Let's play Guess That Noise - PeachParts Mercedes-Benz Forum

New2MB · #1 11-11-2010, 06:23 PM

I've been working on getting my engine (603) running again and recently decided to purchase a used IP as mine wasn't pushing fuel out of one of the DV's.

About a week ago I was cranking the car over and everything sounded great, no unusual noises.

Then I got the new used IP and installed it and at the same time I remembered that I had not primed my new timing chain tensioner so I did that as well.

I also installed a new output shaft seal on the transmission but this noise isn't coming from that area and I can't see any way that it is connected.

So today I got everything back together and cranked it over and I hear a hollow metallic sort of scraping with maybe a slight clangning. The noise is completely inconsistent, sometimes it goes away completely, sometimes it gets to the point where I think I should stop cranking. But there doesn't seem to be any relation to where in the rotation of the engine the noise occurs.

It's definately coming from the engine but I can't tell where, I tried listening for it on a mechanics stethascope that was touching the timing cover. The funny thing was that the noise was not very pronounced with the stethascope in my ears, it was much easier to hear without it which makes me think perhaps it is not internal to the engine.

I pulled the valve cover and I don't see anything out of the ordinary nor can I hear the noise any better with the cover off.

I'm not even sure where to look next but I figure it must either be related to the chain tensioner or the vac pump or some combination of the two.

Any ideas?

vstech · #2 11-11-2010, 06:28 PM

you dropped a socket or oil filler cap into the fan shroud...

New2MB · #3 11-11-2010, 06:50 PM

Oh I like that one, that would be easy.

And come to think of it, it does have the tinny fan blade scraping something type noise.

And it would explain the inconsistency of it.

That serpentine belt was a real pain until I remembered the correct routing.

barry123400 · #4 11-11-2010, 10:10 PM

You had the transmission out. Something scraping in the torque/flexplate area intermittently? It might be hard to localise from above with a stethoscope.

I have a stupid problem of this nature with an other brand car. As long as driven daily no issue. Park it a few days and it reocurrs. Park it more than a week and initially you think it should be taken apart for a look. I make sure it stays in service daily.

New2MB · #5 11-12-2010, 09:50 AM

A good guess but I didn't have the transmission out, I just pulled the driveshaft to do the seal. I'm almost 100% certain the noise is not coming from the driveshaft area.

barry123400 · #6 11-12-2010, 10:44 AM

Many things are a matter of perception and experience. Most good mechanics. Or a friend that has more automotive experience than yourself might give an opinion in person.

Since it seems to have been coincidental with the injection pump change and rear transmission seal change is a strong issue. Neither am I familiar with your car. Did you drop the back of the transmission lower to change the seal?

Also since you primed up the chain tensioner is it too tight if that is possible? Yours would have the one way ratchet advance I would think. Again I do not know if an individual could overtension it manually.

Without hearing it personally can make it harder. Did you take the chain tensioner apart and reinsert from the back? If not you may have accidentally gotten past where it was originally running. The chain tensioner did seem normal to you?

Again I am not even sure that is possible. Sorry that I do not have a eurka for you although it is possible some other member with far more experience will..

New2MB · #7 11-12-2010, 08:57 PM

Barry, you're onto something with the tensioner.

Before priming the tensioner it had much less tension and there was no noise.

After priming the tensioner it had much more tension and that's when the noise started.

Today I uninstalled the tensioner and slowly did a little hand cranking... no noise.

I put the tensioner back in and screwed it almost all the way into the block. The noise was significantly reduced.

It sounds like it's coming from somewhere in the timing cover, near the low end if I had to guess.

I thought tension was set automatically, is there something I was supposed to do to set the tension? It looks like there is a bolt on the end of the tensioner on the outside, perhaps that needs to be backed out?

I did a little forum searching and haven't found anything yet.

New2MB · #8 11-15-2010, 10:42 AM

I pulled the vacuum pump and the noise is still there.

I removed the accessory belt and the noise persists.

The noise is definately related to the amount of tension in the timing chain but I haven't found any way to change the amount of tension being applied by the tensioner.

Is it possible that if I dropped the slack in the timing chain down the wrong side of the cam gear that it would cause a noise?

vstech · #9 11-15-2010, 12:58 PM

the chain tensioner is a ratchet type design... if it's gotten slack, and fully extended, it has to be removed and reinserted to reset the tension...

New2MB · #10 11-15-2010, 05:07 PM

If it ratchet's that means that when I push the plunger in the plunger should stay in, correct?

When I remove the tensioner and push the plunger in by hand in it does not stay in, it pops right back out to fully extended.

I tried removing the cap on the end of the tensioner and it is stuck on there good, I'd need to mount it in a vice and put a breaker bar to it so I decided not to remove the cap.

