Quote:
Originally Posted by David D
From what I've read, it sounds like classic timing chain and ramps. Combined with the mileage (114K), I'm betting that's it. I was hoping someone on here could either confirm or give me other possibilities. I got a line on a good indy shop started by a couple of BMW master techs that left the local dealership to start their own place. I want to give them a call and get a rough idea of what the cost is going to be. I know it won't be cheap...
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I can hear the cold start sound. Does sound like timing chains/guides but sounds can be misleading. The other videos can't tell.
The auxiliary air pump can sound like that but that goes away after a minute or two on 'cold' starts. One thing you can do is see if you can pinpoint the sound with an auto stethoscope, a long extension or anything that you can put to your ear and the other end around the engine. Places to to check are on the upper timing chain cover of course, water pump housing, anywhere a shaft is turning. Also front to back on each side of the engine if it is a ticking noise when engine is warm. Sometimes getting underneath can help but you will have to remove the plastic splash shield. Start on top and see what you find.
This is one of several videos about timing guide failure. Depending on the degree of failure the sound will vary. As posted in the comments, you can pull the lower oil pan to check for timing guide material or metal filings. I do that ever other time I change the oil even though there is no engine noise.
https://www.youtube.com/watch?v=I6GG9agUUdQ