Hi Fellow Jaguarians,

I have been using my Jaguar for couple of months and it was running good without any issues or concerns, but couple of days back I saw an error message in the message center as "Engine Coolant Low" which was displayed for couple of minutes when I started the car in the morning. When I gone through the manual it is mentioned that whenever my engine gets overheated, this message will be displayed. But the irony is, it is displayed when I started the car in my morning which was left untouched for the whole night. I also noted that once if the message is disappeared then it will not be displayed throughout the day until I start the car on the next day morning.

Thanks!

 

Check your manual for where coolant reservoir is under the hood and check the antifreeze level in it, then report back.

 

Try this first and let us know.

 

It means you risk overheating (and then serious engine damage).

If you have enough coolant, next suspect is sensor/wiring.

Do not add the wrong coolant!!

 

Believe me the system does not lie ! I had this some months ago, and found that I had a very small leak in a connection to the fuel rail at the back of the radiator. The technician advised me to leave the car with the shop, as the connection could let go at any time leaving me with no coolant and a damaged engine. Cheaper to leave the car and take the bus home !

Anyway, both leaks found, (yes, more than one, with another one found on the header tank), and fixed with new water rail and header tank. Not cheap, but cheaper than a new engine !!

Reason the message disappears when the engine is hot is because the coolant expands thus bringing the coolant back to above the level detector. My message appeared like yours when the engine was cold, and disappeared when hot.

 

Is probably a leak, and hence low. I would suspect the small hose attachment on the header tank where the hose connects. This rots away and leaks. Just changed one this week on friends xj8l. About 1 hr. Tank itself is about $120. Seems to me that something rots plastic.

Might not be this either, but find it what ever it is, if it is a leak, no good could come. Good luck.

 

The small hose connection to the header tank starts cracking and allows very small amounts off coolant out, that eventually triggers the low coolant alarm. The cracking continues until eventually the hose will just drop off the tank but most people will have spotted the leak before that happens. I don't think the plastic rots, it is just a bad design, and vibration causes it.

 

On mine i had to replace the overflow coolant tank. small leak near hose connection. Complete bullshit about this warning meaning your running hot. there is a magnetic floater piece that easily gets stuck inside the overflow tank itself. Even mine after a brand new reservoir had the message.

Im a MECP Master Tech specializing in auto electrical
This is what I did. On the bottom of the reservoir there is a electrical connector with two wires. disconnect it. Get a paper clip or piece of wire and complete the loop. ie put the wires together. Boom no more bullshit message. Now just pay attention to that temp gauge when driving. Every now and then pop the hood and check level of coolant. The message will never come back for the life of the car! i promise!! enjoy!

Ive also bypass many other stupid sensors for many cars.

 

Of course with that bypass if it loses coolant it'll wreck the engine with no warning.

So glad I'm not in Las Vegas.

 

I only recommend this if you monitor the coolant level and temp like i do every other day. if you are not handy and dont want to worry about it then replace all that needs to be. jagv8 so im an idiot? i know what im capable of doing and have helped thousands of people in my life. My jag runs perfect by the way. and i modified every thing on her. The main engine temp gauge is all you need. when that needle is rising any idiot will pull over and check. even if all coolant leaks out of overflow reservoir there is plenty of coolant flowing to the engine and the engine temp will remain normal for 20-30 miles.

 

Evan, I don't see anywhere where JagV8 called you an "idiot" as you put it. How you choose to maintain/repair your own car is entirely up to you. But it boggles my mind why someone would suggest to others that they should bypass a coolant level sensor rather than fixing the problem properly by replacing the rather inexpensive and easily obtained tank/sensor. As I'm sure you're aware the temp gauge is computer managed, and by the time the computer decides to swing the gauge up/down from mid-point, you have mere moments to shutdown the engine before you are replacing a very expensive engine. You'd have a whole lot more warning and much less risk if you could have been warned that the coolant level was low. I wouldn't be so worried about all the coolant leaking out of the overflow tank, so much as there is a leak elsewhere that draws all the coolant out of the tank while the engine is running, at which point the system is likely got a bunch of air pockets that can destroy an engine very quickly - and in your situation, without any warning.

