Water pump o-ring leaking. Sealant?

[hornet_guy]

Hello,

I replaced the water pump o-ring 1 year ago and now is starting to leak again (just drops for now). Assuming the o-ring is relatively new, I am considering 2 options:
1 - Cleaning the area and reinstalling the o-ring adding a good amount of gasket sealant around.
2 - Using sealant alone without the o-ring.

I know it shouldn't leak with the o-ring only as it was designed like that, but this is my case, and I want to ensure this doesn't happen again.

What do you think? What would you do?

Thanks

https://i.imgur.com/E8P2DIu.png

[Tdibs]

I would want do it do it by the book, drain coolant, strip and clean completely, new o ring, torque correctly and let it do its job.

Are the bolts done up to spec? was there corrosion when you pulled it before?
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Previous : 09 Vanvan 125| 02' Sv650s || Current: 1999 Xj600n | 1992 DR650 RSE | 2005 Fazer 1000

[jeffyjeff]

Agree with Tdibs. All that sealant can guarantee is frustration and foul language from the person that repairs the leak next time around, and that could be you. Get a new OE o-ring, clean the mating surfaces and the o-ring groove, tighten the cover to specification in steps. Make sure the leak is not coming from the drain bolt; your leak might be solved with a new copper washer.
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History shows again and again how nature points out the folly of men - BOC

[jaffa90]

[hornet_guy]

Thank you for the answers.

[Pete.]

O-rings need no sealant. Causes of them not sealing are shrinkage, damage, uneven clamping and a poor sealing face.

Since you replaced it a year ago it won't be shrinkage. Unlikely to be damage too so that leaves uneven clamping and had sealing face.

Remove the cover and inspect the face. If it has any corrosion depsosits or surface damage you'll have to clean it up. A soft wire brush will do a good job on aluminium (but a hard one will score it).
If the face that the o-ring seals onto (and the groove it sits in is clean) then it might be that the cover is warped. This might be just one of those things or it could be that it's bee over-tightened or tightened up without being properly cleaned.

Put up a photo if you're not sure. Show the o-ring, the groove and the face it seals onto.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[hornet_guy]

[jaffa90]

I would check the old o-ring for marks after noting the position it came out. Also without any o-ring join the surfaces together by hand and check for rocking or distortion.

[Pete.]

[bikenut]

Post a picture to show o ring seating areas for possible corrosion/pitting etc.
Also post a picture of the o ring to show a fault, both sides.

4 bolts hold the cover on and compress the o ring, do any of those bolts bottom out before providing enough clamping force ?

Measure, and pictures, is cover warped etc...
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nuts about bikes

[Pete.]

Generally speaking o-ring sealed faced always touch. The o-ring groove is sized so that when the mating face is touching the top of the groove the o-ring is properly compressed, it's all in the spec for making o-ring grooves. Foreign matter in the gap (often aluminium oxide on bikes especially water pumps and more especially where the coolant has been replaces with just water) can hold the faces apart and cause the bolt lugs to bend, then the faces will nevr touch.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[MCN]

New O-ring was possibly nipped on assembly.

Maybe it's the water pump Mechanical Seal is leaking.
The water pump should have a tell-tale (weep) hole near it's lower area.
This allows coolant that leaks past the mechanical seal to drip out the pump housing rather than pass through into the oil side.

If it has a seal and the sealing areas are sound then no sealant is required.
Some compounds can harm the seal material too so that should be considered.
Seals can break up or set hard like concrete.

All that should be applied is a lubricant. Either clean engine oil or some mild soap.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[sickpup]

Out of interest, what coolant are you using?

[rpsmith79]

If it is on a Hornet as your username might suggest, is it definietly leaking from the o-ring, or is it coming from the weep hole?

If it is the weep hole, then its a new complete water pump you need
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Current Bike: Honda CG125 ES4 // Honda CB600FS Hornet // Triumph Street Triple R

[MCN]

OP hasn't posted back so either:

Sold bike.
Dieded.
Power Flounced.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.