[itsdude888]

Hey everyone,

I’ve got a 2016 F25 X3 xDrive28i (N20) with ~135k miles. I’ve been going through the car and wanted to get some opinions on engine health based on a recent inspection.

I pulled the spark plugs and coils and used a borescope to inspect all 4 cylinders. I recorded videos for each cylinder and will link them below.

I also performed a leak-down test not long ago — all cylinders came back under 10%.

What I’m looking for feedback on:

The vertical scoring/lines on the cylinder walls — are these typical for this mileage, or signs of abnormal wear?
The dark perimeter around the valve edges — does this look like normal carbon buildup, or potential burning?
Overall, does anything stand out as a red flag or early sign of failure?
Given the leak-down results (<10% across all cylinders), would you consider this engine healthy?

Context:

Engine runs fine overall, no major misfires
No knocking or obvious abnormal noises
Trying to decide whether to just keep driving or proactively plan for deeper work

Cylinder1 Plug & Coil
Cylinder1 Piston

Cylinder2 Plug & Coil
Cylinder2 Piston

Cylinder3 Plug & Coil
Cylinder 3 Piston

Cylinder 4 Plug & Coil
Cylinder 4 Piston

Appreciate any input, especially from those familiar with higher mileage N20s or who’ve seen failing vs healthy examples.

Thanks 👍

[bmwww_support]

I'm in the same yacht, I would say boat but its a yacht, lol.

I placed our X3 on parking insurance and we are driving a less headache/low mileage vehicle until money is real good to be able to make more repairs on the high mileage X3's we own.

Ignorance is bliss, we all heard of this statement, I don't want to find out how the engine looks internally.

At the end of the day, ask yourself, how much money are u willing to spend? does it make sense (in your own world(lifestyle))....

Sometimes its better to buy a newer X3 and use your current 2016 as a daily beater, cars take up space at home, you have to look at all factors.

If I were you, I'd put aside money for a timing chain/motor rebuild, if not, a newer X3 and limit the amount of driving being done on ur current X3, I hope this helps. Take care. Stack money, keep god first.

[qx]

didn't watch the whole thing and not a mechanic but the valves look like they close, stems are clean, and crosshatch looks good despite what seem to be very shallow vertical scoring. also nothing looks steam cleaned.

are you worried about blue smoke or burning oil? maybe the turbo drain line, if so. read they are kinda hard to replace.

if you aren't having trouble maybe don't try to fix it i guess you could spend all weekend doing a b12 soak or risk running vrp oil which has too low hths, if you think carbon is a problem.

a bottle of techron is a low risk feel good. i did crc gdi twice and the second time made it mad for a bit.

realistically are you repairing/replacing anything this deep, even if it breaks? from here you can't see bearings, failure of which would be the likely cause if these parts got damaged down the line, as i understand it.

change the oil enough, fix any upper oil leaks, don't overheat it.

signed from my armchair

[tracer bullet]

Agreed it looks good, I wouldn't touch it.

(Also not a mechanic but did work in a place that made Diesel engines for a decade and saw a lot of warranties).

You could check compression too but if it looks clean and the leak-down results are good I'd expect it to be fine too. If it is running strong button it back up and just mind the normal maintenance.

[tmsperformance]

All cylinders look good, crosshatching is still present and with minimal leakdown. The carbon looks actually very minimal for 135k as well.

I would say all is well but if you want a bit of peace of mind, get a bottle of seafoam with the spray nozzle. Place the plastic hose in the throttle body coupler and slowly spray it while revving the engine a bit. This will cause a huge smoke show and a horrible smell but it will ultimately clean your intake manifold runners, valves, piston crowns and the catalytic converter. Think of a chemical steam cleaning.

You will have a CEL OFC, so just reset everything afterwards and enjoy!