Water pump o-ring or flat gasket?
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Mp3 500 2010
Joined: 07 Jul 2020
Posts: 5

Wed Jul 08, 2020 12:41 pm quote
So I just replaced my water pump o-ring after cleaning all surfaces, but as soon as I added coolant it was leaking all around the water pump cover, I called my dealer and made sure my o-ring was right and it was, Iíve been keeping the screws tight too. So my dealer recommended a small amount of sealant, but before I do that, has anyone tried a flat gasket? My dealer has one that fits my bike (but they said the part catalog says I should use an o-ring if thatís how I started) Iím hoping someone has any ideas? (In the picture you can see both the gasket and the o-ring)


Gilera Fuoco 500ie
Joined: 11 Oct 2009
Posts: 4184
Location: Netherlands Olst
Wed Jul 08, 2020 1:11 pm quote
use the ring or the gasket not both the gasket is a replacement for the o-ring
Mp3 500 2010
Joined: 07 Jul 2020
Posts: 5

Wed Jul 08, 2020 1:17 pm quote
Maksor wrote:
use the ring or the gasket not both the gasket is a replacement for the o-ring
Oh no way! So even though my cover was using an o-ring your saying that if I use the gasket it will still work? Or work better I suppose, that would be great
50cc Beo, BigBeo
Joined: 30 May 2015
Posts: 234
Location: Chelyabinsk, Russia
Wed Jul 08, 2020 8:22 pm quote
Here's what is going on.

There are three versions of pump cover.
AP8570031 was a plastic one. Was used with round gasket (kinda o-ring, but pump cover shaped numbered AP8560073). It was used at least at my Big Beo (Scarabeo 500GT 2003)

875315 was used on newer engines. I don't know if it is the same as AP8570031, but looks similar. It was used either with gasket 875316 OR with gasket 879210. And I don't know if they are same, or one is flat and another is round.

Now there's a current version of pump, B019381. It is a replacement for aforementioned and is made of metal and used with flat black gasket made of foil, 879210.

The replacement is exactly because the plastic one with round gasket is very common to leak even with new gasket. And I don't know if it can be used with flat gasket and if holds coolant in such case. Anyway when I've done a pump overhaul, I had to use some sealant, and later I bought a metal pump cover to replace the plastic one if it leaks again.
2009 MP3 400
Joined: 11 Jun 2007
Posts: 212
Location: Sayre, PA
Thu Jul 09, 2020 2:11 am quote
Makes me feel better that I upgraded to a metal cover when I was first getting mine up to snuff.

Cut a flat gasket to fit since it didn't come with one. Haven't had any leaks since.


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