Boy this is frustrating.

I recently pulled the radiator and had it re-cored, but since my steering rack is starting to leak like the Exxon Valdez I haven't been driving the car. Yesterday was such a nice day that my daughter asked me to pick her up in the convertible so I went ahead and drove the XJS. This morning I noticed there is bit of coolant on the floor.

I assumed there was a hose that might need tightening, and I took a look this morning but couldn't figure out where the coolant was coming from. I could feel the top of the under scuttle was damp. I removed the under scuttle and see some evidence of coolant but it wasn't leaking anymore. I started the engine, but still no evidence of leaking.

I lowered the car and took it for a drive to get up to temperature, and pulled into a dry spot in the garage and took a look underneath while it was running -- no dripping. I shut off and came back 15 minutes later, and still no dripping.

Came back much later and there is a puddle on the left between the fog light and the license plate. I took a picture of where the coolant is dripping from and if you look at the picture there is coolant across much of that seam below the radiator and collects in the circled area and drips from there.

There is no evidence that coolant is coming from any hose, pressure cap, or either the bleed port or the air purge port.

Is there anywhere else that could be leaking other than the radiator itself? I'm screwed aren't I? I'll have to R&R it all over again?

 

I too had a mystery leak that didn't seem to be coming from any hose

Finally discovered water pump was weeping it out and it was running down the block where you really couldn't see it.

Changed the water pump and all was well

Fwiw
Good luck

 

That means coolant has dribbled off the front of the radiator. All the hoses connect to the back of the radiator. The vent banjo is on the top but you would see that leak by looking down from above the cross panel (have you done that ?). Could be that coolant has dribbled from a hose along the metal of the pipe and into the core and gone forward, but doing that without witness of drips from the rubber section of a hose behind the radiator as well, is unlikely. Sound like you need a pressure tester and take it up to 15 psi and watch what happens and where coolant leaks.

 

Before anything else, IMHO.....

Clean all the wet areas. Go 'round and re-tighten all clamps associated with your recent radiator work, and make sure they are properly positioned.

Road test and re-check.

I've been tripped up more than a few times over the years by hose clamp issues.

Cheers
DD

 

Thanks Doug, and yes that occurred to me too. I did just that, and still no love.

I have seen clamps fail where they can't be tightened fully, but I can't detect any leaking around a hose.

I called the guy who did the re-core, and he tests the units to 22lbs psi. He said he'd fix any issue w/o fuss, but I don't want to pull it if it's something else.

 

Well after a couple of warm up/cool down cycles (and a burn or two) I think I may have found the issue. The small hose that goes in 90° just above the large lower radiator hose needed more tightening than I'd done either in the first place or when I did the recheck. Won't know for sure until after a full cool down.

Quick question, do I need to re-bleed the system even though I've lost very little coolant?

Thanks

 

Good find.

If you have only lost a smallish amount, let the system purge itself. It is capable of doing that providing there is ample fluid in the atmospheric tank in the LH wing aperture.

If there is doubt about how much has been lost, bleed it.