Hi guys - I have a 1997 XK8 Convertible out here with me in Kharkiv, Ukraine. Had various bits of work done out here over the last few years, mostly cosmetic bodywork (i had the car stripped to metal, all the rust and dinks sorted and a full pro repaint in original colours plus full anti rust coating underneath for, basically, small change a few years ago) and general servicing with a bunch of local friends who have a car repair company, last thing done was a replacement of the serpentine belt which snapped whilst close to home.

It went on the highway about 200 yards from home, managed to coast the car to a stop around the corner. Belt was badly worn (probably on the car from new) - had a new belt shipped out plus new and improved replacement rollers. The guys from the garage did say that it looked like the coolant system was over pressured.

Some time before this I started having problems with the heater in the cabin - basically it seems to only push out ambient temperature regardless of the temp setting/AC (so totally useless when it's -8 here in the winter).

Recently started having some other coolant issues, and I'm now a bit lost. I do not think these are directly related to the serpentine belt issue, and I do not think its the head gasket - the car runs fine and have taken on a few long-ish (2-3 hour) runs since then, and not had anything happen - except as below.

1. I am losing about a pint of coolant every so often - sometimes the car runs on short runs for a week with on loss at all, then i will have a couple of days losing a pint each time

2. Yesterday after a run out of town and an hours drive back, when i stopped the car near home, i saw for the first time a continuous leak of about a pint from somewhere near the recovery bottle (behind the drivers side front wheel, just behind the plastic cover, looks like it is coming from somewhere near the bottle, but not exactly, as I understand the bottle is actually further back nearer the engine wall, and this looked like it as more or less exactly next the the wheel) - the leak was coming out fairly fast - too fast for it to be continually leaking from there - it must presumably only happen occasionally (or suddenly got much worse!)

3. Apart from the coolant low warning coming on occasionally (before i have topped up the expansion tank) the car does not seem to overheat (and it has sat in traffic a few times without issue) and i detect no engine issues, and no oil in the coolant or vice versa no scum in the oil - that i can see. engine is running smoothly with no loss of performance and no sign of white smoke from the exhaust.

So - does anybody have any ideas what could be going on, and how safe it is to drive? I'm a long way away from the UK, so have limited options - there are to my knowledge no approved Jaguar service centres out here! my local friends with the garage are great, but do not know the car much more than the work they have done previously (oil changes, bodywork, suspension etc)

Could it be a failing thermostat? leak in the pipework around the recovery bottle - or is the loss I saw some overflow feature - i.e. its meant to do this if there is over-pressure somewhere? failing water pump? expansion tank is not leaking as far as i can see, but could it be a faulty cap?

If I was in the UK I might be cautious and replace everything, but that's not really an easy option out here - it could take months to get the parts (it took nearly 2 months to get the correct belt and rollers) and its expensive to ship stuff out. if it's the water pump and/or thermostat and it's a good idea to replace both, are there non-jag alternative parts? I might have better luck finding those here, because Jags are as rare as hen's teeth in Ukraine, and as far as I know I possess the only XK8 convertible this side of Christendom - can i find an analogue part for any of these?

Thanks!

 

Hi, I am sure more knowledgeable folk will be along to advise you soon. Why don’t you remove the wheelarch liner and have a look at the recovery bottle and Pipework just to make sure all is well. It won’t take long or cost anything.

 

Thanks Brinny, I will if I have to, it's just a bit awkward as I live in the city centre and I don't have off road parking, so I will have to find a friend with a garage and move the car there to do it (it's hard to explain unless you have ever been to a Ukrainian/CIS country) and road side repairs will attract a crowd... I suppose I'm hoping that there is a more obvious answer - because it's clearly not leaking whilst the car is moving, only it seems when I stop and turn off the engine

J

 

It sounds like you have a couple of issues so lets start with the coolant loss first. It sound as though you have had a lot of repairs done and it is possible that the hoses to the coolant tank are not installed correctly. Follow the link below and scroll to post #7 not the way the coolant hoses are installed. If one does not cross over the other then change the way they are installed.
https://www.jaguarforums.com/forum/x...d-hose-233948/

Now for heater problem. First while running press the button on the climate control center for outside temp. Is it close to accurate? Next push the temp up control until the screen reads HI. Do you have heat now? If the outside temp reading isn't close and the heat comes on when placed at HI then most likely the "ambient air temperature sensor" is defective. It is mounted low under the front bumper and senses outside temp.

