Thoughts on Engine Flush

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Originally Posted By: GeorgeHill
Originally Posted By: SteveSRT8
Yeah, wrong forum.

Anyways, we use Kreen around here a lot and on many different types of engines with great results. It is a terrific cleaner.

But if I had a severely sludged engine I would take a few cans of carb cleaner and spray the engine parts with the valve covers and oil pan off to get rid of the caked on garbage. It sounds as though the OP may be becoming an expert at oil pan removal!


Steve, thanks for the reply, some might call me an expert on bmw oil pan removals, I have easily R&R over a 100
smile.gif
severe des luging is out of my experience though.


I have done this on american engines, when the oil pan is off the carb cleaner blows right through opening oil drains and such. VERY effective, just make sure you give it time to evaporate completely and watch out for sensitive oddball components that may react to the STRONG solvents...
 
That would he my big concern with using this method, that carb cleaner would eat seals and gskts. I don't think it would cause a problem with the timing chain guides and Vanos solenoids and Vanos actuators but i don't know either. I guess I will pull the valve covers, lower oil pan and Vanos solenoids. Throughly clean with carb and brake clean all but the most stubborn particles. Reassemble and perform a "flush." Then pull the pan back off and take a look. Maybe do a second flush depending on what I still see. Then fresh oil AMD filter and cross my fingers haha.
 
Originally Posted By: askani79705
What color is the sludge ?


Excellent question. If the sludge is black, that (to me) would be normal engine sludge from a neglected engine and should clean up pretty quickly from what you're doing. However, if the sludge is the famous "milkshake" sludge, you've got some pretty serious engine problems, (blow head gasket, cracked block, etc) and oil and coolant are mixing. If this is the case, no amount of cleaning will eliminate the sludge as it will simply continue to create sludge every time you run the motor.

What does you coolant look like?
 
If the sludge is black and thick, that would be "normal" engine sludge from a neglected motor. You will need to pull the valve covers and have plenty of paper towels on hand, (the shop towel kind) and start wiping. I've seen some so bad I literally scooped the gunk out with my hands. After the heads are clean, pay careful attention to the drains in the head. Drop the pan again and make sure oil will flow from the heads to the pan. You might even want to throw in a new oil pump. When everything is back together, fill with HDEO and a new filter. Change in 100 miles. Repeat - change in 500 miles. Repeat - change in 1000 miles.
 
One final warning (from me at least) - DO NOT USE THE "FIVE MINUTE FLUSH" STUFF! It will loosen and break up large globs of sludge and seriously clog your oil passages. I've seen it happen and it ain't pretty.
 
Originally Posted By: GreeCguy
One final warning (from me at least) - DO NOT USE THE "FIVE MINUTE FLUSH" STUFF! It will loosen and break up large globs of sludge and seriously clog your oil passages. I've seen it happen and it ain't pretty.


A counter argument to that is that it is happening already using normal oil. At least with the engine flush, you are doing it in a somewhat controlled way.

for me its either, go all in and hot flush a few times, or strip the engine covers off and clean it that way. I don't see a halfway house here...
 
From what I know based on experience of using Kreen, it sounds like a perfect candidate for using it.

Why do I say this?...because of all the engine cleaners out there, I woulds say that Kreen is THE one where the [censored] will be dissolved, not floating around in chunks. Its wicked POWERFUL stuff, handle with great care/attention.

Cheap, HDEO with a full qt of kreen and run it no less than 500 miles, swap oil/filter and from the sounds of it, repeat.

Good luck.
 
It is sludge from being neglected, not by product from another failed component. The car is not driveable so I think we are past the point of being worried about clogging passages as that is already happening. Except it is clogging the oil pump pickup itself, my experience has been that BMW oil filters do an excellent job of catching big particles so as along as I can keep the oil flowing to the filter I'm not to worried about downstream if the filter is kept from completely clogging.

I'm most concerned with damage to other components like valve stem seals, gskts, etc with using harsh chemicals. I think I will start with pulling the valve covers off and cleaning by hand, then following with an idle flush or two. Unless someone has first hand knowledge this is a bad idea

Thanks again, George
 
My buddies dad has tryed those engine flushes twice now, in his f150, and his dodge intrepid (2.7 sludger) and both times he spun bearings in the bottom end shortly after doing the flush. I would advise against using any kind of flush. I would clean out what you can manually and then run an hdeo or high mileage oil with some kreen.
 
Originally Posted By: askani79705
What color is the sludge ?


Am I being silly but is oil sludge not always black?
 
Originally Posted By: galaxy333
Originally Posted By: askani79705
What color is the sludge ?


Am I being silly but is oil sludge not always black?


Depends on what caused the sludge. Not changing the oil on a regular basis will produce a thick black sludge. Water or coolant making its way from the cooling system into the motor will produce either a light brown sludge or a white milky sludge. All are thick and nasty to deal with.
 
Remove the valve covers and clean what you can manually. A parts washer may help.

Drop the pan and clean it and the pickup too.

Reassemble, fill crankcase with HDEO, maybe Supertech or Rotella 15W-40. Put a new filter on.

Add a pint of Kreen. Run that OCI as long as you can, up to 1k miles.

Remove valve covers and oil pan for additional cleaning/inspection.

Take before/after pics, please!
 
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Every bit that you can get out from under valve covers etc. is a bit that you don't have to deal with in the pick-up, so definitely do that.

Thinking there's got to be a way of cleaning the screen when you notice that it's restricting...e.g. dump oil, fill with kero/diesel to the normal oil level, dump, filter and re-use the diesel/kero for 3 - 4 "tide" changes around the pick-up screen.

Solvent and movement may dissolve/break free the stuff on the screen such that you can avoid the sump off component...without sending solvents through cam actuators etc.
 
Subaru of America actually has their own labeled oil flush as well as a TSB recommending it during the first signs of oil screen clogging (p0011 and p0012) in a turbocharged car.

-Dennis
 
That's a drag to have to drop the pan to clean the pickup screen. Is there any way to move the oil pump backwards to backflush the pickup, then drain?

On my SBC and Pontiac all I have to do is pull the dist then run the priming tool with the drill going clockwise.
 
You may want to do some research on this, I heard that diesel fuel is quite efficient at flushing out engines too.
 
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