Bought a Sludge lemon. Is it fixable? BG flush?

[iverson03tj]

So I bought a BMW 535 and everything seemed good until I opened the valve cover. I was experiencing lower than average oil pressure. I'm getting about 24 to 26 at idle. Just bearly within spec.
Buy most people are getting around 35 psi at idle.

I dropped the oil pan. Replaced the plastic oil pickup tube. There was a few plastic peices from the old timing chain in the oil pick up tube...
I changed the rod bearings while I was there too.
But that didn't really improve the oil pressure. Opened the head due to vanos codes and seen this mess...

My question is should I use something like BG engine cleaner. As I seen it helped increase the oil pressure. Or some other engine flush. I tired shorter OCI around 1000kms.

 

[iverson03tj]

I did clean up the top end as much as I could with diesel. Vacuumed and then blew out anything loose. And flushed out everything before putting the new oil pickup tube and bearings

 

[Lubener]

I would leave it as is. You will do more harm trying to clean up the mess. Doing more frequent oil changes is what I would do. You don't want a chunk of loosened slludge plug an oil passage to a bearing by doing something more aggressive. . The only sure way to clean it is to tear it down.

 

[Bailes1992]

Does Valvoline R&P come in a high HTHS formula in the US? That might be a good shout here for a slow long term clean up.

 

[sw99]

Sound like a good candidate for AutoRx - https://auto-rx.com/

 

[74DartSport]

HPL engine cleaner

 

[GSCJR]

I would leave it as is. You will do more harm trying to clean up the mess. Doing more frequent oil changes is what I would do. You don't want a chunk of loosened slludge plug an oil passage to a bearing by doing something more aggressive. . The only sure way to clean it is to tear it down.

+1

 

[Cujet]

HPL engine cleaner

One good suggestion.

Any of the high end synthetic oils will clean. M1's HM oils are good at this. BMW's are known for sludge because of infrequent oil changes. I looked at a Z4M years ago with about 60K miles on it. The car was absolutely perfect, ran wonderfully. But the sludge was self evident. I passed on the car. The oil change history was 16,000 mile oil change intervals. And the oil used was if I remember correctly, 10W-60. Quite a wide viscosity spread, which means tons of VII's. The end result was not pretty.

Compare that to my use of M1 and 5K OCI's. No deposits, ever. My 230,000 mile Jag is still perfectly clean inside and runs wonderfully.

 

[ecotourist]

The BMW dealer's mechanic suggested that, if I wanted to keep my 528i long term, I should change the oil at half the interval suggested by BMW. I guess that was the reason.

The other part of the suggestion was that I replace the oil but not touch the oil life monitor. That way the maintenance minder stayed in proper phase.

 

[Sandstorm]

You need the BG engine restoration kit for that. The EPR won't do much.
HPL EC and VRP are safer options.

 

[joekingcorvette]

I would do the frequent oil changes with the Mobile 1 high mileage and also use some sort of engine restorer. I am wondering if the engine is noisy because of all the sludge. If the engine is quiet to start with it will probably last a long time with frequent oil and filter changes but the low oil pressure is scary.

 

[meep]

You did good - physical removal is by far the best, and taking care of the pickup was spot-on. I’ve owned worse and saw them improve. What I would do - as said above, run a high quality synthetic at 5-7.5k intervals, with a half-can of seafoam in the sump. I might go up half a grade in viscosity. Then just drive it. Slow cleaning is good cleaning. The seafoam contributes to slow cleaning.

 

[OVERKILL]

What oil are using using currently?

 

[demarpaint]

I'd start by carefully cleaning what I can see. Then try a good engine cleaner for a few short OCIs.

 

[KrisZ]

If you cleaned up the oil pickup tube and the pressure remains low, then it’s your oil pump. A restriction on the pressure side of the pump will cause higher back pressure, not a lower one.

So it’s either the oil pump or the crank bearings.

 

[Donald]

Sound like a good candidate for AutoRx - https://auto-rx.com/

+ 1

 

[Donald]

If you cleaned up the oil pickup tube and the pressure remains low, then it’s your oil pump. A restriction on the pressure side of the pump will cause higher back pressure, not a lower one.

So it’s either the oil pump or the crank bearings.

You can measure the the crank bearings with plastigauge?

How much is a new oil pump?

Assuming you are using the right spec'ed oil and you are not in the middle of the Mohave Desert I would not expect any flush to improve the oil pressure.

I would change the oil filter. It's cheap. I have seen clogged or defective oil filters do weird things with oil pressure.

 

[iverson03tj]

What oil are using using currently?

M1 0-40

 

[OVERKILL]

M1 0-40

OK, while 24-26 isn't "low", 35 is considerably higher, that's why I was curious. While ugly, I doubt the top of the head being covered in varnish and carbonaceous grit is having any impact on the oil pressure. Could be the mains, could also just be the oil pump, could also be normal for this specific engine, since you haven't owned it since new.

 

[iverson03tj]

You can measure the the crank bearings with plastigauge?

How much is a new oil pump?

Assuming you are using the right spec'ed oil and you are not in the middle of the Mohave Desert I would not expect any flush to improve the oil pressure.

I would change the oil filter. It's cheap. I have seen clogged or defective oil filters do weird things with oil pressure.

I didn't measure the crank bearing clearance but I did check for radial play. Really dont want to drop the subframe again xD. I did that entire job on my driveway.. not fun.
As for the oil pump I opened it up and checked for signs of wear, A bit of scoring but no deep scratches. Spun it a few times to make sure it worked..

As for the oil pressure. Alldata says the resting oil pressure at idle and operating temp should be 1.5 bar. Which is around 21 psi. But many people with n55 engines state that they have 40 psi at idle...

I did some research into BG and alot of reviews from users state that their oil pressure increased.
But I think what's working for their product is that they rev the engine to 3k rpm for 45 mins.
Would it be OK to put some seafood and also rev it to 3k rpm. The bottom end of the eengine didn't have that much sludge.
I'm wondering if there is some sort of blockage causing oil starvation to the top end which caused the sludge