Jaguar X308 coolant leak

[Baryonyx]

Afternoon,

My X308 has, over the past couple of months, occasionally given a low coolant warning light. I'd checked the coolant level on the occasions that the message came up and noted that it stayed resolutely full. Suspecting a duff sensor, I decided to keep an eye on it and have it looked at when the car was in for servicing.

However, this morning I got home from work and noticed that the engine ran the fan for about thirty seconds after switching off. Thinking this was unusual, I popped the bonnet for a look around and could hear a hissing of a hot fluid. Looking at the front of the block, I noticed what appeared to be a small coolant leak, with a wet film having boiled on the hot engine. It looks like it's just below a feed from the radiator, see the picture:




It appears to have leaked around the clip on that fat rubber hose on the right hand side. Is this a coolant feed from the radiator? On checking the level of coolant this afternoon the level had definitely dropped from where it had stayed resolutely for a while.


Diagnosis? Likely a leaking hose? It is an old, high miler after all. What should I expect to pay getting that fixed at a garage?


I'm going to get some coolant on standby in any case, what is the type specified for the car, and will I need to go to Jaguar for it?

[Baryonyx]

Thanks Steve. Looking at the parts online, I think the leak is coming from around the clip on the thermostat tower bypass hose (I think that is what the fat hose is). It looks like it's leaking around the seal, so maybe the hose is worn or the clip is failing. Is it an easy job to do at home, or better left to a professional? I'm reasonably confident I could switch the hose but the thermostat tower change looks tricky. Where is the drain for the coolant if you're looking to empty the system?

[Baryonyx]

I might try that then. As I say, it's evidently a minor leak but I'd rather clamp it down if I can.

Something like this:

http://www.amazon.co.uk/ASSORTED-HI-GRIP-CLIPS-9-5...

Then it looks like you've at least got the solid steel ring clip rather than the ones with perforated bodies.

I'll get a set on order.

[Baryonyx]

I presume then you were thinking of something more like this?

[Baryonyx]

Turns out I might have been wrong about the hose. On Boxing Day, I took the car over to my mam and dad's, explaining the issue of the coolant to my dad as I arrived there. We had a quick look at the car, since I'd just turned it off and under torch light, I was then able to see exactly where the coolant was coming from. It wasn't the hose, rather it was the cap next to it (the thermostat housing cap). There was a thin bead of coolant running out, dribbling down onto the block and sizzling off.

I've fitted a replacement cap today, as my reading suggests the cap can become worn or crack and imperfections in the thread will cause a leak when the coolant fills the tower under pressure (I note when the car is cold, the coolant level in the neck beneath the cap is somewhat lower). Hopefully this will fix it, otherwise it might be time to switch the cooling tower itself to an aluminium piece, and that is something I don't think I can do at home.