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ML 350 CDI
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Discussion Starter #1 (Edited)
Started the engine this morning to a rattling noise and quickly shut it off. Either a cam chain (know all about those) or the oil pump chain, if they kept the design from the old sixes.
Thankfully no holes in the block, so it's a chain thing.... Hoping not cams otherwise bent valve city here I come........
What's annoying is that we're only at 47,000 miles......

So I know what I'm looking for, does anyone have an engine rebuild manual? Save me finding ut where everything is the hard way? Just need the front of the engine, specifically oil pump.
 

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Discussion Starter #3
Thankyou, sir!

Tell me, is it accessible just via removal of the front sump housing, without needing to remove timing case and main sump housing?
 

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02 ML320 06 ML500
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Thankyou, sir!

Tell me, is it accessible just via removal of the front sump housing, without needing to remove timing case and main sump housing?
How can you be so sure it is the pump or or the chain/or oil pressure? Remove the filter and clean the housing and replace and start it up. You will know if it has oil pressure by looking inside the filter housing.
 

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Discussion Starter #5
Man, I am not going to start it again without checking what's thrown. I've had two cars strip their oil pump drives (one Mitsubishi, one 3litre Benz, both due to PO's leaving sludge for me), so assuming the almighty racket is caused by no oil.
It's either that or cam chain, in which case it's surgery anyways. It's not any other engine component as it ran fine up to a start up the following day.
Just wanted to get all the info before pulling bits off.
 

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Discussion Starter #6
OK!

Lower sump removed, oil pump chain functioning as it should, cam chain still rotating and no metal. Little bit of sludge.

Remove easiest rocker cover and it's dry in there. Rotate engine on starter with ignition fuse removed and all is as it should be, with no noises.
But there's stuff all oil in the top of the engine.

SO looks like oil pump has drained back and failed to prime on start up. Which is odd, given it's virtually sumberged in the stuff..... So will remove pump and inspect and see what's next. I can only be thankful the cam chain is OK!!!!!!
 

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There is non return valve between oil pump and block. Most likely problem with pressure buildup at startup. Part number 611 180 01 15. (47)


.
 

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Discussion Starter #8
I wonder if that's a common issue? It would be most odd for the pump itself to have 'worn out' in 49,000 miles?

I'm off on a motorcycle trip for 2 weeks, so will dig it out of the engine and inspect upon my return. Thanks heaps for the NR valve part number too!
 

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Discussion Starter #9
Local dealer has no oil pumps in stock. So that's not a common issue.

However they have SEVENTEEN of the non-return valves in stock.

Tells you something, eh?
 

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Aussie, how did you resolve your problem? Was it the oil pump or the pump return valve? Lifters? I think I have same problem. Give us some details please. Thanks.
 
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