2005 CDI Water Pump Failure - PeachParts Mercedes-Benz Forum

arcteryx · #1 12-10-2017, 09:48 PM

Yesterday the wife was driving back from Houston in the CDI when she said the coolant light came on. When she called to tell me, I told her to just keep an eye on it. When she got about 60 miles from home when she stopped at a gas station and checked the level as the gauge had climbed to slightly above halfway which was not normal. After some more discussion, we decided it was best if I go get her and the CDI with my trailer, which I am glad I did.

Today, I opened it up and saw the serpentine belt was off as well as the water pump pulley was angled. I poured some water in the reservoir and it came right out the bottom of the water pump. When I finally got the pump removed and inspected it, I was amazed at the damage done. I am guessing the bearings in the pulley went bad so it became skewed, causing the belt to slide off. Additionally, the propeller blades dug into the block. The pulley screeched as I turned it in my hand with the blades rubbing on the metal, like fingernails on a chalkboard.

Pics of the scratched block and bad pump are below. I have a new parts coming Tuesday.

Diseasel300 · #2 12-10-2017, 11:31 PM

Yikes, that's pretty catastrophic! Did it have any warnings at all, or did the bearings just let go all of a sudden?

arcteryx · #3 12-10-2017, 11:41 PM

Not really other than the coolant light. In hindsight, the few cold days we've had here in Texas and I used the heat, it was marginal at best. I should have determined the coolant was low but based on that but did not. In my defense, I have only had it for almost 3 months so still getting to know it.

ESchwab · #4 12-10-2017, 11:55 PM

Check your belt tensioner. I have a '98 e300. The alternator pulley on my car came apart, and I lost most of it when my car was just idling in heavy traffic. When I put things back together, I discovered that the tensioner pulley was bad, apparently a failed bearing. I think that problem caused the problem with the alternator pulley. Presumably, it could also cause problems with a water pump.

I'm just a DIY guy rather than a real mechanic. I just want to give you my experience so you can check to see if you have the same problem I had.

engatwork · #5 12-11-2017, 07:47 AM

What mileage was the original posters engine at when it happened? I've already replaced all these components on my 98 E300 by 200k just for preventive maintenance.

arcteryx · #6 12-11-2017, 08:11 AM

It has 104k miles

spark3542 · #7 12-12-2017, 02:40 PM

I had the water pump fail on two of my CDIs...one at about 150k, the other about 210k. "Coolant Low" message was the telltale indicator. I couldn't find a bad leak, or coolant in the oil, or white exhaust. It was a slow leak while driving, nothing even on the garage floor.

Neither of mine however, failed catastrophically like yours. I never lost the belt or gouged the block.

Zulfiqar · #8 12-12-2017, 02:48 PM

thats pretty bad. The diesel noise of the motor covers rough rumbling at idle, it must have been rumbling for a while.

With such kind of failure - flush the system till you get sick and tired of flushing - open all drains and rig up your garden hose to wash every metal shaving out.

I have seen such a fail take out the next 4 water pumps due to the metal in the coolant.

arcteryx · #9 12-12-2017, 03:29 PM

Where is the drain plug on the block?

engatwork · #10 12-12-2017, 05:27 PM

Typically about 1/2 down the side of the block, about 3 or 4 up from where oil pan bolts on, on the passenger side IIRC.

arcteryx · #11 12-12-2017, 05:43 PM

Quote:

Originally Posted by engatwork

Typically about 1/2 down the side of the block, about 3 or 4 up from where oil pan bolts on, on the passenger side IIRC.

thanks

torsionbar · #12 12-14-2017, 08:51 PM

The water pump failed on my om606 this past year. It gave an audible warning in the form of a loud annoying screech that varied with engine rpm. The screech only occurred on a cold engine, and went away after ~5 minutes of driving (i.e. as the engine warmed up). Failed water pump bearings. A new water pump cured the noise. The old failed pump was the original from 1998 according to the date code on it.

Diseasel300 · #13 12-14-2017, 09:52 PM

It's interesting how things progress. My SDL's had an intermittent very faint "cheep cheep cheep" sound at idle at random times for several months. Any time I've ever tried to locate it, it's always stopped before I can pin it down. Those are the types of troubleshooting jobs that really chap my ass...

Long story short, the noise was fairly loud today and was kind enough to keep going long enough for me to track it down to the water pump. Pulling the belt and giving it a spin by hand yields a "GRRRRRRRRRRRR" of ruined bearings. New pump now on order. The surprising part is that the bearings are still nice and tight, no slop, no leaks. Pretty sure it's the OEM pump too, so it doesn't really owe me anything.

DieselPaul · #14 12-15-2017, 01:24 PM

My E320CDI makes a chirp that you can only hear right as you shut the car off so the engine isn't making any running noises... sounds like I should check the water pump for play.

Thanks for the post.

JimFreeh · #15 12-16-2017, 10:40 AM

Quote:

Originally Posted by DieselPaul

My E320CDI makes a chirp that you can only hear right as you shut the car off so the engine isn't making any running noises... sounds like I should check the water pump for play.

Thanks for the post.

Paul,

My Dodge-Cummins has been doing that for 20 years......

It's caused by the belt slipping on the crank pulley.

When you shut off the engine, the compression stops the crank rotation quicker than the belt can stop turning.

Jim