 

To the OP Sasie,

Coolant leaks are common on the XJ8. Ours has multiples, including possibly the AUX electric coolant pump. As the gang has said, first thing to check is the main coolant overflow tank, right up front and center when you open the hood. The small diameter hose connects to the tank in a little recessed area, and those are poorly designed to break "when" not "if." I found a replacement on Amazon.

This is an example, please verify your model before ordering. The price is only $40 because it reuses the sensor you already have:


Open the lid on your overflow tank and you'll see some stair-stepped blocks inside that indicate where FULL is. Is your Jag overheating or not? The low coolant sensor will come on as soon as the overflow tank dips below minimum full, but your TEMP gauge will tell you if the car is getting hot. Keep the tank full until you can get this resolved, but no need to panic.

Even after replacing our tank, a new leak has cropped up, so be prepared to chase all the leaks until you get it all sealed up again.

 

Hi Guys, My apologies for the delay in response.

I did checked that coolant level in the reservoir and found that the coolant level below the minimum level, now I'm in need of your advice about the coolant I need to use.

Thanks in advance!

 

For a small leak and hence not much coolant lost, you can top-up with a bit of water; this just gets the low coolant message off the display, but obviously doesn't deal with the leak !

So you need to investigate where the coolant loss is occurring. As others have said, the header tank is a common leak area, where the small pipe connects at top-rear. Other places can be the thermostat housing, and if its a supercharged car, a small hose that runs in the V if the engine underneath the supercharger, (an expensive fix because of the labour involved in dismantling to get at the hose).

One trick I learnt when looking for small leaks is to do it after dark with a torch. This is because during the day, your eyes are adjusted to daylight so you don't spot the small globules of coolant, but at night with the torch, they will sparkle like stars in the sky.

 

Dex-Cool Extended Life Coolant type 50/50 coolant/distilled water mix will suffice. Orange in color not green like most on shelf. Topping it off with just distilled water will work. Keep an eye on it once topped off. If level keeps lowering then you need to find out where it is going from.

 

This is incredibly bad advice.

There are plenty of reports on this (and just about any car site) of owners low coolant lights which then led to overheating. There's also a significant number of events of owners who ignored this and the subsequent overheat warning which lead to engine failure.

I'd bet 99% of owners do not now, and have no intention, of opening the hood every day to check fluid levels.

The probability of the switch failing vs. an actual warning is remote.

Fix the root problem, not mask the symptoms.

 

You are all right. I should have not done this to my car. now my engine is completely ****ed! lol I thought I was cool Sorry

 

lol, luckily my sensor is fine, but it's also the only car I've owned with a coolant level sensor. I wouldn't be concerned about losing the feature to bypass a false warning.

If it's worth mentioning to anyone I'm MECP Advanced certified and if it's one thing that seems to intimidate even the best mechanics its luxury car electrics. To be honest compared to Mercedes and BMW, Jaguar's systems are fairly primitive in the sense that many are easy to bypass by just unplugging modules and doing a power reset disconnecting the battery. It really doesn't surprise me that the coolant level sensor circuit is just looking for a complete circuit.

 

Torrid nailed it! Just a Sensor looking for a complete circuit. Exactly like an airbag sensor or seat belt sensor. Airbag sensor looks for a complete circuit Through a resistor value.

It really does take a person with somewhat electrical knowledge to know where im getting at. And yes this is also my first Jaguar with a coolant level sensor. ( Ive owned 3) And never overheated. Completely poor design on overflow tank with floater sensor. Bought tank brand new a few times. If the sensor is giving the computer false information from time to time I would pop the hood and check because I cant trust that false info anyways

alright next subject

 

Guess you haven't worked on too many new(er) or high end cars then. Pretty much standard equipment. Given the common knowledge of what can happen to engines that are low on coolant, I'm surprised that not all cars have them.

Missing word was 'misguided'?