Water pump leak

Chaud

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#1
Make
Mercedes
Model
C230
Year
1997
Miles
192190
Engine
111.974 4 cylinder
Just installed a new water pump and noticed it is leaking near a 10mm bolt. I don't know if water coming through threads to the top or between gasket and mating surface. I was wondering if it is ok if I use thread sealant on the bolt or wrap a teflon tape to stop thread leak. If this did not help then have to take out the pump and redo all over which I hate to do if there is a way out. I will appreciate you thoughts and help on this.
 

grcauto

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#2
If it were leaking through the threads I would say OK but I doubt that the thread hole were deep enough to reach the water jacket.
 
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#3
If you want to find out if the threaded hole needs have sealed threads, simply remove it to find out if coolant flows out of bolt hole.
 

nickb2

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#4
simply remove it to find out if coolant flows out of bolt hole.


Ignore all the BS and focus on the steak.



Yup, sums up pretty much what I think, that or the threads stripped and gasket failed.
 

nickb2

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#5
Last ditch, JB weld a bit on a new 10mm, if it still leaks, JB weld is going to have to be broken and may cause more greif than you want.

A bolt like that should be no more than 30lbs/ft tight. If it still turns after that approx torque, with out sealing, probably stripped threads or initial bad installation of gasket/ o-ring or pump cracked in or around that particular bolt.

Scratch oring, it is a gasket, just checked.

And my aprrox torque 30ft/lbs is nowhere near real specs , it's 25N/m for M8 bolts, and 10N/m for M6 for pump to crankcase. Confirms also what GRC auto said, none go even close to cooling jacket. This is a cassette style pump.
 
Last edited:

nickb2

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#6
BTW, for those who don't know, it is not because a 10mm socket fits a 6mm bolt that it is a 10mm bolt. Quite the contrary. To drive a 14mm socket should apply to a 10mm diameter or so of said bolt.

So approx torque I gave should apply to 10mm or 3/8 bolts or studs.
 

nickb2

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#11
Mind you, I strip bolts very not often anymore, cuz I am long into this trade, but when I was young or in experienced, JB weld was go to.

Ain't never seen other that may save the day in last ditch. I know ppl don't have time to watch my videos I find on boob tube, but thoe who know, JB is "the BEST last ditch" thing.
 

nickb2

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#13
So, last useless reply till I retire, I once save a subaru crank case with a chronic leaking WP. No space to drill and tap without making huge space for tapping and machining. I JB welded it. Did another Timing belt on it 100k km's later, pump was fine.

By then the engine was on last legs. No coolant leaks, but huge amounts of oil consumption from inside of engine.

Just goes to show. You don't use bathtub silicone to seal an automotive engine.
 
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#14
Just my personal opinion if I just did it and it was nice outside I'd probably pull it back off and check for what I missed. Its leaking for a reason. However... id take the bolt out and put in rtv gasket maker in there and put the bolt back in. Your gonna play hell when you have to change it out again.
 

Chaud

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#15
Thank you all for your good suggestions. I tried some except JB weld. I even swapped the bolts and put teflon tape on the threads. But still I could see a drop or two of antifreeze falling on the ground every 5 seconds or so. Did visual from the front of the car no sign of leak. Then I looked from the driver side and I found the problem. Top hose going to thermostat housing at the clamp was dripping. Once I tightened the clamp, all the leak disappeared. It shows sometimes the problem is staring at your face as grcauto once said but we cannot see it. I thank you all again.
Chaud