My wife & I headed over to the marina to take the boat out and sail in a marvelous 12 kn breeze while watching 5 or 6 fireworks displays around Seattle last night. Mount Rainier was incredibly beautiful as the sun set. I was unprepared for the "fireworks" provided by my 04 XJR as we pulled into my spot in full view of my crew & a host of other sailing buddies.

On the way to the marina, there was no sign of any overheating in about a 25 mile drive with one brief stop of about 15 minutes about half way. Judging by the amount of coolant under the car where I parked, I would guess that something gave way big time just before, or as, we parked. While I couldn't see the source of the geiser, it appeared to be between the Coolant Reservoir & the engine; in other words, if I had to guess, I would say one of the front hoses. The fan remained on after I switched her off & I didn't know it could run so hard. We headed out for what was a spectacular evening of sailing with very unexpected nice, but chilly, weather. We caught an uber home & enjoyed the company of a delightful driver; the ride home was especially nice since we were able to have a few extra Lagavulins since we didn't have to drive (A silver lining if there ever was one!).

This morning, I met the tilt/flatbed truck to bring her home. I started her up & you'd never know anything was wrong & she drove right up on the bed & backed nicely into my garage. When I removed the breather apparatus covering many of the hoses, expecting to find a gaping hole in a hose, I couldn't find it.

I have been reading many really excellent threads about hoses on this site. There is sufficient detail to replace all of the hoses; so, I suspect, this could be a long process with much study, many photos (Aren't cell phones great?), careful staging, parts gathering, etc. After I see what is leaking, I plan to fix if a simple fix (unlikely). Most likely will plan to replace as many hoses as possible including the valley hose which, I understand, is a particular PITA.

As a first step, I was going to pressure test via the expansion/coolant reservoir. I don't think there is much, if any, water in many of the hoses. I topped the reservoir with water. Should I run her & let the thermostat open to fill the hoses? If so, should I do this over a period of time?

Any and all suggestions or advice is much appreciated.

Thanks & best.

 

Hi Steve, so sorry to hear about your baby coming up with a leak. I've been there.

I'd fill the system with just water (since you'll be draining the system anyway). Then pressurize through the reservoir.. Autozone had the pressure tester and Ford adapter. You can just rent for free. Apply pressure up tp 15 psi, but as the pressure increases You'll see the leak immediately. I'd drive the car up on ramps and remove the plaster cover underneath to give yourself full view of everything. If it is the hoses consider changing them all. My leak was in the radiator, BUT I ended up changing everything. All the hoses, reservoir, and water pump. It's not east getting to all these parts and I didn't want to do this job again..

All the hoses were order directly from Jaguar and quite pricy. Unlike parts for my old Yukon. lol,, Hopefully your issue isn't too bad.

 

Thanks, IMPASIUK!
As fate would have it, the pressurizer I borrowed from O'Reilly didn't have the size needed for my car will try Autozone.
Think this is a stupid question, but how do I fill the system when the reservoir holds only a fraction & doesn't seem to let the water flow into the rest of the system. Do I need to to run the engine enough to open thermostat & then let cool & repeat?
Best,

 

Here'e the Cooling System Draining, Filling & Bleeding section from the X350 Workshop Manual:














There's a further section in the manual on pressure filling but that's more aimed at dealers and professionally equipped workshops.

Graham

 

Hi Steve, you can fill the entire system through the reservoir.. There is a procedure (shown above) on filling and bleeding the system... You can begin just filling the system completely through the reservoir until full. Then start up the car and continue to fill until if the water drop in the reservoir until it reaches the proper level. Then pressurize, but if you have such a huge leak you might see it right away as you fill it... Smaller leaks will definitely need to be pressurized. It tougher to find.

Happy Hunting

 

Thanks, Guys! Graham, as my Pappy used to say: "If all else fails, READ THE DESTRUCTIONS!"
Put her on ramp last night, will remove plastic bottom cover later & attempt to fill.

Best, SS

 

OK, filled by removing the expansion tank bleed screw. Tightened bleed screw & put the cap back on.

Cranked engine & let run for 15 minutes; no sign of leaking or steam. Turned engine off after 15 & immediately coolant was streaming on the floor. Water seems to be coming just right (U.S. passenger side) of the expansion tank. Looking down, I could see no water on the tops of the many hoses. I will let things cool down & try again later. Tried looking up from floor & have no visibility of any hose in that area.

