So my XJ8 vanden plas has been eating coolant as fast as I've been pouring it in. No left over residue, no leak anywhere... The tech today said its most likely the thermostat housing. He said it can all leak out around there, and we would never see a thing. Replacement part is $70.00 but the labor, dear God. Total is going to run me about $900 USD.

 

The housing has a history of slowly leaking without getting wet but so do other places. I would ask them to do a pressure test to verify. The water pump is also a likely candidate. It will lose a lot more coolant than any of the others without a puddle. It should be changed anyway unless you have a record of that in the past few years.

I am sure the quote included a coolant change which is probably appropriate to do but as a Certified STM the labor cost is way out of my range.

Perhaps a quote from an independent Jaguar shop to include a pressure test, replacing the water pump, a METAL thermostat housing, coolant flush AND fixing the leak. Four hours max IMO.

 

If the housing is old then you can try these guys for a great aluminium product. http://www.welshent.com/product_info...th=722_764_767

You can do the rest yourself.
Regards
Gareth

 

Replace Thermostat, housing and seals - Labor $125
Parts - $397: Thermostat housing, cover, seal, pipe-outlet, seal - water outlet, thermostat, cap-thermo housing, cap-pressure
Total - $522 plus flush and fill ($190 for total of $712)

For another $260 parts and labor, do the water pump.

Replace EVERY radiator hose, heater hose, seal, water pump - $1950 + radiator flush and fill ($190) - ask for a free loaner or enterprise rental at this cost -- screw type pipe clamps can (and likely will) break any plastic parts like the thermostat housing -- OEM clamps are spring type.