Is the water reservoir in one piece or two?


I have noticed a small amount of water/red coolant on the 2 black plastic screws that attach the black wire to the tank in the attached picture.


I wondered if the clear lower part and the black upper part of the tank come apart and if so maybe the gasket needs replacing.

 

Unfortunately the tank is a one piece item and can suffer from hairline cracks making leaks difficult to verify.. there is a few threads in this section about the coolant tanks, and checking for leaks - it would be well worth a visit to this thread : https://www.jaguarforums.com/forum/x...oolant-115783/

 

Howdy,
Have a look at this thread and discussion; https://www.jaguarforums.com/forum/x...re-cap-125477/

It will be helpful to you and give answers your query.

 

Here's another recent thread with pictures of stress-cracks in the reservoir nipple and bottom:

https://www.jaguarforums.com/forum/x...solved-123238/

When the bottom of the reservoir cracks, it leaks from the bottom mostly when the coolant is hot, creating pressure like a boiling tea kettle. I doubt this is the source of your leak because the leaked coolant appears near the top of your reservoir.

When the nipples crack, they leak when the engine is hot enough for the water pump to circulate coolant into the reservoir thru the two black nipples near the firewall / passenger compartment. For your reservoir, the leaked coolant is near the tank, so check for leaks around these these nipples.

What's baffling is that the two black nipples are on the firewall side of the tank, yet your leaked coolant residue is on the opposite, battery-side of your reservoir.

If the cap was the source of the leak, the coolant would flow thru a safety vent in the side and bottom of the reservoir next to the brake master cylinder. Again, that's below your coolant residue.

Try this trick: Run the engine long enough to heat and circulate the coolant, then use a dry paper towel and carefully touch around the nipples and sides of the reservoir to see if and where the dry paper towel becomes damp.

If you don't detect any leaks, are you sure you're loosing coolant recently? Perhaps the residue has been there since the last time someone topped off coolant in the reservoir.

Please let us know that you find.

 

Thank-you so much Steve, Lcgi and dwclapp for the helpful replies and links.


I have read through the threads and took it out for a drive this morning after thoroughly cleaning and drying the whole area.


When I opened the bonnet I could hear a hiss and it was coming from one of the 2 upper nipples where the small hose attaches.


I can see where the tiny leak spits out water and it runs to the front of the reservoir where I noticed it yesterday.


Using a paper towel as suggested I noticed there was a minute amount of moisture around the other nipple near the firewall.


The cap is not leaking.


I had been looking online to buy a new expansion tank and the UK and USA are well served in that respect with Ebay but I am in South Africa for a few months and there is nothing for online that I can find.
I could order one from the US or UK but regulations are very tight here and I have been told it would get seized at customs.


So my plan is to try and patch the 2 leaking nipples, I read of some success on this website with JB Weld, I tried two car spares shops this morning with no luck so bought some Q-Bond that came recommended.


I will wait to see if there are any tips before attempting the repair but I assume I must wait for the tank to cool, make sure the area is free of dust and grease and rough up the area a bit with sand paper, then apply the Q-Bond making sure the hose will still fit over the nipple.

 

Glad you discovered where it's leaking and have a plan to address it. Look inside the cracked plastic nipples and you should see brass inserts. I've never tried this, but if the brass insert is also cracked, perhaps you could carefully drill it out and insert a new brass sleeve, maybe using some glue to lubricate the brass sleeve as you slide it into the nipple.

Alternatively, some folks completely replace the plastic nipples with threaded plumbing fittings, for example:

J-Rock in this thread (at the bottom):
https://www.jaguarforums.com/forum/x...epairs-126186/

Paulc732 and MattSteele in this thread:
https://www.jaguarforums.com/forum/x...solved-123238/

You'll likely find more examples with an advanced search on words like "coolant nipple fitting" in the X-Type forum.

One final thought: Until you have confidence in your solution, carry a jug of water and check your coolant level regularly. A coolant leak is a nuisance. An engine running without coolant is a disaster.

 

I repaired this last week and have had a few 20 minute drives since and the repair seems to be holding up so far.
Only time will tell if it was successful for longer drives.


The expansion tank definitely needing taking off as the hole was on the underside.
I gave the whole tank a good clean and used the Q-Bond.


Thanks again for the help.

 

Thanks for letting us know the repair worked. You may want to keep a jug a water in the car and routinely check the reservoir, just in case. If the Q-bond eventually springs a leak, you still have plumbing fittings as a Plan B.