[quote=bigsky]... I know another mechanic who is (a fan of additives)...he is even suggesting a little ATF (for a very short period) to help clear out the sludge. Dropping the pan after additives and cleaning sounds like a good idea. And...that ever present question...at what point is it better to "punt" (go for a different car)? QUOTE]

Isn't the problem with using additives to soften/dissolve sludge that you get clumps of goo that can block things, like the oil intake in the pan?

I think I would try the ATF guy-if he's done it before and clean the oil intake in the pan after running that a short time. I'd change the oil filter frequently and Then I'd just go with frequent oil changes relying on the fresh additives in the new oil to remove a little of the sludge each time but not leaving the oil in long enough for any to redeposit.

My dad used to put kerosene into a car motor and run it for a short time like a minute and then drain the kerosene to remove sludge back in the 50s and 60s. That was when detergent oils were relatively new ideas; the older oils did not have detergents.

[spinne1]

Originally Posted by bigsky

Thanks for the replies. The mechanic I am working with is not a big fan of oil additives for this problem (he recommends a couple of "quick" 1k changes with a "normal" routine to follow). His prognosis on the engine is not good...around 20k then get something else. But... I know another mechanic who is (a fan of additives)...he is even suggesting a little ATF (for a very short period) to help clear out the sludge. Dropping the pan after additives and cleaning sounds like a good idea. And...that ever present question...at what point is it better to "punt" (go for a different car)? Gives a guy a lot of motivation to start tearing the engine apart and learning how the darn thing works (of course with manuals and having a spare car available while learning)!

I just rebuilt the engine in my 92 Lesabre. It was a major, major job. It took me about 8 weeks. There are many steps that are critical to do right. All in all it would be good to have someone with more experience help you on the first one. That said, if you decide to do it, it is not undoable. Getting a Haynes manual and an official GM manual is a huge bonus (you'll need at least the Haynes--which will not be entirely clear!). The biggest part of the job is the cleaning of the parts. That took me at least 3-4 weeks. I cleaned everything throroughly, installed new main bearings, new rod bearings, a new camshaft (a ground lobe was the cause of my rough running engine and the reason I took it apart), a new lifter (the others were in great shape), a new timing chain and gears, and of course all new gaskets. You have to clean everything in solvent with wire brushes (unless you have access to power cleaners such as machine shops use). It is very slow work.

The biggest secret to staying organized is to get a notebook or legal pad and document each step you take as a numbered entry. For every part removed, put it in a ziploc with the corresponding number of the step in which you took it off, and also note the size of the nut or bolt, etc. and also the locations with diagrams (especially where there are different size fasteners in different spots within the same steps). You will also need to create a duplicate set of ziplocs for the parts AFTER they have been cleaned (you can't use the same old dirty ziploc). You need an engine stand to reassemble the engine. Keep in mind that if you reassemble the whole engine on a stand, then running the wires exactly where they were may be impossible (which is okay, it will still work, but you may not be able to put the "3800" plastic piece back on the engine--as in my case--but I don't care as the piece is only cosmetic.)

Lastly, the only good way to remove the sludge is to take the engine apart and clean it.