Hi,

I have a Jaguar XJ X351 5.0 V8 petrol NA which was leaking coolant from more than one place.

I’m (attempting) the repair myself - what I’ve been looking to do is replace:

- water pump
- oil cooler water pump pipe
- coolant crossover pipe, near the water pump
- coolant water heater pipe, at the back

Where I’ve gotten to after many DAYS of struggling:

- I have managed to remove everything except the coolant water heater pipe
- I’ve removed the four T30s connecting the pipe
- I’m now stuck by not being able to disconnect one of the coolant pipes that has these green click in buttons on either side and goes into the pipe (also connected to where the relief valve is)

Access is extremely limited and I’m reaching the limits of my patience

Any advice or suggestions on how to remove that pipe are very welcome!

Also please note I have learned mostly from YouTube and forums (I.e. unless it’s a term or part I’ve come across whilst searching up I will be completely clueless!)

thank you in advance…

Coolant pipe with the green clip bits

 

Keep going as those green tabs need to be pushed in from both sides. Access is limited. When the tabs are depressed push the hose in before pulling out. I generally have to wiggle it around a bit before it comes loose.
Now if the rear water manifold is going to be replaced you could just cut the plastic off where the hose connects and remove the plastic stub when it's out and on the bench?

One other suggestion if you plan to replace that rear rubber heater hose? It has a metal bracket and bolt that's real hard to get to and Jaguar has released a cheaper and simpler version of that hose.

Here is what comes stock. Now I need to be careful as you have the NA 5.0L engine but I think this hose is the same between NA and SC versions. I would check the part number to see if it fits your car.





Here is shorter and cheaper hose used on later engines starting around 2017 or so and without that terrible bolt and bracket which was not needed in the first place. Jaguar never went back and updated the older cars part numbers so this was a lucky find! We had a forum post where his mechanic found this out and started using it on most of his repairs. I currently have this installed on my 2014 XJR so I know it fits the SC cars. The really great thing is this hose is about 1/3 the cost of the one with the bracket.





There is now a brass replacement for the heater bleed port screw too if you want to update that? You can see the black plastic factory one in the above hose picture.





Thanks for posting car info as we do need that. Can you add the year? As you know the 5.0L NA version was only produced for a limited number of years.
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Thank you very much!

Forgot to add, it’s a 2010 (XJ L).

Didn’t know about the brass heater bleed screw, definitely getting that as my plastic one was having issues with leaking coolant too! I have put in a new o ring but didn’t realise I could swap out the plastic for brass…

Will try as you mentioned, to push in before pulling out, etc. I don’t have an angle grinder but I was thinking of purchasing one so if I can’t wiggle it out with the current access I’ll buy one and cut through the rear water manifold.

Wasn’t intending on replacing the rear rubber heater hose - is it a part that often fails like the rear water manifold or is it generally fine but just poorly designed? I.e. would you recommend replacing to the newer/simpler pipe (if it fits)?

 

Up to you but think about it? That hose is now 15+ years old so I would plan to replace all the rubber because of the age. It's not real failure prone at least any more than the other rubber hoses. But if not just plan to keep a sharp eye on coolant leaks and coolant levels.
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Thanks! Have opted to leave as is for now and will keep an eye / possibly look to replace later down the line.

Also thank you the ol’ wiggle push before pulling worked and I got it out. New pipe is in. New water pump is in. Although - when taking out the water pump I had broken the little hose that goes to the air intake. I thought I had bought the replacement but have now realised I bought the wrong part..

Any idea which part number I need for this?


In the background is the replacement part I had bought which I don’t actually need since that part is intact. I need the little tiny hose pipe that is broken in that picture

 

FYI,

You can find an updgraded brass outlet pipe from online sellers.
Use the following search words: Thermostat Outlet Hose (UPGRADE BRASS CONNECTOR) For Range Rover / Jaguar 5.0L 3.0L LR049990

Good luck!

 

Thanks!

Do I use the grey piece to replace the black piece that’s in the water pump outlet? I.e. pry out that black bit from the water pump and put this new grey piece in to fit the brass connector?

