Hello everyone, I have a '98 e300 with a belt squeak. I've used a stethoscope to determine conclusively that the squeak originates from the area of the crank pulley. I have replaced nearly everything else in the belt system in an attempt to eliminate the squeak, but nothing has helped.

The squeaking happens upon starting the engine and for the first ~5 mins of driving. After that, it goes away.

Stuff I have replaced so far, with no effect:
- belt
- tensioner arm
- tensioner arm bolt
- tensioner shock
- tensioner spring
- tensioner pulley
- alternator pulley

I got the part number off my crank pulley today, visible in the attached photo. It is 6060300403 but I'm wondering if maybe it's been superseded and there's a newer part number I should be using? The reason I ask is this p/n is original to the car, you can see the "04 98" in the photo, and also this p/n is hideously expensive. It's $800 or so at the usual online vendors.

Has anyone else had to replace this thing?

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1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

No newer part number.
6060300403 actually superceeds 6060300103.
Online MB dealer price $600 at MB of Clear Lake.

Used harmonic balancer at Pick-n-Pull, Oakland is $26.99 plus $0.99 core charge.
The harmonic balancer failed due to the crankshaft bolt backing out on my 78 300SD.
My independent mechanic put in a used unit.
No issues since the install.

You may want to check if the bolt securing the vibration damper to the crankshaft has the proper torque.
Also check that the six Allen head bolts on the harmonic balancer are tight.
I suspect that one or more of the six Allen head bolts is a bit loose or AWOL.
I don't know the torque values, but someone with a W210 FSM may be able to chime in with the values.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Torque specs are 300FT lbs IIRC with a 90 degree torque 2nd stage. So yeah, they're torqued on pretty good. Alec, I'd bet on your car the PO thought he could put the crank bolt on with an impact and that would be sufficient enough. That's why the bolt backed out.

Crank pulleys rarely go bad, so I'd get one from a yard that doesn't look like it had some major failure.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Bummer. Ok, thanks.

606 doesn't use these, has only the single center bolt:

http://www.w124performance.com/images/OM606_misc/OM606.962_engine/engine_01_front.jpg

I'm still not sure what would cause a belt squeak from this pulley. Searching the forums, it doesn't seem to be a common failure item on the 606 engine.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

How many miles.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Water pumps failing , it squeaks when its cold and then once getting warm its bearings have a bit more clearance and it quietens down.
I had this happen on my om606 and I checked tensioner , fitted a new shock and belt and even had alternator off to check clutch pulley to no avail.
The squeal is the belt slipping on the pumps pulley.

Its hard to fell for roughness / tight spots when turning pump due to weight of viscous fan assembly, but remove it and then turn pump when engines cold and you will feel the bad spots.
The noise gets less as engine gets warmer so you will find varying degrees of noise and it going away quicker dependant on temp, normally 3-4 minutes max.

Only 154k, but I have no history on the car (I just recently bought it)

Ooh that sounds *exactly* like my symptoms. Ok, I'm convinced, ordering a new water pump.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

This may sound a little weird, but it may just be a bad belt. I have tried this before and it works. It is easy to rule out a bad accessory. Spray WD40 on the left side of one of the pulleys (right before where the belt contacts the pulley). If the sound goes away, it is NOT one of the accessories, but a bad belt.

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All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html

It's Murkybenz for the win, thank you sir. Today replaced the water pump, thermostat, and upper & lower radiator hoses. Problem is solved!

It appears the old parts were original to the car, with date stamps of 1998.





Photo of "stripped" engine with the old stuff removed:



The radiator has been replaced with a Nissens brand one some time prior to my ownership. Do you think the PO used the proper coolant? Of course not.



Not shown, but there was a lot of shiny metal flakes in the old coolant. Bits of failed water pump bearing I guess. I performed three separate fill-drive-drain with only distilled water, before it drained clean and clear and with no green stuff and no metal flakes. Then added 5qt of blue MB coolant, and filled to capacity with more distilled water.

All good now!

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

Come to think of it, I just had to replace the heater duovalve a couple months ago. Was getting the typical bad valve symptoms of hot from one vent but cold from another. That was not an inexpensive part, $300 from Pelican. With all the metal flakes found in the drained coolant yesterday, I wonder if those flakes caused the duo valve to fail? Damaged or clogged the internals of the valve? Seems plausible.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

Metal flakes may be the residual evidence of prior treatment with a radiator stop leak product.

Unfortunately, the heater core may still require replacement at some point.
For your sake I hope not.
It's doable as a DIY, but very tedious work and expensive if you hire a shop to do the work.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Edit: after researching these stop leak products, I think you're right. What I have can best be described as "glitter dust". These shiny bits are not magnetic; if this was broken bits of water pump bearing, I would expect it to be magnetic. The pieces are uniform in size, and they're so tiny, you cannot feel them between bare fingers. Internet says there's a stop-leak product out there made with powered aluminum, and this seems like it.

HC's are PITA on most cars, not sure why they don't design them for better serviceability. I'm curious what the motivation would be to replace it in my situation? It isn't leaking, and the heat is nice and strong so it's not clogged either. During my triple rounds of fill-drive-drain with distilled water, I had the cabin heat on high the entire time, so the heater core would be flushed clean as well.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

I used Heavy Duty Bar's Leak decades ago as a stop gap measure (no pun intended) on an old Ford with a leaky radiator.
IIRC it had pelletized aluminum flakes in an oily base.
I remember seeing the shiny metal flakes in the coolant drain pan when I replaced the radiator.
Your post reminded me of that incident.
I've seen other others use stop leak products that can remain suspended and actually look like flakes of glitter in the coolant.

Since your radiator had been replaced, and the PO used green coolant, I thought the metal might be residue from using stop leak products.
Stop leak products shouldn't cause any large metal flakes to shed from your coolant system.
The flakes could very well be from the old water pump bearing, or bits of the aluminum water pump housing.

I'm not suggesting you replace your heater core at all.
I merely tried to offer a helpful suggestion that if the PO had indeed used a stop leak product to fix a leaking radiator prior to replacing it, that the heater core may be in a degraded condition, where it may fail at a future time, and that l sincerely hope that is not the case because it is a tedious job no one looks forward to performing.

We've all probably seen crusty evidence of intermittent pinhole coolant leaks that have temporarily self-healed.
However, it is difficult to directly visually inspect a heater core.
I hope your heater core remains healthy and that it never needs replacing.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Ah ha, I'm with you now. Yes I found on some other forums where folks described a fine glitter in their coolant, and it was attributed to the same stop-leak product, so I think you're right about it.

I'm hoping the radiator was replaced due to a puncture from a minor collision, rather than from deterioration / neglect. The inner and outer grill look newish, and the front bumper was painted at some point as there's overspray on the rubber headlight surrounds. I can't find any evidence of unibody damage or repair from above or below the front end, so it must have been a pretty minor incident, rear-ending someone in rush hour or some such. So hopefully that means the heater core is still in good shape. I'll knock on the wood trim for luck.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!