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Since 1987.
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Discussion Starter #1
The ZS has been leaking huge amounts of coolant for the last couple of weeks. Over the course of a week or two I've had to top up almost 4 litres.

Initially the problem seemed to be the thermostat housing, which was definitely leaking from the usual weak spot. The car continued to lose coolant after I replaced that, though, and it's the water pump at fault.

I've included some pics in the hope someone might have 'seen it all before' and know the exact source of the leak (i.e. which part of the pump).

For a bit of background info: I replaced the timing belts during the summer and the water pump was replaced at the same time (bought on ebay). However, one of the bolts did shear off and, as you can see in the pics, this was solved by me just drilling it out and using a piece of studding with a nut and washer on each end to provide the clamping pressure. This still seems secure, though, so even though it's an obvious possible cause, I'm not entirely convinced from the evidence in the pics (there seems to be more 'runs' from the top-right bolt).

Any thoughts?

Cheers!
 

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There is a rotating seal that keeps the coolant away from the water pump bearing, otherwise the hot coolant would flush the grease out of the bearing and it would fail . . . anyway, the hole at the top in your first picture is what looks like a weep hole. The type of seal usually used in water pumps can usually leak a little (weep) so a hole is put in to relieve the pressure and let the fluid escape, it looks like you have been losing fluid from the weep hole. If you are losing a lot from there it may well be that the seal has partially failed . . . if it has then it's time for a new water pump.
 

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Doesn't matter which part of the pump because any pump leak = a new pump.
My thoughts exactly.

I did wonder if the weep hole was in the correct place, shouldn't it be at the bottom?
 

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I replaced the timing belts during the summer and the water pump was replaced at the same time (bought on ebay).
Your the second person I've seen say exactly that, the other pump was supposed to be a genuine MGR part bought on ebay and was fitted by Gas-Axe so we can assume it was a pump fault.
 

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Yes - I'd be interested as to the origin of the replacement pump; the one that gave me trouble came in a plain brown box. Can't recall the sellers name now but it was sourced via ebay.

The problem with that pump was the main seal between the pump and the engine block wasn't "thick" enough so a decent seal was impossible to obtain.

A genuine MGR pump and all was well......after considerable effort tearing the engine down again!
 

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Since 1987.
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Discussion Starter #8
Cheers guys!

I think the seller was Teeside Landrover Specialists LTD (or something like that; we checked last night but I've forgotten the exact name already).

I knew I would have to replace the pump but if the diagnosis on here had been something to do with my DIY fix on the sheared bolt, I would have had to somehow get that drilled and a helicoil put in or something, too. However, it does seem very secure, so surprisingly I think it's ok (when I realised the pump was leaking, I got myself pretty convinced it was that bolt, so that's a relief, at least).

Getting hold of a new pump with all this snow should be interesting. :) I still have the old pump so I might even have to re-use that one for now and do the job again later on. The silver lining... I'll be a timing belt pro after all this. lol! :)
 

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My thoughts exactly.

I did wonder if the weep hole was in the correct place, shouldn't it be at the bottom?
It shouldn't really matter, it is on the bearing/dry side of the seal and is there to relieve pressure and fluid from any slight leak across the seal. If for example the weep hole was not drilled fully and was blocked then even a small leak across the seal would mean coolant at pressure at the bearing, this would eventually lead to a bearing collapse.
 

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Yep....thats where our dodgy pump came from I think...........

Nothing wrong with your bolt repair. Just fit an OEM pump from a trusted source and you'll be fine.

Compare the o ring body seals and you'll see where you problem lies.
 

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My thoughts exactly.

I did wonder if the weep hole was in the correct place, shouldn't it be at the bottom?
I thought that when I fitted a new pump to mine a few weeks back. Pretty much all the water pumps I have fitted have the drain hole at the lowest point; with it at the top the entire bearing housing has to fill with coolant before it starts leaking out.
 

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Since 1987.
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Discussion Starter #12
Yep....thats where our dodgy pump came from I think...........

Nothing wrong with your bolt repair. Just fit an OEM pump from a trusted source and you'll be fine.

Compare the o ring body seals and you'll see where you problem lies.
It's flush with (or even lower than) the level of the flange surface on the pump... useless!!! How was it ever supposed to seal anything when you can run your finger over the flange and not even feel the o-ring??

One seller to stay clear of, I think!
 

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It's flush with (or even lower than) the level of the flange surface on the pump... useless!!! How was it ever supposed to seal anything when you can run your finger over the flange and not even feel the o-ring??

One seller to stay clear of, I think!
If the water pump is OK and it's just an incorrect O ring then you can get the original O ring from MG/Xpart dealers, part no. is PET100760

http://www.rimmerbros.co.uk/Item--i-PET100760

of course if the O ring groove is too deep you are stuffed.
 

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Since 1987.
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Discussion Starter #14
If the water pump is OK and it's just an incorrect O ring then you can get the original O ring from MG/Xpart dealers, part no. is PET100760

http://www.rimmerbros.co.uk/Item--i-PET100760

of course if the O ring groove is too deep you are stuffed.
Yeah, I was considering that one, too.

I ordered one of those in advance of doing the job (thinking it was the bolt that needed sorting and the pump might need to come off) but I'm a bit wary of this pump now. Aside from the dodgy looking o-ring, there's a noise from either the bearing or the seal when I rotate the pulley by hand. I think it's the seal making the noise, but, not really understanding how the rotating seal looks/works, I can't say for sure. All I know is, my old pump doesn't make a noise when I rotate the pulley...
 

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I think it's the seal making the noise, but, not really understanding how the rotating seal looks/works, I can't say for sure. All I know is, my old pump doesn't make a noise when I rotate the pulley...
You don't want the bearing failing especially as the back of the main timing belt runs on it.

I know how these seals work but it's a little hard to explain . . . . the main sealing surfaces are seal to casting, seal to bearing shaft and then the rotating seal . . . it's made up of 2 discs usually one of carbon and one of ceramic. This might help if you are interested . . .

http://www.nbseal.com/automotive-pump-seals/auto-pump-seal-tpsb2d.html

I worked for a company in Birmingham for 6 years that make oil and water pumps for truck engines, so I know a little.
 

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Given the large amount of work to access this component I would only take the route of complete unit replacement with an OEM part.
 

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How have you got on Tommy?
 
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