S3 water pump into a S2 XJ6

Hello all,
The universe delivered to me a free new-ish water pump for a S3 XJ6 from Rock Auto, in very nice condition.

Now, I have:

  • A S2 XJ6 engine and car that need a water pump.
  • The original S2 water pump with a crusty bearing
  • A water pump from a federal S2 (with the fitting for the carburetors cooling), with an almost acceptable bearing.
  • The newish S3 pump.

I am not really into keeping things 100% original and looking at the options from this point forward.

It seems that the most reasonable thing to do is to use the new-ish S3 pump. This comes with 3 actions needed:

1- Plug the conduit to the throttle body. Done. I simply replaced the connector with the plug from the original pump.
2- Figure out a solution to mate the smaller bypass connector to the larger hose at the top. I am thinking putting a rubber sleeve to increase the diameter. Or may be I can find a bigger connector, or fit a S3 hose. TBD.
3- Figure out the fan/clutch and fan: the S3 pump pulley has 4 bolts sticking out, I suppose for a fan clutch, while the S2 fan clutch has a big bolt in the middle. Any suggestion on the best way forward?

  • Fit S3 clutch and fan? What minefield would this lead me into re the fan shroud, radiator etc…
  • Swap the pulleys (I read that pulling them out and pressing them in is not a fun job without heavy duty tools…).

Google Photos

Top: The S3 pump
Middle: Federal one with connector for the carbs
Bottom: Original with crusty bearing

Thank you!

Or how about if I just do away with the fan clutch and just fit the fan to the pulley?

Loud! Bad!

The S1 has a four bolt clutch. The single bolt version has been used on some S3s too I think. I can measure the bolt hole distance of my S1 clutch when I‘m with the S1 again. You can make out the bolts on the pulley…

So a S3 clutch and a S1 fan could work, is what I‘m thinking.
When you press out anything why not replace the bearing in the original and sell the other.

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Yes, the initial idea was to simply replace the bearing on the original one…

I was just hoping there was an easier way with the new S3 pump…

Or may be use the new S3 pump as is and go with electirc fans!!

I have such fantasies some time ago.


I am very tempted by this:


2 x 12" fans: https://www.ebay.com/i/293774764635?chn=ps&mkevt=1&mkcid=28

Carbs need heating, Eric, to prevent carb icing - coolant does that…:slight_smile:

However; depending on climate, carb heating may be superfluous - icing mostly happens in damp conditions around freezing point…

xj6 85 Sov Europe (UK/NZ)

Hi Eric,

When looking into this a while ago I found that there are no changes in fan shroud parts from S1 - 3.

I wanted a “short-nose” pump to allow more space for electric fan installation. I ended up buying a Series S3 pump, and I’ll be using the rubber sleeve method that you’re considering.

My S3 pump came with the clutch mounting studs loose, so you probably have the option of removing the studs from yours if you go electric. The bolt centres (clutch flange to pulley) seem to be the same for S1 and S3, so I think you can consider a Series1 fan and clutch or a Series 3 fan and clutch for your S3 pump.

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Eric, my 78 XJ6 when I bought it new, came with the 2 electric fans mounted
to the lower part of radiator, worked ever since then without any problem.

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I moved to HIF7 a long time ago :slight_smile:

Thank you folks.
After more reading and some sleeping, I am now leaning towards electric fans conversion. Different questions ahead… :slight_smile:

I also remembered that I have a S3 aluminum radiator in a box somewhere. May be things will come together… Oh wait doesn’t the S3 radiator have an extra pipe at the bottom??

Note to self: saw a Spal fan, 16" fitted to an aluminum radiator. Working well.