Thoughts on Engine Flush

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GeorgeHill

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Feb 18, 2014
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Austin, Tx
I just acquired a BMW 740iL with the 4.4L V-8. The car was not running and had been sitting for what I would guess is at least a year. The previous owner had left a few cans of random oil treatments and sea foam in the car and another individual had added a qt of Dexron III to the oil. Now that I have the engine running I am loosing oil pressure after a short distance of drive time. I had both valve covers off and there was a fair bit of oil "sludge" in the cylinder heads. I have also removed the oil pan at least 5-6 times to clean out the oil pump pickup. What I assume is going on is the additives and or atf are causing the debris and gunk to loosen and migrate to the oil pan where they are picked up by the oil pump and then clog the pickup.

So to remedy this I have been removing the pan, cleaning the pickup and straining the oil through a very fine mesh filter and replacing the oil filter when it looks significantly soiled. But this is time consuming and a slow process, I feel the more I do this the closer I am to causing significant engine damage, i.e. wiping the bearings. With that said though it IS working, as I have been able to run the engine progressively longer before the pickup clogs, but every time I drop the pan at this point I have just a slight amount of sludge (only enough to cause the pickup to clog).

I am looking into other options now. I have never been much of a fan in regards to "Oil Flush" treatments, but I think in this case it may not be a bad idea as I can easily remove the oil pan. What is the collective idea on this for my situation?

Thanks in advance, George
 
Welcome GH
Many will recommend an HDEO. This is not my area of specialty. Others will have better ideas than me. However, just thought I would throw out that many BMW's use TTY bolts for the pickup tube.
 
I think if you use anything but oil it will cause more problems use a good oil and run it for 2000 change it out just my opinion.That engine doesn't sound healthy to me sounds like bearings too.JS
 
I recommend change your oil if all that "junk" is still in your sump. But from you describe if you want to save from a engine rebuild or a new engine I recommend a engine tear down and clean all of that goop out of there.

If your pickup screen is that clogged consistently it is only a matter of time before a passage way gets clogged and you will be stranded at a very non convenient time.
 
Hi George. I see this is your first post --- Welcome to BITOG!

I will let you know now that you will probably get some conflicting responses when it comes to engine flushes. Some hate it, some like it, others are in the middle. So, be forewarned.

With that being said...

I would recommend this: First, dump whatever you've got now. Go and buy an HDEO (heavy duty engine oil) from wherever is easiest. IMO, brand won't matter in this case. Be it Rotella, Delo, Delvac, or whatever - any should do fine. The reason being, HDEO oils have a heavier additive package and will help in the cleaning process. As for the grade, your bimmer's manual should say that there are multiple acceptable grades (dependent on temp). Pretty much any of the normal grades (5w-40, 10w-30, 10w-40, or 15w-40 are some of the usual grades) would work, but since you are doing a cleaning, I'd try to get a full synthetic 5w-40. As for the oil filter, just use a cheap one like the purolator classic. Run this for about 3 gas tanks worth of miles. Then add a pint of MMO (Marvel Mystery Oil). Run for another couple of gas tanks, and then drain it.

At that point, drop the pan again and check to see how it looks. If it's still pretty bad, throw in some 5w-30 PYB (Pennzoil conventional) and a quart of MMO for 1000 miles.

If, by then, it's still not clean, you're probably gonna need to take her apart (or have someone do it for you.) That is, unless you're okay with keeping on running short OCI's to clean it. In which case, as many BITOGers actually do agree on, switching brands each time can help because it's using different add packs each time. Just make sure whatever oil you get is API certified.

~ Triton
 
Make sure your timing chain guides are healthy as well or that m60/m62 wont live long. I wouldn't recommend an engine flush if there is sludge visible in quantity on the heads, just short change intervals for now.
 
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Sell the car to another sucker.
An ill-maintained seven series is an expensive accident waiting to happen, and this car obviously has some problems.
The cans of "please help" left in the car were a clue to the engine's problems.
If the oil was left long enough to sludge the engine, then what other maintenance neglect does the rest of the car suffer from?
Sorry!
 
Have you gotten the oil that was in it when you bought it out? If not that should be your first course of action.

You need to dissolve sludge slowly so it can be picked up by the oil filter, not globs that are caught by the oil pump strainer.

I would run Super Tech oil in it for 500 miles, dump that and then use a quality synthetic to clean the sludge.
 
Originally Posted By: Donald

I would run Super Tech oil in it for 500 miles, dump that and then use a quality synthetic to clean the sludge.


While Super Tech conventional is a decent oil, and some argue on-par with the name brands (which I do not argue against)...
How is that going to help clean? ST dino is more suitable for a car without problems. However, if you were referring to ST's HDEO, then I digress and apologize, because that would be fine.
 
The argument behind "clean oil" is that it has fresh additives that will clean.
It being a dirty engine, those additives will be used up very quickly, and therefore a quick OCI is necessary.

About any approved oil will do.

Short intervals are relatively safe.
 
I would say do 1000 miles OCI (Oil Change Interval) three times with Mobil 1 0w40 with Fram Tough Guard filters from Wal-mart. Then report back here with photos.

Since the car has been neglected change all the fluids.
 
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!
 
Thanks for the quick replies! If this is the wrong forum will a mod move it please? When I searched for engine flushes I found threads in this forum as well as the additive section.

To be more clear, the car is basically not driveable. If I could go 500 miles I wouldn't be posting, but instead I can drive a mile or two before it clogs. And when it does it is just a small amount of sludge, only really enough to cause the pickup to clog. If the best course is to continue what I am doing then I will as it's only time and it is working. The reason I posted though is I have zero experiences with engine flushes and normally wouldn't consider but this is an extreme case and I'm considering all options. If I have to go through the engine than I will but that is only if I absolutely have to, as in it wipes a bearing.

Thanks for the comments, George
 
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 think a proper engine flush treatment is far better than having chunks of snot floating round the engine, waiting for the oil to do it for you.
 
Another vote for removing the valve covers and oil pan and a good manual cleaning. Then a short run with Kreen, and another pan drop. It is the junk that is not accessible via under the valve covers and up inside the engine that you can't reach that is the problem. But the more garbage you get out manually the better. I would even consider a very short run with an idle flush after the manual cleanup, then pull the v/c and pan again. BTW I'm not a fan of idle flushes, however in this situation it might not be a bad idea.
 
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