ML 270 cdi water pump test
Thread Starter
Junior Member
Joined: Sep 2014
Posts: 20
Likes: 0
From: Lake Taupo NZ
2000 ML 270cdi
ML 270 cdi water pump test
Hi All,
I overheated my 2000 270 cdi ML due to lack of water on Christmas day 50kms from home ..slowly added water and heard cracking sounds from water pump area and then a dripping leak from same area as more water added.
I have removed waterpump which visually seems ok impeller like new and spins OK with no noise ...no bearing wear movement ...had a thought that maybe the bearing will leak once I replace gasket ...
How do I bench test bearing seal ...?
Don't want to re-assemble the whole front of ML and find bearing leaks...and need to replace whole water pump...Cheers
I overheated my 2000 270 cdi ML due to lack of water on Christmas day 50kms from home ..slowly added water and heard cracking sounds from water pump area and then a dripping leak from same area as more water added.
I have removed waterpump which visually seems ok impeller like new and spins OK with no noise ...no bearing wear movement ...had a thought that maybe the bearing will leak once I replace gasket ...
How do I bench test bearing seal ...?
Don't want to re-assemble the whole front of ML and find bearing leaks...and need to replace whole water pump...Cheers
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
Likes: 56
From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
If it was leaking before dismantling then in my opinion ,there is every chance that it will leak again on assembly.
I have not seen your water pump but is it possible to "dam" a little water & leave it overnight to check ?. Then again it may only leak under pressure & when operating.
How did the coolant level become low? Any leaks ?.
I have not seen your water pump but is it possible to "dam" a little water & leave it overnight to check ?. Then again it may only leak under pressure & when operating.
How did the coolant level become low? Any leaks ?.
Thread Starter
Junior Member
Joined: Sep 2014
Posts: 20
Likes: 0
From: Lake Taupo NZ
2000 ML 270cdi
Thanks Carsy, I was loosing 500mls over 2/3 days but no obvious wet spot or drips on floor ...but under heavy load temp would increase then return to normal after less acceleration ...returning from 300km trip to coast temp went up but did not return to normal so stopped left it for 30mins and added 3 litres water from cow trough ..hence cracking sound from water pump with bigger water now leaking from behind main pully ..suspecting a destroyed pump as happened 3 years and 100,000K ago. But pump looks perfect slight water staining on lower bearing case area so may have leaked earlier......given visual condition looking OK hence thought maybe just gasket was leaking ...new pump in NZ $500 but 43.00 pounds ex UK.=$80NZ...but time delay in delivery over holidays... was hoping to test bearing and just install new gasket..
Thread Starter
Junior Member
Joined: Sep 2014
Posts: 20
Likes: 0
From: Lake Taupo NZ
2000 ML 270cdi
Thanks for your suggestion and poured water in up-turned pump and Yes bearing leaked, so no seal ...bugger new water pump needed ...Thanks for your help much appreciated.
MBWorld Fanatic!
Joined: Jan 2016
Posts: 2,748
Likes: 880
From: In the Shadow of the Tetons
2013 ML350 Bluetec
Torque values can be had with a subscription to Alldata.* I'd be more concerned about the loss of coolant without any appearing on your floor though. Half a liter over 2 or 3 days is a lot of coolant to just disappear. What does your exhaust look like when you start up? When the engine is warm? Any coolant in your engine oil? Any buildup of cooked coolant on your glow plug tips? Is the cooling system still pressurized when the engine is cold? I'm wondering how your head gaskets are.
*END2016 will save you $4 on a year's subscription, making it $12.95. I have no interest in the company other than a subscription for each of my cars and trucks, and it has saved me in a pinch more than a few times.
*END2016 will save you $4 on a year's subscription, making it $12.95. I have no interest in the company other than a subscription for each of my cars and trucks, and it has saved me in a pinch more than a few times.
Last edited by rapidoxidation; Dec 29, 2016 at 11:05 AM.
