What the heck is this noise?
 

Hey people,

This noise (ticking) I have been trying to figure out for a while (attached the video) which seems to be coming from the driver's side of the engine. I thought it was coming from the top of the engine but it's as loud towards the bottom.

https://www.youtube.com/watch?v=PWK_...ature=youtu.be

I have replaced that side of the lifters. Also, replaced spark plugs, checked out coils. I have even replaced the injectors since I thought the noise was coming from there after I listened with a stethoscope.

The noise does not start immediately after a cold start but it seems to become very obvious after the secondary air pump stops working. Would it have something to do with that? (I do get a secondary air injection error very frequently) Also, it subsides after I rev up the engine.

I have visited my old mechanic and he said that it was probably rod knocking / rod bearing. I listened to many rod knocking sounds and what I hear does not match any of them I heard.

Any opinion / help will be greatly appreciated..

Thanks,

Ozzie

To eliminate if it is from a rod knock, you can disable the cylinder so that it is not producing any power. If the knock goes away you just found which cylinder has the rod knock. This test is just to determine if you have a rod knock. Do not drive around with the cylinder disable.

Is it safe to unplug a coil and start the engine and run it briefly?


Thanks,


Ozzie

Yep, or can you have the engine running and unplug each coil connector. Do not pull the coil off the plug.

Thanks, I am also reading this noise may have something to do with the secondary air ports getting clogged because the ticking starts happening after the secondary air pump stops working..


Any opinion?


Thanks,


Ozzie

How full is oil and what grade? I would do the tests cylinder by cylinder to determine if one is at fault.

I suspect not enough lubrication backed by the revs clear it (more rpm more oil pressure). Also coincidentally the thicker cold oil stays in channels with less pressure. Does your oil light go off quickly at start (I have 3.0 but if it takes more than 6 sec. to clear the oil light I'm very low on oil.


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Oil is Castrol 5W40 (ll01) and just filled it up. There is no oil light staying at startup. There used to be until I fixed the valve issue inside the oil filter housing.



I will do the cylinder testing tomorrow probably..


Thanks,


Ozzie

So I unplugged each coil to see if the ticking would go away. It is still there. Does that eliminate the rod knock problem completely or would there be still a rod bearing issue?


I am planning on taking the pan down today to take a look..


Thanks,


Ozzie

Is there a way with OBC to read oil pressure. I suspect a oil delivery issue. You may see telltale with the oil pan off. (something you can reasonably do on the 8: have to remove the CV axles on mine).

Also: when you re-attach the stiffening plate be advised they are held on with single used torque to yield bolts. You can reuse them sensibly if you use half the torque angle. Preload to 60 N·m then turn 45° vs 90°. In testing they fail after about 3-4 full tightening processes.

I have yet to work out the exact values partly because I'm upgrading to larger bolts that achieve the same grip at normal torque (unlimited re use). But as I retire my old bolts I plan to do more destructive testing to make some determination on a decent compromise between throwing out $120 worth of bolts and throwing out the function of the aluminum plate (stiffening the entire body of the car)

You still can't see easily the crank on the V8 - while the pan is split (upper and lower) the upper pan is mostly similar to the pan on th I6 in that it blocks access to the bottom end and has the front axle running thought it....

But you can easily pull the lower pan to check for debris, foreign objects etc.

I pulled the oil pan over the weekend. There was a lot of slush but no copper / metal particles. Also the oil pump pipe was mostly clogged with gunk which I cleaned up thoroughly. There were a couple of very small plastic pieces in it which I suspect is from the timing chain guides which I may look into later.



Meanwhile, I still have that darn tick. Not sure what else to look at at this point.



Thanks for all your help / opinions..


Ozzie

I think you found your source of the tick, you need to replace the timing guides.

I thought about that but pieces very little and wouldn't a chain guide noise have higher frequency rather than low frequency ticking?


Thanks,


Ozzie

Thank you for the link. It certainly has great info. I may have to go towards that direction but the biggest plastic piece I found was 1 x 2mm which came out of the oil pump pipe. Would there be a way to look in there without opening it up completely? Maybe a borescope thru the oil cap?


Thanks,


Ozzie

The fact that you found plastic in the oil pan is already definitive proof that the chain guides are failing. Even if you don't think that is the source of noise it is still something that has to be addressed SOONER and not LATER.

Boroscope through the oil cap is exactly how to look at the chain guides. You can see the main pressure guide right inside the hole.

If you only have tiny pieces my question is: have you replaced the main tensioner and part b did you use OEM?

