Coolant Leak Puzzle

ian640

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Hi,

In the middle of last year the water pump was recently replaced on my XCh (as a preventative measure, no leaks beforehand) and at the same time the radiator was removed to be cleaned.

A couple of thousand miles or so of TET later, there is what I'm 99.9% sure is coolant leaking from the hole between the water pump seals, implying that the coolant side seal has failed. The expansion tank is almost empty of coolant. I forget the brand of coolant used to refill but it's pink and I recall magnesium friendly.

Whilst riding the TET there was no sign of overheating.

Given the pump shaft, impeller and seals were new and as far as I know OEM, I'm baffled as to what could be the cause of the failure. Could the leak be caused by a pressure build up itself caused by another component failure? Any ideas welcome.

I'm hardly relishing the thought of removing the swinging arm, frame component et al. to fit a new pump and seals, especially if it has to be done again in the new future if the root cause is not established.

Thank you,

Ian.
 
Hi ian

Two things spring to mind that could have caused this issue , firstly did you assemble the seals in the correct orientation - i.e with the open lipped ends towards the fluids ?

Secondly did you follow the BMW workshop instructions and fill the void between the seals with Molycote 111 Lubricant ?

I've replaced a number of shafts/seals and thus far not had any issues



Also the BMW recommended coolant is not pink it is the blue coloured variant - I always use the OEM coolant :

https://www.ebay.co.uk/itm/Genuine-...910072&hash=item28a678a9e9:g:jckAAOSwTSdfXzhg

Hope the above helps
 
Hi John,

Thank you, it is helpful.

I didn't actually do the task, but I've been assured that the specified instructions were followed.

Nonetheless mistakes happen, so I'll be replacing the shaft and seals myself in the next couple of weeks.

I will use BMW coolant and the specified grease.

Hopefully all will be revealed.

Kind regards,

Ian.
 
With the shaft having just been replaced it should not need replacing again so you will be able to just buy the two seals . BMW do not offer the seals on their own but only as a kit with a shaft so quite expensive , you can however buy the seals from Simply Bearings or Motobins
 
If it’s pink and magnesium friendly then it’s most likely a G12 coolant. Most good brands will offer a G12 coolant you won’t need the B!S stuff it’s used in a lot of cars too and they usually have G12 Only stamped on the reservoir cap as you shouldn’t really mix it with regular coolant. My Honda requires G12 and I use Putoline Ultracool. Have a look in your handbook :thumb
 
If it’s pink and magnesium friendly then it’s most likely a G12 coolant. Most good brands will offer a G12 coolant you won’t need the B!S stuff it’s used in a lot of cars too and they usually have G12 Only stamped on the reservoir cap as you shouldn’t really mix it with regular coolant. My Honda requires G12 and I use Putoline Ultracool. Have a look in your handbook :thumb

As per my earlier post the recommended coolant for the G650X range is BMW part number 83 51 2 445 463 mixed in a ratio of 1:1





I have it on good authority that the BMW Lifetime Coolant 87 I posted above in the earlier link is also suitable and is in fact described the same as the Motorrad coolant as "Anti-freeze and anti-corrosive for radiators, free from nitrile"

I would always flush the system first when I get a bike and then change the coolant as you do not know what the previous owner may have used
 
Thanks all, I will use the BMW coolant.

Tip about the seals noted :thumb
 
Very sorry Nicholson I didn’t see your original eBay link :blush

It isn’t a G12 coolant and therefore won’t be pink exactly as you said. It’s just an ordinary modern nitrite free OAT coolant (Organic Acid Technology) much better suited to modern engines with an alloy / magnesium component than the older nitrided coolants as it has better anti corrosive properties.

There would be no problem “upgrading” to a G12 coolant if you wanted for even better anti corrosive qualities and also a longer service life so long as you flush first. BMW won’t make that coolant , somebody else does for them and then it’s put in a BMW labelled bottle, it’s not special ........ just saying :thumb
 


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