Intermittent Coolant leak
Thread Starter
Member
Joined: Jun 2007
Posts: 119
Likes: 11
2010 GLK
Intermittent Coolant leak
I have read through the posts about coolant leaks into the transmission, broken nipples and head gaskets. My leak doesn't happen all the time, maybe once a month or once every couple of weeks. It is a 2002 C230K with 140k miles. The leak is coming from the front of the car (I have seen fluid in the cross member at the front and it would have to drip down into this area). Our mechanic put it under pressure for a few hours and no leaks. When it does leak it drops a 1/4 to 1/2 liter. When I check the tank I'm pretty certain it is at the same place where it was before it leaked but after driving the car again the level goes down. This would indicate it is not in the circuit that deals with the reservoir. I'm pretty certain it has nothing to do with the temp of the engine...the other day we moved the car about 20', came out the next morning and there was a puddle. I'm thinking it has to do with the pump and only happens when the shaft is in a certain position.
Any thoughts appreciated.
Any thoughts appreciated.
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Joined: Mar 2008
Posts: 3,714
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From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Could be your coolant pump shaft seal is failing. Crawling underneath, removing the cover & checking with a strong torch should find the leak. Keep stopping & starting or rotating the engine by hand till it happens.
Let us know how you go.
Let us know how you go.
Thread Starter
Member
Joined: Jun 2007
Posts: 119
Likes: 11
2010 GLK
I couldn't find a DIY on the board for this engine but it looks do-able: remove airbox, drain coolant, remove air box bracket, remove hoses and pulley then finally water pump. I'll grab some photo's along the way but I have never been able to figure out how to post pics (all I get is a link when I post pics).
Anything that I should think about replacing while I'm in the area? I was going to put new hoses on, the belt looks pretty new, I'll check the tensioner out to see if it's noisy. I was thinking of a pulley upgrade for the supercharger but I don't need the speed.
Anything that I should think about replacing while I'm in the area? I was going to put new hoses on, the belt looks pretty new, I'll check the tensioner out to see if it's noisy. I was thinking of a pulley upgrade for the supercharger but I don't need the speed.
Thread Starter
Member
Joined: Jun 2007
Posts: 119
Likes: 11
2010 GLK
Took it apart and it was the water pump. Leak seemed to be coming from a the shaft itself...there is a tube, hidden by the pulley. I think the leak was coming out that tube. Maybe it is diverted on purpose. Picked up the new pump ($221) and a new hose from the lower radiator fitting to the pump. It looked like it would be worth replacing ($38). I'm pleased at how easy it came apart (about an hr taking my time). I don't know if I saved much money but it was fun doing it. Thanks to Carsy and Glyn for your help!
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