My research shows lack of replacing the tensioner is the primary cause of chain guides fail on M62.

A buddy of mine's M62 sounded a lot like yours my advice was to drive a different car and order OEM chain tensioner immediately.

He installed the new one and heard the diesel sounding chain clank for about 7 seconds until oil pressure built up in the tensioner and now it sounds new. No clank no diesel knock sound.


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I totally agree with you on that. Car is at 200k+ and it will have to be addressed eventually but I guess I am trying to avoid lengthy repairs right now..


Thanks,


Ozzie

I did indeed. I replaced the old one with the new redesigned one some time ago although I am not so sure if it were the OEM but very likely it is. Would the OEM make a big difference?


Thanks,


Ozzie

The chain tensioner is an exceedingly important part to the survival of the chain guides and I wouldn't trust non OEM at all. OEM will cost 2-4x as much as knock off about $60 I think.

The prob with knock off is it won't hold the oil pressure so won't hold the chain as tight so the chain will slap. The slap is what kills the guides.

If you only have tiny bits I would use boroscope to determine where it came from. I think you might gain access from the vanos solinoid hole or can sensor hole to get a good look at things without removing the valve covers.

When the guides catastrophically fail it will sound like somebody poured gravel in the engine and if you cut the power soon enough the chain won't break and you can replace the guides so causing significant damage.

When the tensioner is replaced regularly you can typically get over 200,000 miles on the V8. Don't change and for sure by 160,000 you'll be doing chain guide job.

If I had the V8 and was making that sound I would replace the tensioner with OEM regardless of how old or what brand is currently in there.

If the sound goes away at higher RPM I think the problem is oil pressure related.

Either not enough oil pressure in the crank area or not enough pressure inside the tensioner.

If you found bits of chain guide that weighs the odds heavily in favor of tensioner is the problem, else I would suspect the oil pump is not providing adequate pressure at low RPM.

I am almost positive I bought an updated OEM. I think I paid around $90 for it. I have found a very tiny piece of rail (1mm x 2mm, I think it was a corner) and a lot of gunk and maybe some gasket material blocking the oil pump pipe screen which I cleaned thoroughly.



Right now, I only have that tick (and some vanos noise) which seems to be quiet at idle, gets louder a little when I rev and disappear after 1500-2000 rpm. I just got a oil pressure tester and a boroscope to check things. If I see low oil pressure, I may take the pan down again and apparently there is a check valve that may affect the pump's performance?


Once again I appreciate all the help,


Cheers,


Ozzie

What the heck is this noise?
 

Double post

Done oil pressure test today and it was first at 20 psi and settled around 15 psi on idle and went up to 50 - 60 psi at 3000 rpm.


I am guessing those numbers are normal?


Thanks,


Ozzie

What's interesting is, the ticking does not start immediately. The engine is very quiet after the cold start for a minute or so. After that the ticking slowly becomes loud.


Should I go back to the lifters and replace them with new ones? Last time I simply cleaned them up and put back in..


Thanks,


Ozzie

With a stick stethoscope can you lock into a cylinder?

Also the not when cold is almost certainly because the oil is thicker at start


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I listened all around the engine with a stethoscope and I thought it was actually coming from the injectors. It even seems to spread towards the bottom of the engine. That is why some thought it'd be rod knocking but it does not have that metal sound of the knock and I already did the cylinder testing (pulling each coil) to eliminate that and I am guessing a rod knock could still be heard when engine is cold..



I am trying to put the boroscope camera thru the oil cap to see if I can see anything but I could not succeed on that yet..


Thanks,


Ozzie

What the heck is this noise?
 

I'm wondering if you can also get a boroscope though either the cam position sensors or the vanos solinoid port.

On the M62 you can check out quite a lot with a boroscope through the oil fill hole (also known as the oil ejection port if your run the engine with the cap off)

Check your chain tension through the oil fill port using something like the rubber covered handle of a pliers. If you test right after shut down I suspect it should be stupid tight. I don't know how long it takes for the tensioner to loose operating pressure.

Here is another theory.


I have been reading BMW actually replaces the cylinder heads (if under warranty, of course) to fix this problem. So, I am guessing the problem is with the heads which lead me to think that the tiny oil ports that go to the lifters etc. may be blocked or not functioning well? The oil pressure will still look good and you can replace the lifters to the new ones but when there is no enough oil supply, the ticking will continue..


If that is the case, how can we clean those ports without pulling the engine apart physically?


Any ideas?


Thanks,


Ozzie