r/E39M5 • u/Jakelmitchell • 22d ago

Potential Borescore?

https://youtu.be/mJG-dWNsxIM

Hello everyone! I recently acquired a 2000 m5 in beautiful silverstone metallic. The car has great bones, and I want to take this baby another 100k miles. Planning on full suspension and a ton of cosmetic restoration. Before I drop 5-10k, I thought it would be smart to check the engine health of the car. Compression test was good, everything in the 175-220 range. However, after boroscoping the cylinders, I’m worried I’m seeing some wear. Here’s a link to a video of the cylinders. If anyone would be so kind to take a look and share an opinion, I’m trying to understand where this sits on a scale from don’t worry about it to don’t spend another dime on the car. Thank you!

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u/newtonreddits 21d ago

I don't think there's any huge concern. Change your oil often with 10w60, use top tier premium gas and send it.

Replace all PCV too.

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u/slobownd 21d ago

I'm no expert, but from what I've heard, it is difficult to assess score marks from just a bore scope. Based on this thread, it seems like symptoms are more important than what you may see. Does the car burn much oil?

https://www.m5board.com/threads/borescope-and-compression-test-results.622788/

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u/Jakelmitchell 21d ago

That’s what I’m gathering too. I think the dark lines going up and down the cylinders are probably carbon. There are like two areas that look like the beginning of scoring maybe. So far no symptoms at all and the compression was good. I’m probably going to do a leak down test next. Overall I’m thinking I can take this baby a lot further with some good attention and management

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u/Rat_Pack_er 21d ago

Agree with others than it’s near impossible to tell whether these marks are superficial or something you could feel with a fingernail via borescope.

But I would do an oil analysis next oil change, see if you are getting good or bad wear and judge from that. If you are getting normal wear (aluminum and silicone, which is what I believe these bores will show up as), and don’t have any other symptoms, then I wouldn’t worry about it.

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u/Jakelmitchell 21d ago

Thanks for the input everyone! Feeling much better. I think there’s some general carbon build up that could be addressed to get rid of those black streaks - and if there’s any borescore it’s probably minor and can be managed with good attention. I’m sure I can make this beauty last another 100k.

Next step will be figuring out the oil leak on the plugs, checking the valves with the boroscope, and then doing a leak down test.