XJ6 water pumps

Hi,

can anyone tell me if there is a difference between the xj6 s1 and xj6 s3 water pump?
are they interchangeable?

I’m assuming you’re talking about 4.2’s, in that case the only important difference which will be a problem for the unmodified S1 cooling system is the massive size (diameter) of the S1 bypass hose nipple - the one that goes from header tank to water pump. S3 water pump has a much smaller bypass hose diameter.

Other than that they’re the same. I have a S3 water pump on my triple SU equipped S1 but I also use a S3 cooling system without the S1 header tank.

~Mike

You can use a section of intermediate sized hose as a bushing on the S3 bypass nipple to bring it up to the S1 bypass hose size.

Cheers thanks for the reply , yes 4.2

Thanks for the reply

Bear in mind that Ser III XJ6 pumps come in two flavors. Early, with the pulley/hub designed to accept the single bolt fan clutch. Late, with the pulley/hub designed to take the 4-bolt fan clutch.

I suspect, but cannot verify, that the hubs can be swapped, as I think that shaft diameter is the same.

Cheers
DD

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