Hi all,

My 90 xjs conv has a new leak. It appears to be under the car between
the cat converters. It isnt hot. I suspect it may be the heater core, but not sure. Any thoughts?

Tony

 

You're seeing actual coolant on the ground? Or clear water?

Are you sure that what you're seeing isn't normal drainage from the A/C system? The drain tubes exit the floorboards in the the area you mentioned.

Cheers
DD

 

Yes, it is a thick sweet smell coolant colored fluid. Comes out in a very steady stream.

Tony

 

Well, I'd say it's either the heater core, with the leak comng thru the a/c drains, or one of the heater hoses. Or perhaps the heater valve.

From your description it sounds like a big leak. The heater hoses and valve are not especially easy to see but you should be able to run your hands and finger over them and feel for any wetness. Wait for the engine to cool down a bit

Cheers
DD

 

Hi all,

I was able to take a closer look. The hose that has sprung a leak near in the engine bay is located at the back of the engine. It's a small hose 9/16 or so that tees off of a cross pipe at the back of the engine. It leads down through the fire wall and under the car and seem to connect to a metal tube above the cat converters.

The end in the engine bay was easy to get off but the other end appears to be a bigger challenge.

Any thoughts???

Tony in NM

 

Cross pipe?

Are you referring to the 1" diameter aluminum pipe that connects to the left and right intake manifolds? If so, that's a vacuum balance tube. It has a small hose attached that runs downward and rearward...clear back to the ECU in the trunk.

It should never have coolant in it.

Cheers
DD

 

Ok, hope its not the culprit. Must be the heater hose under it.

Tony

 

Doug isn't there some sort of valve underneath it? I never really looked at it to see where it went or what it did, but the bottom end of the T had rust like there was fluid flowing through it. Maybe it was just dirty from something else.

EDIT:

something I found called it an air diverter check valve. Im guessing it was just dirt and gunk and not rust from coolant.
probably heater hoses then

 

OK, I found the leak. It was, in fact, a a heater hose between the valve and firewall. As with all things Jaguar, it was a PIA to get to, get off and the new one put on. I drove the XJS around and no leaks. To top that off, the cooling system seems to be keep the engine temp under control.

Thanks for everyone's help,

Tony