timing chain tensioner

[FREE100KSECRET]

I have 03 X5 4.4 I have been nursing to the point of 238K and have dreaded the time the chain guides go, but here is my question. I have rough idle suddenly, a little rattle at cold start, smooths out above 2K RPM. Throughs code PO0011, along with misfires fuel shut off on all cylinders on bank one, so obviously the first thing I changed was Cam Sensor, no difference. I used endoscope and guide looks good, but I did push on chain and it is looser than it should be as I recall. So my question is, would a chain tensioner cause these codes? I have never had any issues with engine, so it is original, and having searched around, I see it should be replaced at 100K intervals, so anyone know if a weak tensioner can through these codes, or is it a VANOS issue more likely.

Thanks,

[Loperamide]

Originally Posted by FREE100KSECRET

I have 03 X5 4.4 I have been nursing to the point of 238K and have dreaded the time the chain guides go, but here is my question. I have rough idle suddenly, a little rattle at cold start, smooths out above 2K RPM. Throughs code PO0011, along with misfires fuel shut off on all cylinders on bank one, so obviously the first thing I changed was Cam Sensor, no difference. I used endoscope and guide looks good, but I did push on chain and it is looser than it should be as I recall. So my question is, would a chain tensioner cause these codes? I have never had any issues with engine, so it is original, and having searched around, I see it should be replaced at 100K intervals, so anyone know if a weak tensioner can through these codes, or is it a VANOS issue more likely.

Thanks,

Are you still on original guides? Is that 238k miles or kilometres?

Which endoscope did you use? I tried one that connects to my smart phone but it was very difficult trying to get the camera in the correct postion to see the guides. Am I doing something wrong? Did you do it through the oil fill cap?

As far as your other questions regarding the codes I have no idea.

[andrewwynn]

if the chain is loose the cam can snap forward and back. The lobes on the cam will push the cam advanced when it snaps over the peak. The chain is not necessarily tight without oil pressure but the spring inside gives a little base pressure so it's not sloppy loose when first started.

The best way to confirm guides didn't break (because very hard to see the left side) is to look in the oil pan.

I would drain the oil and remove the level sensor. You will be able to see in there and the endoscope will work great.

No plastic bits you're Golden and just need to replace the tensioner. Most guide failure is from people waiting too long to change the tensioner.

I would not run the engine until confirming yes/no on the guide bits. You could take a bit of a gamble just replace the tensioner (OEM only should be about $70 Amazon). Make sure to get a crush washer and it's a trick fit on the 19mm = 3/4" head the AC compressor is in the way.

A med depth socket with a short extension works or a through hole socket with extension


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[FREE100KSECRET]

Thanks a million, appreciate the insight. I did manage to get the tensioner out, what a pain with so little clearance. So it was very weak spring, so I assume that is not what is needed to keep chain tight. I looked in oil filter housing, no pieces, so will replace tensioner and see if that is issue. I am keeping fingers crossed, if it solves problem it would make me very happy, hate to think about doing guides at this stage of vehicles life, but I love the X5.

[andrewwynn]

The spring only is for the first few seconds into oil pressure builds. The bigger problem is when engine is under power and not enough real pressure.

I've helped a guy that caught this just in time and it sounds like you have very similar symptoms. The key being that the main rattle disappears at idle as oil pressure builds.

I haven't found in manual etc what is the BMW take on service life but I would use 60,000 miles on the M62.

The N62 uses a different system not so fragile and I think the m54 might use similar.

[FREE100KSECRET]

Thanks, I didn't realize until I pulled old one out that the spring action is only important upon start up and then oil pressure takes over. So that would explain the brief knocking only once in a while when starting and then noise would vanish. So given that, do these fail to pump up due to no oil pressure in unit. Enough so that there is no noise, but throws all those codes for that bank, misfire, fuel shut off along with the PO0011 code.

It would reason based on the noise people mention even after running and warming up. So wouldn't it always be noisy if it was a unit failure issue with oil pressure not building up properly. Just trying to understand if units which do not build up oil pressure are sometimes quiet while they still throw codes.

[andrewwynn]

I think the normal case is that the tensioner wears and oil leaks between the piston and cylinder so doesn't provide proper tension. You will notice it takes longer for chain noise to fade on start up and if ignored, you hit a bump while driving and the chain is slack enough to slap the guides and they shatter. If that happens it will sound like you are using the engine to polish rocks.

If chain is loose typically bank one cams will spring advanced when the lobes get past center. Only a couple will be lined up with the sensor notch on the reluctor wheel so you could possibly get a particular cylinder error but typical error is cam too advanced bank one.