Questions: If I were to take the expansion tank, etc. off in order to get a better look, could I likely see &/or feel the hole, assuming it is a hole? Is there any kind of a valve that could be opening? As Impasiak mentioned, if it were a hole in a hose, wouldn't it manifest in 15 minutes?

Thanks & best, SS

 

When I went to try again, noticed a small drip; couldn't determine specific place, but in the same general area as previously described. Below the big hose most visible on the passenger side. Again no water on the tops of any hoses below.

Re-filled & started. Drip continued & increased. After 10 minutes, it was coming down at a fairly good rate. With flashlight, it appears to be the joint where the expansion tank enters the hose or the fitting where the expansion tank inserts.

Unless there is another suggestion, I plan to remove the expansion tank & inspect.

Thanks & best, SS

 

As I was taking the Coolant Tank off, it appears that the sensor at the bottom may have been partially unplugged? Still not 100% sure this is all that is leaking. In removing one of the little hoses, broke one of the nipples. Have ordered a new tank & will see what happens. Should have it in about a week.

Best, SS

 

The coolant level sensor is integrated into the reservoir so a loose connector wouldn't cause it, but the nipple on there that connects to the hose could be the culprit, especially since that jives with the leak location.

 

Nice detective work! The nipple is very weak and they all tend to crack/snap off. The coolant tank is cheap enough to change, but there is a small metal clip that you just pull out first to remove the hose. Looks complicated, but actually it's an excellent design and super easy to remove once you get the hang of it.

I doubt this is the cause. Typically they will slow leak from this attachment, If I was a betting man, I'd say if coming from the radiator side tank. It's probably leak right from the seem.

Good Luck!

 

Thanks, Guys; will let you know what happens once I have the tank back on.

Best in the interim, SS

 

Be careful not to drop that metal clip, could be an issue if you do.

 

What a joy it is to me to have such resources as each of you! Thank you, thank you, thank you!

Why this did not dawn on me sooner, I don't know: A warning light never came on throughout this entire overheating ordeal. As we drove the 25 mi at speeds between 80 & 45 & stopped for 15 minutes at the halfway point; as I parked her and noticed the steam; as I drove her onto the truck; as I drove her off the truck. As I mentioned yesterday, as I removed the Coolant Reservoir, it appeared that the sensor (which I believe is the fluid level sensor) attaching to the bottom of the tank was loose or disconnected altogether; I did not have to unclip it. At this point, I suspect this to be the primary culprit.

As I know many of you have infinite experience compared to me, please let me know what hoses are most likely to go 1st, 2nd, & 3rd if there is any such order. My inclination is to replace the biggest one at the top & the hose config that plugs into the Coolant Fill Tank. The valley hose sounds like a more formidable job & unless, at some point, it indicates to be faulty, I am inclined to let it slide for now. In a perfect world, I would replace all of the hoses & maybe I will; but, I prefer not to look for trouble where it doesn't exist. Any & all advice much appreciated.

Carpe diem, SS

 

Did you try the pressure tester to try and locate leak with cold engine?
Also hook up a scanner to monitor engine coolant temperature and drive it. If you see over 95C, shut er down.

 

Thanks, PanelHead. After I install the tank, I plan to do a pressure test. Will report back.

Best in the interim. SS

 

Returned home to see that my coolant tank has been delivered. Another shout out to Suburban Auto Parts in Troy for a job well done!

Somehow, I thought there was supposed to be an O-Ring where the bottom nipple attaches to the plastic receptacle of the hose. However, there is no sign of one & the new tank didn't have one & the fellow at Suburban didn't see one on the diagrams shown on either the tank or the hose configuration where the tank attaches.
The last 6 of my VIN: G12607

Does anyone know whether, or not, there is supposed to be an o-ring? If so, any idea why it isn't shown? Part #?

Thanks & best,

 

The o-ring is inside the female end of the hose. Should be okay to reuse. I doubt Jag ever sold that as a separate part other than the entire hose assembly.

 

Thank you, MHamilton. I went out & checked again & I think I can feel it with pinky finger. I was expecting something different, but I think it is intact.

The clip that fastens the tank to the hose receptacle, is it possible to put it on "half-way" & then push into place once the tank is inserted? Seems almost impossible to hold the tank in place & then insert the clip. I detached the larger hose from the top of the radiator & it does help.

 

Please disregard my last toopid question. Answer is: Detach breather paraphernalia & insert from above with right hand, while centering with left; then, a gentle push & ta-da.