87 300d noise, rod or lifter? - PeachParts Mercedes-Benz Forum

ajnorris · #1 10-29-2010, 07:19 AM

So I bought my first diesel (87 300d) a few months back and after letting it sit in the driveway for a few months I got some time to work on it. Being new to diesels I didn't think much of the various clacking noises. I pulled the injectors, pop tested them (numbers and spray pattern looked great), updated the vaccum pump swapped out the bad belt bracket assembly and a bunch of other little stuff. I did a compression test and got some low scattered numbers (200-360psi) but since i did it cold (ie engine hadn't run in months) and I may have left the heat sheild out on one cylinder i figured I'd repeat it once I got it running. Now after reading more posts I'm a little worried. There is a moderatly loud tick/clack noise. I have had a hard time isolating exactly where it is comiing from and it doesn't go away with higher RPM or cracking the injector lines. Was hoping it might be a lifter. Another thing I should not is that it lets out a pretty good puff of white smoke (smells like diesel, not coolant) when started cold and I noticed one of the prechambers was slightly wet when changing the injectors. Can I just pop the valve cover off and look for a collapsed lifter? By the way it has the #14 head but no signs of cracking yet. I just don't want to put more cash into it if the bottom end is toast. I found a #18 head cheap and have it on the shelf for a rainy day. Any advise would be greatly appreciated.
Thanks,
Ashley

layback40 · #2 10-29-2010, 07:55 AM

sounds like a lifter from what you say. After a motor has sat, they can be noisy for a while. Some oil brands are claimed to help. How bad is the noise? My 2.5 rattles a little if it is let to idle straight after a high speed trip.

vstech · #3 10-29-2010, 12:26 PM

what is this "bad belt bracket assembly" that you changed?
the tension assembly/shock and bearings are known to cause a rattle that is hard to isolate, but I think this is what you changed, could you clarify?

ajnorris · #4 10-29-2010, 04:51 PM

It sounds like sort of a steady constant clack that varies with RPM. It is about due for an oil change. You can faintly hear it inside the car but outside it is easy to hear when rev'd above idle. I'll try to post a video on youtube shortly.At idle it is not very discernable over the slight combustion knock. It does it all the time, hot and cold. I've been driving it for about a week since fixing it. I changed the serpentine belt tensioner bearing assembly and the attached damper(it was squeeling and off angle previously). I'm still getting about 1.3 bar oil pressure at warm idle, 3 bar cold and at least 3 bar at higher RPM. Can I rule out a rod bearing just based on good oil pressure? Just don't want to spend another $300 on lifters if it needs rebuilt.
Thanks,
Ashley

W124 E300D · #5 10-29-2010, 05:01 PM

1/ Drain 2 litres of engine lube oil through the dipstick.

2/ Add 2 litres of Dextron II ATF to the engine lube oil.

3/ Drive it at least 250 "up to temperature" miles before changing the (engine lube) Oil and Filter.... MAKE SURE YOU CHANGE THE FILTER, strongly suggest a Mann filter.

The ATF is high in detergents, it will de-gunk your engine, and clean out clogged lifters.

When you do a fuel filter change, prime the new filter by also filling it with ATF, it will purge and clean the injectors.

scottmcphee · #6 10-29-2010, 05:57 PM

Why the "through the dipstick" trick?

There's a perfectly good drain bolt on the bottom of the pan.

ajnorris · #7 10-29-2010, 06:40 PM

Thanks for the advice. I'll try the trans fluid trick and see if that does the job. Is there a way to tell which lifter is the bad one by taking off the valve cover if it still makes noise? I was planning on checking the timing chain soon and figured while I was in there.....
Also is the white smoke in the morning and wet prechamber anything to be concerned about? I did verify all the glow plugs are working ( they all glowed red when I hit the key with the injectors out).
Thanks,
Ashley

W124 E300D · #8 10-29-2010, 07:05 PM

Quote:

Originally Posted by scottmcphee

Why the "through the dipstick" trick?

