Replacing Water Pump, what about 105196?

Is yours leaking between the block and water pump housing?

 

Fyi, the O ring needs to be EPDM, not Buna for this application. The normal suppliers would have the correct O ring, the OEM size is apparently ID 34.59mm x 4.7625 thickness. These would be the closest imperial size O rings..https://www.amazon.ca/gp/product/B001D8BZOS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I don't think there would be a simple way to replace this without the same disassembling one would do to remove and replace the water pump.

The O ring goes in a circular groove in the water pump/thermostat housing and seals this water passage against the engine block. When you try to take off just the water pump, there are four nuts on studs that hold the water pump to the water pump housing, but there are also four long bolts that also hold both the water pump and the water pump housing in place against the engine block. Often the water pump and housing are stuck together, so you end up removing the whole assembly, and separating them on your workbench. You dont want to pry and damage the sealing surfaces. You would be accessing the pump nuts and bolts through the wheel well, although some would be accessible from the top of the car with the air filter out of the way.

To remove the pump housing (and water pump together) you to remove the two coolant hoses that go under the intake plennum that attach to the pump housing, and the other coolant hose you would easily access and see near the thermostat when the air filter cover is off. Like all rubber radiator hoses, they can also bond to the aluminum, and be stuck on pretty good if not removed recently (or are not silicon like I now use for this servicing reason). Access to the clamps that go under the plennum might vary depending on how the clamp is oriented, I find the access tight but doable a small quarter inch ratchet and socket for the clamp bolt. ie. no need to remove the plennum.

All in, the job is technically straightforward, but probably more involved and time consuming than you were hoping for. I just did all this while also doing a belt change, sorry, no pictures.

It is possible that O ring is leaking, especially if it has not been replaced while doing water pump changes, the O ring is under compression and will set and lose its seal over time. But it is also possible your water pump is leaking, at the two little weep holes just under the pully stem, this is a sign of a bearing/seal failure inside the pump. The thermostat housing can also leak, and the bleed screw in that housing as well could be weeping.

 

That is not the correct O Ring size. Some suppliers are selling those and many cracked water pump housings have been the result.
The correct O ring is 2.5mm section thickness, not nearly 5mm. It should just slightly stand proud of the casting surface when set in the groove.
Thats what happens when parts are bought from suppliers with little Ferrari knowledge.

The o ring never sets and loses its seal.

 

Once more without all the static, is yours leaking?

If in fact it is just the O ring it can be very easily replaced with very little disassembly.

I will add leaking from the O ring is very rare. Any fluids leaking on the top of the engine leak down the front behind the water pump right next to the casting where the O ring is and is often mistaken for a water pump leak.

 

You have incredible knowledge and experience, and I always appreciate your comments.

The Amazon link I provided is the correct O ring, 3/32 inch is about 2.6mm. I just did my water pump, and this O ring is Identical to that provided by a well regarded US supplier.

I put in the OEM metric size for further information from another old Fchat thread which was an incorrect thread. Error noted.

O rings do set and lose their spring. That's why eg. you don't use eg. Viton for this type of O ring application, Viton does not hold its spring under compression as well as other materials, regardless of other benefits.

If this fellow in fact has an O ring leak, by all means buy from a Fparts supplier. Or buy the pack and have lots of spares.

I am keen to hear how you could slip that O ring into that groove with the water pump housing still attached but presumably loosened and hoses loosened up. Possible. I followed your shift shaft seal replacement without oil pan removal so I know you have plenty of inventive ways to get things done efficiently.

 

Trying to replace the pump without removing the entire assembly is a waste of time. The difference in effort is 2 hose clamps.
With the 1-4 belt cover off if the 4 8mm bolts are out you can just tilt up the housing a little and replace the ring. I have done it. But if you have just replaced a pump there are a bunch of pitfalls. Id just undo the hose clamps for the big hoses on the back and remove the entire unit.

You profile has no information for what kind of car we are talking about here so you are really making it hard for people to help you. A lot of my answer is guess work because of it. That area to be filled out in your profile is not to invade your privacy. Its so we can help you.

 

I think the point @Rifledriver is making, is that your initial comment about sizing is not correct. The 105196 o-ring is 2.5mm thick and has an ID of 36mm.

 

Understood, thank you for confirming the correct metric size. The link I provided is for the correct imperial size equivalent.

Understood. I had noted incorrect metric sizes when I made the thread response in haste.

This is the old thread I was actually intending to refer to.
https://www.ferrarichat.com/forum/threads/water-pump-housing-o-ring-size.610701/

This notes the OEM size is 34,59 x 2,62 mm.

This equates exactly to the imperial size I noted in the link.

I hate to beat this dead O ring horse, and I know you are the most highly regarded US supplier. But the imperial size I note is exactly equal to that metric size in this old thread, which in turn is identical to a ring provided by another well regarded US Ferrari supplier. The old thread also notes the size is common in Europe, which is correct. I have installed the O ring noted, and it fits as one would expect.

I am happy to stand by your confirmation of the correct size, but thought it appropriate to revisit given the conflicting information.

 

This looks damaged already

 

Where?

 

O-ring has what looks like a nick in it to me. Also, looks to have scar marks on the body. Would these be casting marks? I don't know.

 

Left above from the bottom hole looks like damage. May be the light from the picture taking reflecting off some grease.

Scar marks on the pump body look harmless.

 

The water pump belt also has the tensioner, which actually has two small bearings in that pully. They are often not changed as frequently as eg. the cam belt bearings, but probably bear more tension and load. Some say they can be noisy when cold.

Easy to access and replace, you put the assembly in the oven, heat things and the press fit bearings almost drop out. There is a thread on this, a circlip in there, etc.

https://www.ferrarichat.com/forum/threads/water-pump-tensioner-bearing-s.262593/#post-139080510

https://www.ferrarichat.com/forum/threads/328-v-belt-tensioner-bearings.352372/