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Today I got the Engine Coolant Low message appear en route to Sainsburys. It then went off before i arrived though. I stopped there and could smell burning, which i suspect was burnt coolant. I took time doing the shopping which in the current climate is unavoidable and when I got back to the car check the level which was well below the minimum although still some in the header tank. I had some left in the boot which I used up to top up but did not quite make the minimum level. I also noticed leaked coolant underneath as well as what looked like residue at the front corner of the engine nearest the pipe from the header tank. (driver's side) That is my suspicion where the leak might be. hoping maybe a pipe that is very easy to change. I drove the couple of miles home with the warning light and message coming back on but the burnt smell was back by the time I was home. No new leakage under neath though, nor was there any from outside home from before although I going to look again tomorrow.
The header tank is a couple of year old so pretty sure it is not that.
However, I do recall noticing a similar smell previously but not as strong. Also, was I now consider a precursor, I had the Engine Coolant Low light on a few months ago, so i topped up and saw some residue round the filler cap which I cleaned off and was checking each time before I used the car for a while. The level remained steady so I thought the cap must have been a bit loose. I must have done over 1,000 miles since then.

In my experience, thermostats usually need changing every 80k miles.

Obviously you need to have a good look around the front of the engine as a starting point. Investigation is key to diagnosis before plunging in and buying parts. Check the electric circulation pump and fuse as another prime point.

Mike K

Thanks Mike, any of those could be a cause. The fan had kicked in though both at Sainsbury's and back at home.

I took the engine cover off this afternoon and had a look, there looks to be dried coolant residue on the first bolt nearest the front of the offside and some more a bit further back still wet. Also a few drops on the under tray which don't really help to isolate as it will have run down.
I could see a patch on the road further underneath but could not tell whether that was lost coolant so may be a red herring. At the Sainsbury's car park, the coolant patch was right at the front.
Certainly not wanting to risk driving.

Again in my experience, the only times you should hear the fans running is when you have low coolant. That`s a good pointer to a leak somewhere. Now you have to find it!

Mike

I believe the prime suspect is the radiator if the spot where the coolant appears to be coming from. Or a pipe going there.

The radiator packs are very prone to corrosion especially when they age. Typically being aluminium, when they corrode, pressure is generated within the metal micro structure and poof, you have a hole! The same goes within the heater exchanger matrix for cabin heating. Don`t you just love the smell of curry!

Whilst K-Seal or similar products added to the coolant system often save the day and a load of cash, one has to balance their use against any potential coolant system sludging that may later occur. That said, I had a persistent leak on my old V8 S-type which was permanently fixed with K-Seal. The end of a problem...certainly in my ownership.

Have a good look at the plastic pipes around the front of the cylinder heads and also around the thermostat housing. Plastic parts fall to bits in hot situations so a bit of investigative work in that area might be beneficial.

Mike

Some piping does look a bit past its best but I have to assume the radiator is most likely as it I over fifteen years old assuming it is the original. The one of my Coupé needed replacing at a bit over ten years old which makes me suspect this.

Are they any radiators better of are they all much the same? I believe later ones are slightly different too.

All I can advise is fitting a genuine, Jaguar OE part and avoid after market units which may not meet a decent quality standard not to mention having infuriating fitting issues! ie pipes or brackets in the wrong place!!

Mike

Had a look round and SNG do two versions, presumably both are fine. Also seen same part number although ending in HE with Moss which is for later models so might not be for mine.

Go on the VIN identifier of the car for the correct part. Manners or Barretts can advise suitability.

Rad pack changing is quite a job. Oil cooler, PAS cooler, transmission cooler, (XJR inter-cooler rad) pumps and other ancillary parts bolted to or around the engine coolant rad may conspire to complicate the job. Obviously change as many aged parts such as the thermostat or suspect hoses as a matter of course. You will also have to remove the bumper cover which can be quite a job due to the inevitable corrodes spring clips and bolts. Access to all parts can be rather frustrating especially if corrosion is rampant.

Mike

Will go with advise on the radiator and also look to have any hoses that look past their best changed also. Assuming of course it is the radiator. Took it over to the garage and broke down literally the wrong end of the road. It cut out and would not restart, or did and immediately cut out again. I topped up with boiled water before I left from a 5 litre coolant bottle, where I broke down I topped up again, it having lost the same again. This seemed to promptly disappear so let the heating on full in the car to try and manually cool down. Fortunately the recovery were quite swift so I let them get my to the garage.
Tomorrow I should find out how serious it is.

Will go with advise on the radiator and also look to have any hoses that look past their best changed also. Assuming of course it is the radiator. Took it over to the garage and broke down literally the wrong end of the road. It cut out and would not restart, or did and immediately cut out again. I topped up with boiled water before I left from a 5 litre coolant bottle, where I broke down I topped up again, it having lost the same again. This seemed to promptly disappear so let the heating on full in the car to try and manually cool down. Fortunately the recovery were quite swift so I let them get my to the garage.
Tomorrow I should find out how serious it is.

There is a guide to changing X350/358 radiator at
https://jagchat.net/thread/2048/radiato ... e-x358-xjr
If I can find the original photos, I will update them via a new image host; tinypic has died.
Euro Car Parts supplied an OEM radiator for £117.

Thanks for that. Would be interesting to see the article with the pictures.
At the moment the XJ is being looked at and I am waiting for the update. I have the impression it may not be the radiator though.

So it turned out to be the thermostat housing and a pipe connecting to it.

Went and collected earlier and so far so good. Of course early days so far and need to give it a good run to be sure.

I`ve heard of that issue on the 4.2 naturally aspirated. The R has a different manifold but I`ve not yet heard of one of those decaying.

A good job we arn`t still driving the 4 litre V8. Those had plastic thermostat towers which would disintegrate. When you tried to unbolt the two parts, the threaded inserts would spin and you couldn`t release the bolts. The after-market produced an ali version which was much better!

Mike