Mornin' brainy folks,

My XJR started showing the low coolant warning yesterday, randomly as I drove it'd come up & go away again.

I've not done the obvious & checked the coolant level yet, but as I recall there's a connector or something under the header tank that can cause this to appear too? So I'm asking in advance of looking at the car tomorrow so I know what to check when I find the coolant level at the correct level as I expect too.

 

I had at one time on an older broke computer all the connectors in a catalogue in PDF form for the X308 if someone can post it again

For now , he needs the proper coolant level servicing procedure

I do not have the V - 8

 

The coolant system ? - Jaguar Forums - Jaguar Enthusiasts Forum

And if this is correct ?

New Jaguar XJ8 XK8 XKR XJ X308 Engine Coolant Level Sensor LNA5740AB | eBay

 

In England if correct

Coolant Sensor, Sensor Water Level LNA5740AB Fits for Jaguar | eBay

 

Level sensor ring in the expansion tank may be stuck and does not move or has bee filled with coolant and sinks to the bottom. If you do not need the level information. Just jump the sensor over at the connector with a wire and the text will never show up.

 

Thanks for the info chaps. Turned out the coolant was low, so I've topped it up by a couple of inch, I'll keep an eye on it but it's never needed topping up in the four years or so since I flushed the cooling system so I'm not expecting issues.

 

Hoses can certainly start leaking. One time could be a fluke...2 times means start investigating

 

Yep...I'm with Quad...It did not become low without a leak somewhere.

 

Indeed. I'll keep an eye on it, but there's no puddles underneath or anything. It doesn't feel serious to me, if that makes sense.

 

I just had this issue with one of my sedans.
I smelled a faint coolant odor and the level seemed OK.

A few weeks later I got the 'low coolant' message.

Pressure test revealed a 'pinhole' in the coolant reservoir.
No puddle under the car but I did see stains on the engine and gearbox.
Stole one off one of my parts cars and everything is happy again.

 

Well to update this thread, it did it again yesterday so it is leaking.

With it topped up & running I could see the occasional drip underneath, roughly level with the back of the front wheels & in the centre of the car, around the lower cat to exhaust connections. I couldn't see where it was coming from though as everything looked dry up top & behind the engine. I didn't get a brilliant look as it was getting dark, so I'll have to jack it up at the weekend & try again if it's dry outside.

I know it's been covered a million times, but just hoping for a quick list of the sort of areas prone to causing leaks around the back of these lumps.

Also, when searching round last night, when looking down the gap between the supercharger & the inlet manifold, near the front of the engine on the right side there appeared to be a pipe or something the colour of an old leaf, which seemed wrong to me. Is that anything to worry about? or just my mistake as you can see so little down that gap?

 

Follow motorcarman's advice above. Get a pressure tester on it and be aware your car is now 24+ years old? ALL the rubber hoses and plastic parts are severely decayed at this point. So when you do find the leak consider replacing all the coolant hoses. It's not unusual for an old car to spring one leak. You then fix that and now you have disturbed the engine and caused another coolant leak. Then you play this game until you replace the several dozen hoses that your XJR has.

I had a 2005 STR that car is similar to yours and I had 23 separate cooling hoses to replace! That's NOT including the upper radiator tank and water pump which are both additional cooling failures. This would also be an excellent time to replace the thermostat and change the coolant out since it's all apart.

Finally don't count out the radiator itself. They can and do fail because of age.
.
.
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Common leak areas are the FEED and RETURN hoses under the intake and the HEATER HOSE ASSY. above the gearbox.

 

Thanks those are the famous ones in the Vee & the octopus right?, I couldn't see anything wet around those when I was looking and the top of the gearbox seemed dry. But it has to be coming from somewhere so I'll have a better look at the weekend.

It's booked in at a specialist next month for front spring pans anyway as I hate playing with car springs. Way too much energy trapped there if it goes wrong. So if I can't find owt, I'll park it up till I take it there & get them to do it as well. It's been a while since it's attacked my credit cards so it's probably due something expensive.

 

Having just spent ten months chasing coolant leaks (mine presented at the bell housing of the transmission, mainly), it is simpler to just replace all of the hoses at once. You will end up doing that anyway. I ended up having the SC off twice, on my XJR. Complete nightmare. Even if they haven’t all failed, it seems like the second one is replaced, another goes. I wish I’d have done all of them initially, would’ve saved me from a lot of “there’s no way this is worth it” moments.

 

Yeah that's a good point.
If it's dry at the weekend, I'll see what I find & how the hoses look in the difficult to access places.

 

Well I took the afternoon off work as the weekend is due lots of rain.

Got the car in the air & ran it to temp for half an hour, not one single drip. Which really doesn't help as it's emptied the expansion bottle twice in a month or so, so it's leaking somewhere. I'll get the garage to pressure test it, they are a Jag specialist so will know where to look. I'm betting it's something expensive like valley hoses, nothing cheap happens for me with this car.

in other news as I jacked it up the NSF jacking point moved up without the car as the floor tore. Wonderful! I had that corner welded about four years ago too, so obviously a bit they missed or was ok then. It's now booked in for that in a week or so, I've asked them to look at the other side too as that made some nasty noises even though it took the weight.

This is obviously all due to me saying to someone the other week that it's done really well at just being a car this year & hasn't needed anything....

 

I am running into this with my car. I just ordered some UV dye to add to the coolant. Planing on adding it when I add coolant and then run it until it says low again and see if i can find any traces of the dye to see where it might be going.

Hoping it is a hose somewhere and not a air to water cooler

 

"Hoping it is a hose somewhere and not an air to water cooler." What does that mean?

 

XJR has an air to water intercooler that appears to have a history of developing leaks which means the coolant will be injested into the engine