So after trying to figure out why my radiator kept draining and at first I thought it was the radiator cap (which was leaking but probably started due to other issues) I was on a ride down to north wales when again my engine warning light came out after i thought I had fixed the problem and I found the radiator completely empty and so was the expansion bottle.

after a lot of filling up and faffing about trying to find where the water was coming from finally now found out it is from the water pump housing on the underside where there is like a drain hole.

Ive had a quick look and found one thread on here about a similar issue and it mentioned its bikes way of stopping the oil mixing with the water and the seals are on the way out so leaks here rather than mixing the two together?

If that's true does anyone have a link to a how to replace guide?

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Plough on

The Down loadable workshop manual on this site, page 279, section 6-9.

I just replaced the rubber oil seal in mine. You'll need a small circlip plier to get into the seals. Have fun

It'll be the mechanical seal in the water pump that's failed if it's leaking through the drain hole, which is exactly as you say a tell-tale to let you know there's trouble and to prevent cross-contamination of oil and water from the two sides of the pump.

Have a read of this thread. It covers parts needed and the basic outline of what you need to do.

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Dazzer

ill have a look in work tomorrow as I have the CD work shop manual for my old XTR which should hopefully be the same

Pleiades

yea that was the thread I had read.

Well I will have a look at the work shop manual but the next question is why would it have failed? is it due to the water pump failing first, is it due to me doing something wrong when I changed the coolant some 2-3k miles before or is it just something that goes over time?

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Plough on

They just fail, simple as that. It's unlikely there's anything you've done, or rather not done. Running the cooling system with 100% water and no coolant can accelerate pump wear as part of a coolant's job is to lubricate the pump bearings, as can neglecting to change the coolant at regular intervals as it can become acidic, contain debris that is abrasive and the lubrication/corrosion inhibiting properties decay over time. Like any bearing and seal though, they do have a finite life and in your case, it's number was probably up.

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Pleiades

ill hopefully have a look into it later on this week after work/weekend and see what seals are damaged before ordering. fingered crossed its nothing else

Never really ever changed coolant on any of my bikes but its always been something ive wanted to do just never learned how to do it. This was I think the first time my tenere had it done so thats around 5-6years so was probably due it.

the usual I now know how to do it ill probably change bikes and not have a clue how to do it on the next one!!!

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Plough on

So the problems goes on. I got the waterpump out and took it to a Yamaha dealer and they confirm its was the mechanical water seal that has failed. So ordered a new one and it come in two parts. One is like the main housing made of metal and a spring (ill see about getting photos tomorrow) and the other is a small rubber seal. however when you look at the manual it shows these as one piece and there is no obvious way to make them one and to make it all seal to the impeller shaft.

has any one any photos of theres?

even after phoning my Yamaha dealer they hadn't a clue and even tried to get me to book it in through their service department to get one of their mechanics to look at it!!! hopefully if I turn up tomorrow they might be able to sort it!!

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Plough on

When you buy a mechanical seal from Yamaha, what you actually get is a 'seal kit'. This includes the rubber damper and its holder which sit inside the back of the impeller - which is I suspect what you are talking about? The oil seal (if you ordered one separately to the mechanical seal as well) would be an obvious single part.

It is not absolutely necessary to replace the damper and holder unless they are obviously worn. If you are going to do it, then you need to lever the olds ones out of the recess in the back of the impeller. (At this point, when you've got the old holder/damper out, how it all goes together.) Slide the new holder and rubber damper down the shaft and drift/press into the recess making sure they're flush. The two parts become one when they are pressed home. A good dousing in neat coolant makes everything slippery and much easier to get fit together.

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Pleiades

This includes the rubber damper and its holder which sit inside the back of the impeller - which is I suspect what you are talking about?

Yes that is what im talking about, i can see where the white plastic holder sits in the impeller head however there is no sign of the rubber damper/seal or where this would sit

ive got the old oil seal and bearing out ok so have a pile of parts and the only two are the mechanical seal and the rubber damper with holder that i cant figure out. i cant see what way the water seal is created between impeller shaft, rubber damper/seal and mechanical seal as none seem to fit size on size and therefore water would pass between the impeller shaft and mechanical seal as theres no rubber and just straight out the drain hole!!

i can understand where the rubber damper holder is but theres no sign of any rubber seal when i took mine apart (its probably been ripped to shreds over time?) but its how you get it all apart as there isnt really any gaps to get things out in the impeller with and what way the rubber sits as there is no signs of any rubbers. Im assuming the rubber faces back towards the mechanical seal.

Heres the bits of have of sorts. from left to right are rubber damper and holder, mechanical seal, impeller shaft and chog, oil seal, oil bearing



from what ive gathered is this the way they should be arranged (sorry cants take the chog off as i dont have circlip removers with me in work!!)
the mechanical seal will get pressed into the main pump housing, then the rubber damper and holder get placed into the impeller head the way below and they just put rubber face to the mechanical seal face and thats where the water seal forms?

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Plough on

Yes, that's the order it goes except that you have the damper and holder the wrong way round from what I can see - the rubber face goes into the recess in the back of the impeller. Obviously the mechanical seal assembly needs pressing into the pump body first, then fit the impeller (with it's damper installed).

However... Looking at the corrosion and corresponding abrasive surface on your impeller shaft, I very much doubt that the new mechanical seal is going to last that long! If it was my bike, and I'd got this far into the water pump, I'd be erring on the side of replacing the impeller. You don't want to have to be going through all this again in a hurry!

Corrosion like this I've only ever seen before on motors run on pure water, or with old coolant that has lost its corrosion-inhibiting properties. When did you last change the coolant?

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