Knocking sound under acceleration uphill, with bluish smoke from the exhaust

Tiny
LEROS
  • MEMBER
  • 2008 BMW X3
  • 3.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Failed water pump, replaced. Failed kick-starter, replaced. Failed battery, replaced. Now car stalls incessantly. Changed oil and plugs to see if will resolve, now car develops a slight knocking sound under acceleration uphill, with bluish smoke from the exhaust. Now knocking sound is loud and will sound out when car is in park.
Thursday, March 19th, 2020 AT 10:49 AM

2 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Unfortunately, blue smoke is burning oil and the knocking is a bearing issue and it will only get worse. The engine is going to need to be completely disassembled and either rebuilt or replaced.

Clearly a knock is not good so may getting a video of the noise just so we can confirm that this is what it is going to need before you go too far.

https://www.2carpros.com/articles/blue-smoke-from-engines-exhaust
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Thursday, March 19th, 2020 AT 2:02 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Blue smoke is usually an indicator that oil is being burned. By any chance, was the oil over filled when you changed it? Also, is it possible for you to record the sound you hear from the engine and upload it for me to hear?

https://www.2carpros.com/articles/blue-smoke-from-engines-exhaust

One other thing. Have you tried pulling codes from the computer to see if any are present?

Here is a quick video showing how it is done:

https://youtu.be/YV3TRZwer8k

I realize most people don't own a scanner, but often times a parts store will do it free of charge or lend/rent you a scanner.

As far as the stalling, have you checked fuel pressure and if there are any vacuum leaks?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know.
Joe
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Thursday, March 19th, 2020 AT 2:03 PM

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