1993 240 NA Coolant Bypass O-Ring

I?ve just recently purchased a 93 240, and it?s been great besides the fact that I can?t get it to stop leaking coolant. It first sprung a leak from the coolant bypass line that goes from the water pump to the heater core and bolts up to the exhaust side of the block. I cut out the leaky section and replaced it with a rubber hose temporarily until the new part came in. That was holding fine, however it started to leak from where the line met the water pump, but by that time the new lime had arrived, so I put that in. However, that started leaking too from the same place, where it connects to the water pump. I tried to find an OEM o-ring, but i only found one part number and it was wayyy too big, so I used a universal o-ring that fit perfectly. This didn?t work however, as it is still leaking from the same spot. Anybody know what I need to do or what o-ring to buy to get it to stop leaking from here??

This is what you need.

https://www.tascaparts.com/oem-parts/volvo-sealing-ring-418411

hiperfauto said:

This is what you need.

https://www.tascaparts.com/oem-parts/volvo-sealing-ring-418411

Click to expand...

Thank you so much, ordered it and it should be in soon. should I use any water pump RTV with it as well or just the seal?

Some people like to use RTV on the seal but I prefer to use a little white lithium grease. It doesn't really need any additional sealer but it helps to lubricate it to ease installation.

Haven't tried it myself before, but I heard if you loosen the bolt on the block that holds the pipe it will make it easier to install the pipe into the water pump directly straight and avoid leaks. Maybe this would help as well?

hiperfauto said:

Some people like to use RTV on the seal but I prefer to use a little white lithium grease. It doesn't really need any additional sealer but it helps to lubricate it to ease installation.

Click to expand...

DavePolyakov said:

Haven't tried it myself before, but I heard if you loosen the bolt on the block that holds the pipe it will make it easier to install the pipe into the water pump directly straight and avoid leaks. Maybe this would help as well?

Click to expand...

Yes because you can move the pipe a bit backwards, but accessing the bolt is quite clumsy.

Fa182 said:

but accessing the bolt is quite clumsy.

Click to expand...

What do you mean "clumsy"? It's right there. Out in the open. Easy peasy!





Unless your engine is, you know..... still in the car.
Then the exhaust manifold and downpipes get "slightly" in the way.

Make certain that the hole / fitting on the water pump that the pipe end slides into is completely free of contaminants and smooth.

Use either some RTV or Vaseline on the O-ring to allow it to move smoothly without getting a bit twisted / askew during installation: verify that the O-ring is properly seated after installation.

I have dealt with leaks here with overbored aftermarket junk.

Hepu pump+non corroded pipe----no leak.


I have had to desperately smooge RTV to stop a leak. Lube it first and make sure the lip does't roll.