The noise now is a squeak and I can hear it even while turning the engine over by hand. It sounds like something is rubbing somewhere. Maybe I'm being paranoid? Maybe my new rails need to be 'broken in'? Wishful thinking I know.

Back the tensioner out a few threads and the squeak is gone.

I can't figure out what I could have done wrong to create this. If I put a chain guide in wrong I don't see how it could have all gone back together without issue.

Maybe I need to pull the IP and see if it's in the IP. But I swear it's coming from the lower end of the timing cover.

barry123400 · #11 11-15-2010, 10:22 PM

I posted on your other thread of how does the tensioner work. About the last comment I have is if the car has the wrong type tensioner installed.

I think you stated you can depress the tensioner back a substantial distance. That would seem to indicate a non ratcheting type. Also compare the part numbers between the old and new.

If you changed tensioners because of preventative maintenance other than failure try the old tensioner in position to see if the noise is gone.

New2MB · #12 11-15-2010, 10:57 PM

I can push the plunger all the way in, by hand even.

I thought it was harder to push in after I primed it, maybe it lost its prime.

I'm about ready to drill a hole in the oil pan or timing cover or disassemble my cell phone and drop the camera part down into the engine just to see what the hell is going on.

I can't even think of what could go wrong to create this, nothing, I'm totally stumped.

I mean even if I did have too much tension in the timing chain, what would be squeaking?

There's no damage to the chain, there's no plastic pieces from guide rails, no damage to the vac pump gear, arrrgh!

soothappens · #13 11-15-2010, 11:22 PM

Quote:

Originally Posted by New2MB

I've been working on getting my engine (603) running again and recently decided to purchase a used IP as mine wasn't pushing fuel out of one of the DV's.

About a week ago I was cranking the car over and everything sounded great, no unusual noises.

Then I got the new used IP and installed it and at the same time I remembered that I had not primed my new timing chain tensioner so I did that as well.

I also installed a new output shaft seal on the transmission but this noise isn't coming from that area and I can't see any way that it is connected.

So today I got everything back together and cranked it over and I hear a hollow metallic sort of scraping with maybe a slight clangning. The noise is completely inconsistent, sometimes it goes away completely, sometimes it gets to the point where I think I should stop cranking. But there doesn't seem to be any relation to where in the rotation of the engine the noise occurs.

It's definately coming from the engine but I can't tell where, I tried listening for it on a mechanics stethascope that was touching the timing cover. The funny thing was that the noise was not very pronounced with the stethascope in my ears, it was much easier to hear without it which makes me think perhaps it is not internal to the engine.

I pulled the valve cover and I don't see anything out of the ordinary nor can I hear the noise any better with the cover off.

I'm not even sure where to look next but I figure it must either be related to the chain tensioner or the vac pump or some combination of the two.

Any ideas?

I'm getting the same noise almost word for word out of my 617 in the 81.

I was going to post and ask about it but had no idea how to word it. I also pulled valve cover, vacuum pump and belts. The stethoscope was of no use on mine either. The noise comes from low in the block no rhythm almost like a chain on a ten speed when you pedal it backwards only more pronounced.

Through lots of searching I came across one on the oil pump chain getting slack. The outcome was a broken chain and a destroyed engine.
Not sure if the 603 has a chain on the oil pump but that's what I started searching the forum for on my 617.

The only symptoms I found where on the thread with the damaged engine.
The noise was present and they noticed the oil pressure gauge dancing around.

I wish I could remember the thread.

New2MB · #14 11-15-2010, 11:38 PM

The oil pump chain had been nagging at the back of my mind because I just replaced it and the tensioner.

However, I can make the noise go away by backing my timing chain tensioner out a couple threads so I'm fairly certain it is related to the timing chain or something it touches.

I can't think of any way that the timing chain would effect the oil pump chain.

And my oil pressure is steady, no bouncing that I've noticed.

soothappens · #15 11-16-2010, 12:30 AM

Quote:

Originally Posted by New2MB

The oil pump chain had been nagging at the back of my mind because I just replaced it and the tensioner.

However, I can make the noise go away by backing my timing chain tensioner out a couple threads so I'm fairly certain it is related to the timing chain or something it touches.

I can't think of any way that the timing chain would effect the oil pump chain.

And my oil pressure is steady, no bouncing that I've noticed.

I just looked at the other thread on the tensioner.
It seems the tensioner is filled with oil and the pressure is regulated by the springs pressing against the 2 check balls.
The oil then bleeds out port B to the pan. Basically a small shock or accumulator.

The only way I see it over pressurizing would be if the B port is blocked
or partially blocked. This would give you full oil pressure in the tensioner. It would also block any means for the oil to escape.
The piston would not retract eliminating the shock function making it into a solid piece of metal.
This would maintain until the pressure bled off. You backing it out a thread relieves the pressure.

Maybe a piece of trash stuck in the B port ?