There's a perfectly good drain bolt on the bottom of the pan.

how do you meter out 2 litres of oil that way?

W124 E300D · #9 10-29-2010, 07:08 PM

Quote:

Originally Posted by ajnorris

Thanks for the advice. I'll try the trans fluid trick and see if that does the job. Is there a way to tell which lifter is the bad one by taking off the valve cover if it still makes noise? I was planning on checking the timing chain soon and figured while I was in there.....
Also is the white smoke in the morning and wet prechamber anything to be concerned about? I did verify all the glow plugs are working ( they all glowed red when I hit the key with the injectors out).
Thanks,
Ashley

yes, you can tell by hand, squeezing them down.

eliminate one symptom at a time gunga din, it is the only way.....

IF you still have a problem afterwards, pull all the injectors and get them serviced, while they are out, make a 50/50 volume mixture of acetone and ATF and flood the lower compression cylinder with it and let it sit a few days, crank it (by HAND, not starter) out before refitting injectors, check dipstick, then start.

50/50 acetone/atf is marvel mystery oil on steroids, a fraction of the price too.

300D85 · #10 10-29-2010, 10:37 PM

Quote:

Originally Posted by ajnorris

I'm still getting about 1.3 bar oil pressure at warm idle, 3 bar cold and at least 3 bar at higher RPM. Can I rule out a rod bearing just based on good oil pressure?

no

layback40 · #11 10-29-2010, 10:47 PM

"50/50 acetone/atf is marvel mystery oil on steroids, a fraction of the price too."

This is so true.

Dont get caught "borrowing" your better 1/2's nail polish remover (acetone). You are likely to find out how flammable it is & all the steroids in the world wont help!!

The oily finger marks on the container are a dead give away !!

vstech · #12 10-29-2010, 11:47 PM

Quote:

Originally Posted by ajnorris

I changed the serpentine belt tensioner bearing assembly and the attached damper(it was squeeling and off angle previously).
Ashley

just a little more info here. exactly what part on the bearing assembly did you change? the pivot bearing, the Belt rolling bearing pulley, or both?
this part?

or this part?

or both?

ajnorris · #13 10-30-2010, 08:44 AM

Quote:

just a little more info here. exactly what part on the bearing assembly did you change? the pivot bearing, the Belt rolling bearing pulley, or both?
this part?

I replaced both while I was in there, the pivot bearing assembly which was the issue and the pulley/bearing and the damper too since I had it apart.

Quote:

IF you still have a problem afterwards, pull all the injectors and get them serviced, while they are out, make a 50/50 volume mixture of acetone and ATF and flood the lower compression cylinder with it and let it sit a few days, crank it (by HAND, not starter) out before refitting injectors, check dipstick, then start.

I'm sure the injectors themselves are not the issue since I pop tested them but the the injector pump and the delivery valves are another story, havent got a clue (no service history). 0-60 times are about 12 seconds but only because I need to adjust the ALDA, it really pick up once over 15mph.

Quote:

Dont get caught "borrowing" your better 1/2's nail polish remover (acetone). You are likely to find out how flammable it is & all the steroids in the world wont help!!

The oily finger marks on the container are a dead give away !!

No kidding still getting grief over using the turkey baster to get oil out of the coolant overflow on my m103

Is there a big difference in sound between a rod bearing at early stages and a lifter. I guess it does sound a little like my gassers lifters when running 20-50 on a cold morning for the first few seconds which suggests lifters

babymog · #14 10-30-2010, 11:28 AM

Could even be a wrist pin / piston scuffing, hard to tell from the sound sometimes. A compression test and/or oil analysis would be prudent.

vstech · #15 10-30-2010, 11:35 AM

ok. the obvious is over. lets' focus on possibilities.
oil is due. what oil is in there now, and how long has it been? age, and miles.
oil filter, the tube, have you put new o-rings on the shaft?
vacuum pump. which one is in the car? flat plate with crimps, or the plate with the allen bolts holding it on?