[Ivilla035]

Originally Posted by MyBimma

This is another image … I’m assuming this is what they’re referring to being outside the tolerance.

Interesting. By the looks of that, the sludge of the oil could be the thing that closes tolerances. At the end of the day what happens when you have timing chain clanking on startup? Could be a few things, but at the end of the day it's lack of oil service degrading parts (since oil doesn't get to timing components cold). Your best option is to do a flush, and asses the situation after with how it looks. Do this before you slap a valve and blow it up.

[MyBimma]

Originally Posted by Ivilla035

Interesting. By the looks of that, the sludge of the oil could be the thing that closes tolerances. At the end of the day what happens when you have timing chain clanking on startup? Could be a few things, but at the end of the day it's lack of oil service degrading parts (since oil doesn't get to timing components cold). Your best option is to do a flush, and asses the situation after with how it looks. Do this before you slap a valve and blow it up.

Thanks for that. Will let the garage know and hopefully have it all sorted.

Appreciate your guidance - will keep you in the loop re repairs

[Ivilla035]

Originally Posted by MyBimma

Thanks for that. Will let the garage know and hopefully have it all sorted.

Appreciate your guidance - will keep you in the loop re repairs

Awesome. Do the flush yourself if you can. If you do, update us with pictures of how it looks before/after! Best of luck to you!!

[AlmondJayRoM3]

Originally Posted by MyBimma

Full service history. Prior to that was 12 months ago. But trying to figure out if it’s repairable

How many miles on your engine and did you own it since new?

I've seen an N55 and N20 engines at 200k miles and 150k miles and their insides had very little sludge and mostly varnish. These engines generally followed the general BMW service requirements usually using LL01 or Euro synthetic oils that can be purchased at Walmart.

I can only assume what might have gone wrong to cause that sludge since you say you followed the required change service intervals. Oxidative thickening that results in sludge build up is usually caused by drain intervals that are too long for the type of oil or use case. Wrong type of oil, poor quality or even running non synthetic oil at the BMW drain intervals.

Moisture/condensation or fuel contamination can also accelerate oil breakdown into sludge. This can occur with mechanical issues such as faulty injectors or failing head gaskets. Contamination can also build up due to excessively short drive cycles such as short commutes. This doesn't allow oil to get to temp and burn off moisture and fuel contamination in the oil. This is where the interval needs to be shortened because of "severe" driving conditions.

[ErkanTR16]

I have used this on several of our cars and have not had any issues whatsoever.

GF’s e90 N51 328i previous owner didn’t change the oil frequently and after doing a valve cover replacement there was some oil sludge. The engine flush worked very well for this case.

F10 N20 528i - currently at 162K miles and I used it a few times just for peace of mind.

F30 B58 340i - this is my daily since 2018 and it’s at 102K miles. Ive always changed the oil every 5K miles and used the engine flush only once.