 

I would. It will be easier than attempting to reuse the original rigid hose to attach to the flexible coolant hose on the new brass part.

Keep us updated.

 

Thank you both, ALMOST there.


Current stage



Have put in the brass piece with a bit of hose pipe, didn’t want to put too much force in pushing the brass piece in too much. Seemed like it was in the max it would go but kind of looks to me like it’s sticking out a bit?




In putting the throttle body back together I somehow flicked off one of these clips (below) which has disappeared into the abyss. I’ve tried searching “norma PA6 GF50” which is the writing on it but can only find them available in the US. Are these easily available in the UK - do I need to use different search terms?





For reference, this is where I was yesterday..

 

You did not ask but that grey bit of plastic looks like a hose nipple is blocked off inside. That was because of the changes Jaguar did in that area. See you got past that.

The brass fitting has what's called a push-lock fitting. Similar to the heavy duty over the road trucks air brake systems.





You need to pull out the black plastic collar. Then slide the brass end in and then push the collar back in to lock the brass tube in place. If you mess with it a bit you can see how it works. So practice taking it in and out a few times. A lot of times just pushing in the brass part will seat the locking collar.
As your pictures shows it's not yet seated fully in place. It should go in and stop where the ridge is on the brass part.

One note? We have had reports that sometimes you can't get the brass tube to stay tight. Don't know if that's due to different vendors or just variations in the parts.

Can't help on the clip but do you know where it went? We don't see a lot of the 5.0 NA engines.
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Thank you! Was in the process of putting everything back together when I saw your reply. Was painful but managed to pull the plastic collar back and seat correctly as you outlined.


Horrible angle but hopefully shows it clearly enough. It also changed colour from black to grey since I dropped the black one (which came with the new water pump) - fortunately the brass fitting also came with a replacement (the grey one)

Didn’t realise about the grey plastic connector bit. I went back to the original one I had, performed surgery, and have used that instead.


What I’ve done






Managed to find the clip when I was looking for the black plastic collar!


If helpful the collar sits on two pipes that come out of the coolant reservoir (the pipe that’s at the top of the coolant reservoir and then it splits into two)

This one from the coolant reservoir (bottom right of photo)

 

Slightly heartbreaking but turned it on - there was smoke or steam so I immediately turned it off. Not sure the cause but will find out later I’m sure - maybe leaked/spilled coolant?

in other news, that brass fitting didn’t fit so well

 

Yes that has been reported and sometimes you need to go back to the plastic version but again I don't really know why? Did you pull on the connection to make sure it was grabbing good before you started the car? That usually will tell you if it will be a problem.
Coolant is Dex-Cool and that's usually orange?
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PA6 GF50 is the type of plastic that clip is manufactured with- Polyamide #6 glass fiber reinforced 50% which is nylon that is impregnated with glass fiber for structural rigidity. It's not a part number.

 

I pulled in it before and it had seemed fine, but oh well, I’ve ordered the plastic part too so will try fit that when it comes.

Not too sure with the coolant in all honesty so I had bought this universal coolant that says it will mix with any existing coolant already in the system…. Hopefully okay?😅😅😅

 

Correct coolant is one matching JLR specification STJLR.651.5003.

DO NOT mix OAT coolant with other types.

 

Thank you everyone, I managed to put it all back together again. I flushed out the prestone coolant and put in dex cool. The brass fitting didn’t work out so great for me and neither did this new pipe, maybe just me?



New part - there was no way this was fitting onto the crossover pipe


What I ended up doing was swapping back to the black three-way connector (which isn’t blocked off on one side), taking out the little plastic right angle piece from this new pipe (the piece that goes into the water pump). I stuck that plastic bit into a bit of pipe and connected the water pump back to the throttle body (how it’s originally connected).



I was worried the new grey collet that goes into the water pump was going to be problematic but so far so good. I ran the car for a bit and test drove and is okay so far - I do need to pressure test it which I’ll do today/tomorrow. But also need to get on with replacing the rear wheel speed sensor now so the dash doesn’t look like a Christmas tree…