 

Does Ukraine drive on the RHS so is the car driver set up RHD?

From what you say, I think you have an issue with the coolant atmospheric recovery bottle. Good explanation from Youtube’s Father and Son channel ODR. Link below.


Most forum members find the expansion tank cap is the cause of this as it’s effectively the valve that controls the coolant system’s pressure. Also seems only to last approx 3 years before playing up. I cleaned the valve in the cap and that fixed the problem for a short while, but then the cap’s fat washers/O-Rings went soft and it was easier to replace the entire cap than find replacement O rings.

Good luck

 

The Atmospheric Recovery Bottle is inside the rear the front wing (arrowed in red) but the overflow outlet (arrowed in green) exits close to the suspension.



If it is filling and overflowing, there must be considerable excessive pressure in the system. A faulty Expansion Tank Cap will relieve this causing coolant to pass into the Atmospheric Recovery Bottle but there must be another reason for the random and excess pressure. I would test the thermostat for correct opening/closing.

Graham

 

Thank you all very much - all very useful!

I think because I am replying from Ukraine every time I log in I get that bloody Cloudflare "I am a human" thing and have to spot all the airplanes or umbrellas...

Firstly - my car is a UK Jag and so I'm driving on the wrong side of the car (been here long enough that I don't drive on the wrong side of the road thankfully) - it's fine except that overtaking lorries is a bit of a challenge... Thanks for asking David - looks like we have more or less the same car have a few clients in your part of the world (I run a e-commerce software development company here in Ukraine)

1. I checked where the 'leak' is coming from and it's definitely the green arrowed hose - i.e. it's not that the bottle is cracked or split, it was obviously expelling the excess coolant out of the overflow pipe (it was running out almost exactly behind the wheel looking side on, not from the location of the recovery bottle. I haven't had the chance yet to remove the plastic cover yet to inspect the bottle itself - will try to do that tomorrow if I can.

2. I took the car out for about 30 min today, topped up the coolant with about 1 pint in the expansion tank, no signs of leak/overflow when I got back and no sign of overheating (the engine seems to give off a lot of heat from underneath the car - I can feel it with the roof down if I put my hand out of the car at lights - but I'm guessing that's normal...) I know the temp gauge is kind of 'fake' but I have actually never had it rise above normal

3. Inspected the expansion cap - it looks fine, clean and the valve appears to be working, with a bit of pressure I can push it down and it releases OK. It is a few years old, I actually had a cracked expansion tank about 5-6 years ago when the car was in the UK, and I replaced it at the time with a new one from some online Jag parts dealer. Rubbers look sound

4. I don't have the expansion tank from the picture that avern1 directed me to - I'm guessing the image is from a more modern XK - I have the 'old style' one and it looks to me like the hoses are connected all correctly - the back one goes to the recovery bottle, and the front pair go to the thermostat and the radiator (in that order rear to front )



5. Checked with my mates from the garage - they changed the thermostat maybe 2 years ago, its the old plastic thermostat body, not the aluminum replacement one, but it looks to be in good condition and no sign of cracks or wear. I don't know if it's worth replacing anyway and I don't know if there is a way I can check it visually to see if it's ok?

6. avern1 - I haven't tried the heater test, its going to be tricky to tell, as it's definitely pulling ambient temp right now, and here in Kharkiv it's +32 outside, so it's hard to know what might be hot 'HI' temp compared to the street!

So - could it be the coolant pump? I really don't want to just replace parts randomly without some idea what might be the cause, unless I really have to!