[Sean's Jaguar XJS Tech Pages]
The Water Pump: Coolant Crossover Pipe Modification

Last modified 2005 APR 07 04:40:13 GMT

As anyone who has dealt with the V-12 coolant crossover pipe can tell you, it is a bear to install. With this in mind, I elected to make an easy modification to mine which greatly simplifies the reinstallation.

No mention of this would be complete without also noting that if you need a replacement (because yours is corroded beyond reconditioning perhaps), that there's an outfit in Sydney called Cathouse Spares who can provide you with a STAINLESS STEEL replacement pipe (and header tank as well). If you're planning on tackling this, now might be a good time to order up the replacement components before disassembling everything. There's also a writeup in Kirby's book.

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After removal of the coolant crossover pipe, I beadblasted the entire thing, then repainted it.

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As I had purchased about a foot of the hose for either side of the coolant crossover pipe (where it meets up to either head), I had an available length to use for the crossover mod. By cutting the crossover pipe near the water pump fitting, the installation is GREATLY simplified. By using good hose clamps, the crossover pipe doesn't lose much rigidity. If you wanted to be really retentive, you might even consider a metal sleeve, with an ID to match the OD of the crossover. You could slip that over the crossover, then slip the heater hose over that and clamp it. Another thing to do (if you have the equipment, or the time to take the crossover to the appropriate shop) is to get the fitting threaded on the outside. By doing this, you could then thread a coupling over the two pipes (after treating the threads with an appropriate sealer). The hose seems to work just fine.

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Overview of the coolant crossover modification with the connecting hose clamped on. This was BEFORE I realized that one of the clamps would interfere with the travel of the (not yet reinstalled) belt over the AC clutch.

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As mentioned above, OOPS. This wasn't fatal - I just had to rotate the clamps to screw from the backside of the crossover pipe (between it and the block). However, as I show below, making the cut just a little closer to the vertical pipe to the water pump would take care of this clearance issue.

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See the totally vertical mark? That is where I cut mine. However, about an inch to the right of that, there's a mark here on the top of the pipe. This would be a much better place to cut the pipe, as you'd then be able to clamp it entirely away from the vertical of the A/C clutch belt. When I eventually revisit the crossover to replace it with a stainless steel version, I'll cut it there.


Sean B. Straw
Post Box 751224
Petaluma, CA 94975-1224 USA

EMail to: Sean.Straw+Jaguar@mail.professional.org

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