Engine noise/Rattle.

J

Jamie25

Member
 Gloucestershire
I've been experiencing some new noise from my engine bay and not in a good way. The following post is quite lengthy but I've done my best to describe the symptoms and history of the car. I've done a lot of searching on here but I'm sticking to think of a likely cause. I'm hoping someone can help.
2003 3.0i M54, 90k miles.
In lower revs when taking up drive I sometimes get a random light knocking noise. Similar to tappet noise but with no notable rhythm.
About 24k miles and two years ago when I got the car I replaced the Ccv system, OFHG, vanos seals and rocker cover gasket. It has FSH and last had a change of oil in March.
Yesterday I checked the operation of the disa and it works fine. Unplugged and went for a short drive, noise still present. Also cleaned out throttle body which was pretty good anyway.
I did note that the rubber boot connecting the plastic pipe that houses the maf, the throttle body and sound generator is degrading and could be causing a leak.
There is also more 'air movement' noise than I recall and this seems to be coming from the intake side of the engine, loudest on the centre two cylinders where the Disa sits. Doesn't appear to be from the boot mentioned above.
Noted that the brake vacuum line has partially collapsed on itself and slightly flattened.
From other posts on here I'd be thinking Vanos but as I did the I6Automive kit two years ago I'd be surprised and it still pulls well enough through the rev range.

Could this all be caused by a leaking boot? Wouldn't that be nice. Thoughts anyone?
 
Realised I've put this in the wrong section.

Just got my code reader back from a friend and plugged it in. It has the following code stored. I removed them and they reappeared on the drive to work, 20+miles.

P0056 - HO2S Heater control circuit (back 2 sensor)
P1620 - Map cooling control circuit signal high
P1551 - Disa control circuit electrical.

I shall research these now.
 
I can't help I'm afraid, but I would hope that, as you have identified the degraded rubber boot and the collapsing vacuum pipe, you will be replacing these? Sometimes faults are a combination of small issues that interact. No point in trying to fix one problem if you still have other potential ones in there too.
 
Mine was a split rubber boot (behind mass sensor) sounded like tappets had gone crazy
Fitted new boot engine now runnings like a sewing machine
Could never work out why such a noise could be caused by spilt rubber
 
RRob, that video sounds just like mine although mine doesn't sound that bad.
Hopefully replacing the boot will sort it then.
And yes, the image posted by ph001 is the boot in question for me.
Looks like I have some other issues with the fault codes but perhaps the new boot will sort the disa related code.
 
How much was the boot and where did you order it from. Hope this solves the issue, keep us informed :thumbsup:
 
firebobby said:
How much was the boot and where did you order it from. Hope this solves the issue, keep us informed :thumbsup:
Click to expand...

Was the same price from Amazon and local BMW dealer at £29.60. Went for Amazon just because I should get it sooner as I'll struggle to get the the dealer next week when they'd have it in.

I'm hopeful it'll sort the first (P0056, lambda sensor) and last codes (P1551, disa fault) but I'm not sure how it'll be linked to the middle (P1620) one as that's related to the thermostat as far as I can tell.
 
Last night I took the disa out again and used some gasket sealant around the red 'o-ring' that seals it in place. It's not really an o-ring and I don't think it's replaceable on its own hence the sealant rather than replacing the whole unit.
I did this because I'd noted it felt flat and dried out, plus the sound of what I think is excessive air movement was coming from roughly this area.
Left it to sit or set overnight. This morning I cleared the three codes before turning the engine on. Previously they'd all returned after starting the engine but after my 20+mile commute, no codes! :thumbsup: :thumbsup: :thumbsup:.

Couldn't detect any rattling either but it's rarely been present at idle and only easy to hear when sounds are reverberated by walls/banks etc.

I'll obviously still fit the new boot when it arrives but fingers crossed it should be sorted.

So if anyone gets the knocking noises like the video posted by RROB or the codes P0056, P1620 and P1511, then it's worth checking the disa valve seal is still doing its job!

Cheers for all the comments and help folks.
 
Reviving this old topic - but did the new boot sort your issue?

I have a noise exactly like Rob posted in the video.

Will be relieved to know it is a simple fix!

Thanks,
 
GengisKaan said:
I have a noise exactly like Rob posted in the video.
Click to expand...

out of curiouity, have you checked the sound generator piping? i just fixed my rattle today, after 1 year of dealing with it :rofl:
 
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