Bore Scoped Cylinders

[Fifty150hs]

Originally Posted by Effduration

Consider this engine flush... Which has gained quite a few fans over on E46fantatics.
Attacks the oil control piston rings from both top and bottom.

Please see the flush in the link below. The author, MrMCar, was(is) a factory-trained, long-time independent BMW tech in New Jersey. He recently retired. He did this routinely for his M54 customers with oil consumption issues.

https://www.e46fanatics.com/threads/...n-fix.1335303/

I have read this before and it looks like it works, but I don't have crazy high oil consumption, at least I don't think so. I only use about 1 liter per 5000 miles. I'm hoping it would help with lowered compression. I'm going to try the oil in the cylinder trick to see if it brings the compression up. If it does, then this process will be next.

[miloh]

Awesome pics, awesome situation for those pics too.

[Fifty150hs]

Originally Posted by Effduration

Consider this engine flush... Which has gained quite a few fans over on E46fantatics.
Attacks the oil control piston rings from both top and bottom.

Please see the flush in the link below. The author, MrMCar, was(is) a factory-trained, long-time independent BMW tech in New Jersey. He recently retired. He did this routinely for his M54 customers with oil consumption issues.

https://www.e46fanatics.com/threads/...n-fix.1335303/

My only concern with following this method is that you run the engine for four hours (half a day?). The instructions call for it to be run 10 to 30 minutes. Running it longer makes me nervous that running oil that has been thinned out by the BPR for too long, creating a bigger problem than I already have.

[Effduration]

Originally Posted by Fifty150hs

My only concern with following this method is that you run the engine for four hours (half a day?). The instructions call for it to be run 10 to 30 minutes. Running it longer makes me nervous that running oil that has been thinned out by the BPR for too long, creating a bigger problem than I already have.

Yes, I admit that gave me pause also, but for different reasons. I have seen and heard too many stores of unattended M54 cars left running only to overheat.

"Running" in this case means let the engine IDLE (<1000 rps) with occasional blips. Also, yes a can of BG EPR will thin out the oil, but is 7 quarts of oil and one can of BG EPR

The manufacturer is never going to recommend a 4hr idle session due to general liability and the risk that the owner doesn't do the flush correctly. There might also be a risk of the oil filter getting clogged with sludge.

But please spend some time reading MrMCar's posts on the E46fanatics fourm. He was an experienced tech/shop owner and explained how he developed and used succesfully, this method...If you wanted to, you could even track down one or more of the techs who worked with him and/or Gary Smith the BIMRS tech trainer he discussed it with. Heck with a little searching, you could likely get MrMCar himself on the phone..

[Fifty150hs]

Well I did the BPR treatment today. Four hours idling with a can in the crankcase. Blipped it every thirty minutes. After four hours I drained the oil and pulled the filer. Then pulled the plugs and put BPR in each cylinder. It still in there. In the morning I'll drain out any BPR that may have gone past the rings. Hopefully pulling more carbon out of the rings. The oil I drained was very black. Once I clear any fluid left on top of the pistons I'll stick the plugs back in and put fresh oil in. I lifted up the right side to level out the piston tops as much as possible. See photos.

[Effduration]

That's the way to do it man !
Did you have temps displayed on the cluster the whole time? Did you add any cooling, like a box fan placed on engine while it was idling? I am guessing the neighbors didn't show up and say "did you know your car has been idling for hours"?

I'd expect a huge smoke show when you start it.

Please keep up posted. Extra black oil on the drain is obviously a good sign.

[Fifty150hs]

Originally Posted by Effduration

That's the way to do it man !
Did you have temps displayed on the cluster the whole time? Did you add any cooling, like a box fan placed on engine while it was idling? I am guessing the neighbors didn't show up and say "did you know your car has been idling for hours"?

I'd expect a huge smoke show when you start it.

Please keep up posted. Extra black oil on the drain is obviously a good sign.

I have an AVin head unit with the OBC display so I was monitoring temps the whole time. I started out with the hood up and the heat on turned to 90. After an hour it was only 180 degrees, so I turned the heat off. temp then rose to 201. Turned the heat back on low and it took the temp back down to about 180. It was a cool day with wind so it wasn't fighting high heat.

Neighbors are used to seeing my car with the hood up outside my garage, so they don't ask anymore.

I'm going to give it a couple of weeks and then recheck the compression. I did check the smooth running values and interestingly enough the high value had moved from cylinder 2 to 1. The other five were within normal range. I want to give the fresh oil time to do its thing and possibly move more carbon out of the rings. If I'm still getting low readings I may try again. If that doesn't do it, I'll probably swap in a low mileage engine.

[Fifty150hs]

I was finally able to run another compression check after the piston soak and running the engine with the secret sauce. Compression is down on all cylinders. Given that experience, I wouldn't recommend the procedure I followed if you're hoping to free up stuck/carbonized rings.

Cylinders one and two are the worst, same as before. Put a couple squirts of oil in them and compression came right up, so ring problem confirmed.

Just pulled the trigger on a "new" used motor with 65k miles on it. When I get it I'm going to prep it with new VCG, OPG and OFHG. I'll be installing the Viton in the OFHG. Put one in my current engine and it hasn't leaked a drop. I'll have a look at the cooling pipes as well and see what kind of condition they're in. I replaced the ones on my current engine not too long ago so they should be in good shape for a swap if I need to. Also will see what condition the crankcase ventilation system is in and replace that if necessary.

Plan on doing the work during my annual time off between Christmas and New Years.

[Effduration]

Originally Posted by Fifty150hs

I was finally able to run another compression check after the piston soak and running the engine with the secret sauce. Compression is down on all cylinders. Given that experience, I wouldn't recommend the procedure I followed if you're hoping to free up stuck/carbonized rings........
.

In a subsequent post (8/28/26), Fifty150hs discovered he had a blown head gasket, not carbonized rings, that were causing low compression and rough running.

I still recommend the BG EPR flush to clean carbonized rings if oil consumption is a problem.