The only real issues I've ever had to deal with on the 3.0/5.0 involving coolant loss is the engine coolant pump and plastic pipe behind pump. The pump bearing fails and generally leaking out from the pulley bearing at mid rpm or load situations. If you looked for coolant on an early issue, most likely would not find being the coolant is blown away from the faulted area.

It's easy to find by using a pry bar or long screw driver to see if there's play in the pulley. If pump was diagnosed faulty, the pump+small plastic tube under charger+o-ring would be replaced. If the pump had large visual signs of a leak then sometimes even the belt would get replaced to avoid a chirp.

To diagnose any other leaks, use a pressure test. To refill coolant, use a vacuum bleed..the vacuum bleed will also double check to see if any clamps are leaking when pulled versus push.

 

In my case it was definitely that little/thin plastic pipe over the top of and in front of the cross-over pipe, part of the expansion tank overflow system, that is/was the culprit.
It simply became very brittle and eventually fell apart, and then the cobbled up replacement pipe developed a small split due to a too small / too tight clamp cutting into the rubber.
The mechanic who detected the broken brittle OEM pipe commented that it was a terrible design, mainly because of the type of plastic used which was always going to become brittle after a few years due to repeated heat cycles.
The strange thing is I'm not aware of any other reports of this pipe failing, so why just my car????

 

The common issue with plastics getting brittle is age OR heat. Most often if an engine has overheated or ran of the verge, you will have an accelerated aging of the rubber and plastics in the engine bay.

 

A few days now and about 200 km since my MacGyver fix of the coolant pipe and it's working perfectly, not a single drip/leak.
So a shade tree mechanic heads up for those who may be interested - if you have a small cut or split in a rubber (and maybe plastic?) coolant hose, slather the cut/split in RTV silicone sealant, wrap it in a piece of Velcro then tie a zip tie nice and tight over the top. Works a treat, and may possibly work for other fluid hoses as well (brake, oil etc).
Of course this should only ever be used as a temporary repair until the dud hose can be replaced, and make sure you don't get any of the silicone sealant inside the hose.

 

A little update.
The shade tree mechanic fix didn't hold up, after a few more days it started to leak again.
Long story short, I cut the end of the hose off where the split was, just the last 5 or 6 mm of the hose so plenty of slack for the hose to still reach/fit OK, and whacked a steel hose clamp on it. Hey presto, after several days' driving no more leaks!
The replacement OEM hose rolled up this morning so I had a look at fitting it myself, but as I suspected a couple of the clips/fittings are a bit beyond my expertise. One is extremely difficult to access and another looks as though I would have to destroy the original clip to remove it, with no guarantee the new clip would then work.
So I've decided to stick with the non-OEM replacement hose for now and keep the new part in reserve if I ever need it.

 

The Over flow lines from the reservoir that run to the front of the engine are being smothered by the heat from the engine and are turning them "brittle" like plastic or glass, i just had to replace mine on my 15 F Type, ( check them because if they snap it will leave you stranded) . Good luck.

 

Will all f type years suffer this same fate with the brittle lines or did JLR change the spec somewhere along the line? Also, my 2011 XF SC had the leaking water pump as did many others. Did JLR buy these by the trailer load and is using up their supply? What year does the water pump leaking issue resolve if at all? I have about 20 months left on my warranty with only 15.5k miles and am wondering what I'm in for post warranty. Thanks.

 

There was a TSB from 2015 for water pump issues which I have attached, it engines shows a range of VIN number of affected vehicles, both F Type and others with 3.0 and 5.0.

With regard to the plastic overflow pipe unless there has been a replacement part that is likely to be much more durable then I would look to sourcing replacement pipe of an entirely different material. As has been pointed out failure of cooling pipes leads to you being stranded unless you have access to coolant and can affect a temporary repair.

My previous Jaguar was a 1993 XJS 6.0 V12 the first cooling system hose to require replacement was the feed to heater at the rear of the engine. It occurred at twenty two years after manufacture with 120,000 miles covered. Also consider the engine bay of V12 Jaguars, especially in XJS are renowned for being extremely hot environments.

Put simply, my opinion is that any hose that requires replacement in under ten years / 100,000 miles was simply poor design / material specification and not fit for purpose.

 

I had to have many of my coolant lines replaced after replacing a leaking water pump and still experiencing coolant leaks.... happened roughly July last year. Good news is the parts aren't particularly expensive, and it was only a day of labor.

 

Addict, could you add your car year, model, etc. to your signature line? Trying to get everyone to do that.

 

I just recently replaced almost the entire cooling system on my 15 R. My water pump went out and I took that opportunity to replace everything from the thermostat to the hoses, orings, and lines. Jaguar did supersede a couple parts in the cooling system, including the crossover pipe and the pipe that runs under the charger. The overflow line gets really brittle over time with heat. Barely touched it and it exploded. That made me just change everything out.

 

Hmm, The P.O. and I ran the car with the engine cover off (since 4K miles, now 18K). I wonder if mine will last longer?


Now I'm afraid to touch it, though....

 

Did you do it yourself or have the dealership do it?

 

I do all my own work, that's how I know it's done right lol.

 

Someone Posted a Temperature Test with and without the shroud (engine cover) and the difference was substantial, like about 40 degrees difference. I will be leaving mine in the garage.

 

 

Have you ever posted a picture?

 

Lance, you have to be careful with IR thermometers - some surfaces like shiny aluminum don't give reliable results. I have a fancy one at work where you can enter the specific material, so it can compensate for wildly different emissivities...

And yes, Lance's engine is shiny...

 

I assume you are talking about the line I highlighted on @Unhingd pic? I just looked at mine and it has a webbed 'cozy' insulating most of it.


PS: That intake looks good. It is not just polished...the casting's 'bumps' have been smoothed out. SWEET

 

I'm sure that would make a tremendous difference on the heat issue, i'll have to find some of that insulation wrapping, although once you close the hood it is so close to the engine it'll still be a concern. Thanks for the diagram Carbuff2, like the polished job, looks nice.