N47 timing chain
Discussion
My wife a has F25 X3 which has a N47 2.0d engine.
I have noticed that there is a slight knocking noise which is most evident on idle. If I touch the throttle pedal ever so slightly the noise goes away. I literally have to increase revs by about 100rpm.
I pulled the engine cover off today and noticed the you can see the airbox and other bits vibrating. Again if I increase by 100 revs it stops.
Here is a video. https://drive.google.com/file/d/1xNnHsFOW2r5I2jXVR...
Is this normal? Little worried as I know these engines have timing chain issues.
Thanks
I have noticed that there is a slight knocking noise which is most evident on idle. If I touch the throttle pedal ever so slightly the noise goes away. I literally have to increase revs by about 100rpm.
I pulled the engine cover off today and noticed the you can see the airbox and other bits vibrating. Again if I increase by 100 revs it stops.
Here is a video. https://drive.google.com/file/d/1xNnHsFOW2r5I2jXVR...
Is this normal? Little worried as I know these engines have timing chain issues.
Thanks
Timing chain rattles (usually a tension issue) have a tick that increases with revs.
You might have an issue like a failing engine mount, could be some heat sheilding thats vibrating (things can harmonise at particular frequencies and vibrate, then as the engine revs rise and the frequency changes, the harmonising offender stops doing it's thing, noise stops).
A rumble could also be something bottom end, but you'd like to think that the noise would vary with engine revs as well. In any case, its worth just making sure the oil level is correct. If you havnt changed it in a while (let's say the last 8000 miles) then it might be worth changing, along with a new filer (i know BMW like to specify long oil cange intervals, but it doesnt hurt to reduce that interval if you are intending on keeping the vehicle a long time). You can send away samples of oil for analysis, which ight indicate excess metal in the oil suggestive of some deepr enigne issues (for example, bottom end troubles) but a noise like this wouldnt suggest that.
I suspect it's something not overly sinister. If there is a timing chain issue (the timing chain has stretched, or example) then this can be checked by careful measurement between a set number of links (there is tolerence engineered in to account for timing chain stretch over time). I understand the timing chain issues with the N47 engine were due to poorly manufactured crankshaft sprockets. Being a later model N47 engine though, I would hope you have one where these issues were ironed out.
Best of luck hunting it down.
You might have an issue like a failing engine mount, could be some heat sheilding thats vibrating (things can harmonise at particular frequencies and vibrate, then as the engine revs rise and the frequency changes, the harmonising offender stops doing it's thing, noise stops).
A rumble could also be something bottom end, but you'd like to think that the noise would vary with engine revs as well. In any case, its worth just making sure the oil level is correct. If you havnt changed it in a while (let's say the last 8000 miles) then it might be worth changing, along with a new filer (i know BMW like to specify long oil cange intervals, but it doesnt hurt to reduce that interval if you are intending on keeping the vehicle a long time). You can send away samples of oil for analysis, which ight indicate excess metal in the oil suggestive of some deepr enigne issues (for example, bottom end troubles) but a noise like this wouldnt suggest that.
I suspect it's something not overly sinister. If there is a timing chain issue (the timing chain has stretched, or example) then this can be checked by careful measurement between a set number of links (there is tolerence engineered in to account for timing chain stretch over time). I understand the timing chain issues with the N47 engine were due to poorly manufactured crankshaft sprockets. Being a later model N47 engine though, I would hope you have one where these issues were ironed out.
Best of luck hunting it down.
thatdude said:
Timing chain rattles (usually a tension issue) have a tick that increases with revs.
You might have an issue like a failing engine mount, could be some heat sheilding thats vibrating (things can harmonise at particular frequencies and vibrate, then as the engine revs rise and the frequency changes, the harmonising offender stops doing it's thing, noise stops).
A rumble could also be something bottom end, but you'd like to think that the noise would vary with engine revs as well. In any case, its worth just making sure the oil level is correct. If you havnt changed it in a while (let's say the last 8000 miles) then it might be worth changing, along with a new filer (i know BMW like to specify long oil cange intervals, but it doesnt hurt to reduce that interval if you are intending on keeping the vehicle a long time). You can send away samples of oil for analysis, which ight indicate excess metal in the oil suggestive of some deepr enigne issues (for example, bottom end troubles) but a noise like this wouldnt suggest that.
I suspect it's something not overly sinister. If there is a timing chain issue (the timing chain has stretched, or example) then this can be checked by careful measurement between a set number of links (there is tolerence engineered in to account for timing chain stretch over time). I understand the timing chain issues with the N47 engine were due to poorly manufactured crankshaft sprockets. Being a later model N47 engine though, I would hope you have one where these issues were ironed out.
Best of luck hunting it down.
Thank you, great reply.You might have an issue like a failing engine mount, could be some heat sheilding thats vibrating (things can harmonise at particular frequencies and vibrate, then as the engine revs rise and the frequency changes, the harmonising offender stops doing it's thing, noise stops).
A rumble could also be something bottom end, but you'd like to think that the noise would vary with engine revs as well. In any case, its worth just making sure the oil level is correct. If you havnt changed it in a while (let's say the last 8000 miles) then it might be worth changing, along with a new filer (i know BMW like to specify long oil cange intervals, but it doesnt hurt to reduce that interval if you are intending on keeping the vehicle a long time). You can send away samples of oil for analysis, which ight indicate excess metal in the oil suggestive of some deepr enigne issues (for example, bottom end troubles) but a noise like this wouldnt suggest that.
I suspect it's something not overly sinister. If there is a timing chain issue (the timing chain has stretched, or example) then this can be checked by careful measurement between a set number of links (there is tolerence engineered in to account for timing chain stretch over time). I understand the timing chain issues with the N47 engine were due to poorly manufactured crankshaft sprockets. Being a later model N47 engine though, I would hope you have one where these issues were ironed out.
Best of luck hunting it down.
My mind is a little at ease now knowing it is unlikely to be the timing chain. As you say, this should get worse with revs whereas mine the noise dissapears.
The car has got BMW warranty until end of the month so have got it booked for next week. The reason I started this thread was to get some further info because it went to the dealer last month and they said there is nothing wrong.
So the booking next week is with a different dealer, hopefully there more clued up.
As i dont want the dealer to come back with the same thing, this is why I decided to have a look myself.
Find it very strange that the airbox is vibrating as it is
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