I've got (at least) two leaks.

The first one may have been discussed here, but I can't find reference to it. There's this plastic tower thingy that accepts the thermostat (XK8) and on top has a large cap that opens using a hex key ... 8 mm, if I remember right. I've got a leak around that cap when the system is under pressure.

Has anyone dealt with this one? Can a new seal be put in the cap, or does everything have to come out and be replaced? (I can't detect any cracks in the plastic.)

I've also got seepage around the filler cap on the expansion tank. Are new seals a possibility here, or just go ahead and replace the cap?

Best supplier for these kinds of parts? Coventry West?

Any suggestions much appreciated.


(Some people believe that there is no malevolent force at work that makes these things show up in the dead of winter, but I am not so sure.)

 

Dennis, the cap on the thermostat housing can be purchased seperately, but you can also upgrade the complete thermostat housing with a aluminum housing. The replacement kit may or may not include a new thermostat.

The same applies for the expansion tank. You can purchase the cap seperately, but a new expansion tank comes with a new cap as well.

Shop around, I have seen the complete thermostat housing with thermostat for about $70, and the expansion tanks for about $140. Start with some of the sponsors on the site.. jagbits.com, coverntry west, sng barrett, etc..



If you have not replaced the expansion tank on your car, I suggest replacing it. It is a very easy job to do. Do a search, and you will find some good info. As to the thermostat housing, do a search as well.

Good luck!!

 

Hi Dennis, FYI we currently have the thermo housing kit on special offer..


www.sngbarratt.com/SpecialOfferDetails.aspx?id=066734d3-2da3-4ab8-9683-a5cce693df6d


Expansion tank also available and eligible for 10% jaguar forum discount.

 

Welsh Enterprises sells a good quality aluminum thermostat housing and includes a new thermostat.

 

Take the t housing cap to the hardware store and find a fat o-ring that fits inside the cap - should hold you till warmer weather (or forever). Even a flat washer could work.

 

Good price on the thermo tower above . . . but it doesn't appear to include the thermostat. They need changing also.

A word of caution on the 8mm (10mm?) Allen wrench socket . . . many caps have been broken by using that alone. I would suggest a rubber strap wrench alone or if necessary in addition to the Allen wrench.

Another suggestion; the bright aluminum housing will look out of place on an otherwise all black engine. I painted mine flat black before installing.

While you are working in there it is a great time to flush and refill with new coolant.

 

Thanks, guys.

On the o-ring idea ... There seems to be no groove or channel in the cap that would confine an o-ring to stay put at the perimeter, so I'm wondering about whether it would seal against the skinny-walled tube that the cap threads onto. (If that made sense ... )

The current cap has a sort of flat rubber gasget inside of it ... covering the full inside-cap surface edge-to-edge.

Has anyone done the o-ring fix successfully?

 

Thermostat and housing:

Welsh Enterprises - New Jaguar Parts, Used Jaguar Parts and Accessories - XK120 - XK140 - XK150 - E-Type - MK - XJ6 - XJ8 - XJ - XK8 - XK - XJS - S-Type - X-Type - XF

They have two listings.

 

The new aluminum housings are set up with the 'O' ring seal but if my memory serves, and it has been several years, the OEM plastic version had the rubber seal you describe. That also may be available from your friendly, helpful, hardware man as a rubber washer. The hole in the middle doesn't matter as it is only the edge that seals.

 

I was thinking of a slightly oversize fat o-ring that would stay up in the cap on its own and not deform when the cap is put on not to tightly. But yeah, from your description, a flat rubber washer seems like a better way to go if you can find one (or fabricate one). Heck, even applying a nice thick bead of red RTV sealer and screwing the cap on would probably work, as long as you let it cure overnight before you use the car again. That got me out of a jam once. Lasted a long time. Then again, you could do it the right way and replace the housing and cap.

 

Come next Spring, I'm on it. For now, seeing as how the weather around here is more like Quebec than NJ, the 'chewing gum and bailing wire' approach may not be all bad.

 

Just remember that the temperature gauge does not give much warning if you overheat, so check the housing frequently.

 

Hi All: I have the new aluminum tower and parts ready to install on my '98, but am not sure the best way to drain the system. Is there a drain stop on the bottom of the radiator, or some other place to drain it?
The motivation for this is that the seal at the bottom of my (original ?) plastic tower is apparently leaking.
Thanks, John

 

And before you ask about the photo in my previous post the car I am talking about is my PURPLE 1998 XK8 conv.

 

The drain is at the bottom right-hand side of the radiator. Large X-slot for screwdriver to turn and open. Careful, it's plastic.

This link should help: http://matt.zenfolio.com/xk-coolant-...tat---v1-1.pdf

 

Mike: That is excellent, thank you.
When I first got the car the convertible top would not work, and the similar step by step instructions that were posted here worked out perfectly !
Now I had better get at it....
Thanks again,
John