[therealobscure]

Hi (you may have seen this post on another forum as well),

I've got an E90 330xi (2006) with about 235,000 KM. Car is bone stock, and I will try to breakdown everything we have checked. If there are any further details I should add that I have missed please ask, I am more than happy to try and answer or investigate (within my abilities). Videos will be added as soon as I am able to, likely later today.

Background

This issue has started occurring about a year and a half ago, when it first appeared we will still putting quite a few KM on it (yes this may have been foolish, but alas). Since this had started occurring, there have been a few thousand KM put on the car, which raises some questions for me with regards to diagnosis.

Many will likely say to discard the vehicle, but it has sentimental value for us now and we have already put in effort to try and diagnose the issue (and I am still unsure if the diagnosis we got was right, but maybe you guys can talk some sense into me).

Sound from engine bay.
Sound with hood closed/interior, under driver door.
Idling
The initial thought was that a rod bearing has gone/is very worn, and there is now rod knocking in the engine. The sound is pretty consistent with that for the most part, and the first mechanic (guy we typically go to for any work we aren't really able to at home) said after just a quick listen that it is likely rod knock and that the engine has like a hundred or so more KM on it. Since then, it has been driven at least 1000km (sound had been present for a while here). This was last year, around this time. This year, we had taken it to another mechanic who was willing to do some investigation on his own time (charging a very, very low rate). He believed that it may be oil pump related, and that the engine was not receiving enough oil. The car has had a slight oil leak for quite some time, but we had always been topping it up and making sure that it is topped up before driving. After investigation he said that it is likely not the case, and that it is likely that a rod bearing is worn, and that the engine is knocking from that. Now, I am fine accepting that reality, but we are just confused and would like some more input from the knowledgeable and experienced people here. I will list some things I think are important below:

Sound does not occur on cold start (to my perception)Cold Start Video

Sound immediately becomes prominent when engine has warmed up.

VANOS gears have been ruled out (and I have replaced camshaft timing positioning sensors)

AC pulley system has been ruled out (I have seen a video with an almost identical sound and that was their issue, was easy to check).

There was previously a code for the camshaft timing position sensor (which was why we had suspected VANOS before), I changed out the sensors on my own. The code was then removed for this, but did not amend the issue.

There is the code for the transfer case fluid (0054C6) present, but no mechanic suggested that this would be directly related to this issue.

Car has been driven for nearly 2000km (possibly more? I cannot remember exactly, sorry) since the problem has started. I thought that a rod knock was a near immediate death sentence which is why we are somewhat confused/asking here .

The car does not feel like performance is affected very much, if at all (and yes, while stupid, it has been revved high many times in the past year and a half).

The car does have a bit of an unstable idle, but this was made better when I changed the timing positioning sensors. Not entirely sure if it was present before this particular issue, though.

Intake has been ruled out.

Engine sounds most prominent around 2000-2500 RPM, but is present throughout the RPM range when the vehicle is warmed up (so this may just be because the engine/exhaust sound is not drowning it out at those RPMs).



I would like to know if y'all have any thoughts, or anything that I could potentially check, or if you are also convinced that it is rod related (I have pretty much accepted this). Also, I know people are likely to suggest to discard the car, but if we didn't want to, how would/could you go about an engine change for the specific 330xi E90 (afaik the intake is different than the later 328xi's and has more power? Anything else?). If anyone is around the Edmonton, AB area, or knows of a good shop around there that may be willing to undertake that, please let me know!

[therealobscure]

Videos added, please let me know if they work!

[Brian86]

With the caveat that it's really difficult to diagnosis problems over the internet with a video....

That sounds like rod knock.

Has anybody drained the oil to see if it looks like bass boat paint? If there are sparkles in the motor oil and oil filter... I'd be looking for a whole new longblock assembly.

It's possible to put rod bearings in w/o removing the engine, but all the metal circulating, and the prior oil starvation that caused the problem in the first place, has already done a ton of damage everywhere.

Metal likes to accumulate at the vanos solenoid screens and would be contributing to that problem. Pull the solenoids out and look for metal.

[therealobscure]

Originally Posted by Brian86

With the caveat that it's really difficult to diagnosis problems over the internet with a video....

That sounds like rod knock.

Has anybody drained the oil to see if it looks like bass boat paint? If there are sparkles in the motor oil and oil filter... I'd be looking for a whole new longblock assembly.

It's possible to put rod bearings in w/o removing the engine, but all the metal circulating, and the prior oil starvation that caused the problem in the first place, has already done a ton of damage everywhere.

Metal likes to accumulate at the vanos solenoid screens and would be contributing to that problem. Pull the solenoids out and look for metal.

See that's the strangest thing, and part of why I am a little confused. When the mechanic did his own investigation and pulled the oil pan, he said he did not see any metal inside. Solenoids I could try pulling again, I know we have cleaned them recently however I don't recall if they had metal shavings in them. I could attempt to pull them again.

Like you suggest, I would've imagined that after a few thousand kilometers of having a rod knock around, that there would be metal in the oil. Any other ideas?

[Brian86]

Don't know.

If there's no metal in the oil... I guess keep driving it.

Does it have a manual gearbox? Perhaps the dual mass flywheel bad and chattering around? This is totally a guess, as I have no idea.

[therealobscure]

Originally Posted by Brian86

Don't know.

If there's no metal in the oil... I guess keep driving it.

Does it have a manual gearbox? Perhaps the dual mass flywheel bad and chattering around? This is totally a guess, as I have no idea.

It is an automatic (did they come with X-Drive and manual?). We've other cars so it doesn't need to be driven now thankfully, but we just really like the thing. Been with us for a long time. Thanks for trying to help though! Hopefully some others can chime in too

Barring a full engine takedown I don't see personally how else to diagnose the issue beyond what we've tried already. People where I live that do engine rebuilds though are not keen on working on German cars however.

[Brian86]

I know how you feel. I have one that needs to go. The engine, drivetrain, and running gear are used up at 388k miles (625k km).

Picked up a VW to replace it. Some aspects I like better, some not so much.

I sure am going to miss my e9x.

[e90yyc]

Originally Posted by therealobscure

It is an automatic (did they come with X-Drive and manual?). We've other cars so it doesn't need to be driven now thankfully, but we just really like the thing. Been with us for a long time. Thanks for trying to help though! Hopefully some others can chime in too

Barring a full engine takedown I don't see personally how else to diagnose the issue beyond what we've tried already. People where I live that do engine rebuilds though are not keen on working on German cars however.

Yes, xDrive and manual were offered. Automatic transmission was optional and cost $1600 CAD for 2007 MY. (I just checked the stock card for my car…)

I’m not sure tearing it apart makes sense… I’d just look for a good used motor to drop in.