I had just replaced my coolant reservoir...yep it was leaking at the nipple, when just 3 weeks later, I noticed another small leak near the thermostat. Had just purchased a new Bosch DCCV ($82, Autopartsworld) and was planning on changing it, the thermostat, the o-ring on the coolant tank and flushing the system. So this new leak was coming from a pastic housing/connector and I can see why. The fitting seamed pretty flimsy, I think it may have been part of a recall that slipped through the cracks... not sure. Anyway, the dealer sells part #54920 and for $250 you get the preformed radiator hoses(3 or 4), plastic fitting, jag thermostat and a new metal housing all in one kit. With all the hoses you get the price wasn't bad and along with that comes some peace of mind. So if any of you are thinking about that 5 year flush, a new DCCV or replacing the thermostat check that plastic housing!! If you're in this for the long haul you may just want to do your radiator hoses in one shot, much better now than on the side of the 405 freeway. I started to say during rush hour but it's always rush hour there.

 

I have a pinhole coolant leak, newly discovered today, coming from the top of the housing that the T/stat housing bolts to. I'm trying to figure out the proper name of this housing. The closest I came is a "coolant outlet pipe". I saw at one parts house there is an aluminum replacement kit but it's for 2000~2002 and I have a 2003. Is this the problem you had?

 

The fitting that was leaking was a plastic union of several hoses and I think that might be what's leaking on yours. If you havn't already changed out you thermostat, check with the dealer for the kit I mentioned above it comes with a new thermostat housing plus several hoses. You'll solve a lot of future problems with it. Best of luck.

 

Thanks Dirk, I think I will call the dealer just to pick their brain on this one. BTW- here's the only site I found so far that has an accurate picture of what I need. http://www.britishparts.co.uk/.sc/ms...-%20THERMOSTAT

 

Cobbler,
I thought you had the 3.0 six cyl....my bad. That part looks different than what I changed. Let us know how it goes.

 

Here’s an 03 jaguar upgraded housing for $55.00 (this is for the 4.2L)
http://www.carpartsdiscount.com/auto/parts/2003/jaguar/s_type/thermostat/thermostat_housing.html?3593=121230

here’s a link for 05 housing for a v6 3.0L for under $60.00

http://www.racepages.com/products/?N=4294962486&Ntt=Jaguar+S+Type+Thermostat+Housing

hope that helps guys..

tdc..