So ive had the "Engine Coolant Low" warning on my dash for quite some time now.. it comes and goes but is on for the most part. i checked the coolant level, but it isnt low at all.. i was told that the sensor could possibly be the problem however when i went looking for the sensor at the dealer they said the sensor alone was not available. i need to buy the whole engine coolant reservoir. Can anybody shed some light on this subject? anything else i should check before purchasing a new reservoir??

 

You should maybe try pulling it and cleaning it. Maybe something got on it. I did hear that its sensitive and that maybe you are just a hair low it will trigger the sensor. I'm not sure what the resistance of the sensor is but you could always test that and see if its bad. If you find out that you do in fact need a sensor post up here and I'll make sure my old one still works and see how hard it would be to package without damaging and send it your way. I replaced my tank which comes with a new sensor and I still have my old one.

 

Sorry man but I guess I didn't keep the sensor cause I just tore apart my garage and I can't find it anywhere. I thought I had put in back in the tank but I only have the tank no sensor. I'm mad too cause I replaced another members overflow tank and threw his out cause it was cracked with the sensor in it. I kept my tank cause I may look into making one out of aluminum in the future but must of not even thought about the sensor and tossed it. I'm sure with all the tanks that have been replaced someone should have a sensor laying around for you. I would also just make sure your coolant is all the way to the full mark. You may be full cold but when it gets hot and circulates it drops it just enough to trigger the light.

 

Also be sure the electrical connector to the tank is clean and snug.

 

The sensor is kind of picky. Are you sure the coolant level is topped ALL the way up. You can't even see the part of the coolant missing needed to trip the sensor. Next step, pull the plug, jumper the two wires, does the warning in the dash go off? Finally between all of us who have replaced coolant tanks I'm sure someone has a busted tank with a good sensor in it. All it takes is 1/4 turn to pull it out. Take care, George

 

Also the overflow tank has chambers in it so you have to make sure its up at the full line cause if it isnt the chamber with the sensor may be a little lower then the chamber you see when you look down at the fill post.

 

Good stuff dudes.

 

I know this is an old post but you guys have been very helpful thanks. I have the same sensor problem and am all set to order a whole new tank and get it over with, but wanted to test the sensor as you suggested by jumpering it, but the light still does not go off? It stays on while unplugged too? is there anyone that can confirm that it goes off by closing the circuit(shorting the plug)? I would hate to get a new tank and it's another problem...

 

Another 2 ideas: measure the voltage at the sensor and also (disconnected from car wiring) the ohms of the sensor with & without it in the coolant. Sounds like the wiring/connection may be the problem.

 

Unplug the harness from the sensor.

Jumper the two pins in the harness with a paper clip.

Start your car. The warning should be gone.

Take care,

George

 

ok, note to self and others.... when working on your jag and you are testing to see if the red idiot light goes out, make sure you shut the hood!.
The low coolant sensor did go away when i jumped it but i had my daughter in the car looking at the red light to go off. well it wont go off until you shut the hood. ... turns out the sensor was fine , it was the float inside the chamber that you cant get to. so i stuck a small tube in thru the openings to the far chamber and shot some air in there while it had coolant in it. the bubbles seemed to jar the float loose and all is well.(ps. before shooting air in from my air gun close mouth, so i dont drink antifreez) the stuck float idea was from another post somewhere in here, you guys are great. In fact I would never have even considered buying a jag if it wasnt for finding this forum, thanks again...jag newbie

 

I know this is an old thread but I have a 2003 Jaguar S-Type. Basically, can someone please tell me which plastic tank is the engine coolant resevoir?

I keep getting the "Engine Coolant Low" but I need to verify it really isn't before I drive my car anywhere.

Thank you!

 

It is the white tank with a black plastic top front and center under the hood.

Most of the time if you have a warning, it is genuinely low. If you top it up, and it is low again after driving a while you have a leak somewhere that needs to be found.

For topping up just a few ounces, just one time, you can use distilled water. After that you should use a 50-50 mix of the correct coolant and distilled water.

 

Thank you. I just had my belt and water pump replaced two days ago and the light came back on the next day.

 

If it takes more than 12-16 ounces or so to refill it, you probably have a major leak and should towed it back to the shop to play it safe.

If it is just a few ounces to fill it, keep an eye on it, carry some extra water with you just in case it happens again after you refill it. You probably have a slow leak so you can drive it back to the shop.

If it never happens again after you refill it, you might have just had some air in the system that was eventially displaced.

 

Thank you again. Now, I love my Jag but yours is the one that still turns my head. Beautiful car!!

 

Thank you! We do love out S-type almost as miuch though!

 

It is probably just a bleeding issue... See, the coolant system needs to be bled of air when any service is done. Even when bled properly, you could still have bubbles in the system that will bleed out in a couple of days of use, triggering the "Check Coolant" message..

I got the same thing after a DCCV replacement. Freaked me out at first until I looked, and it was only a little down.. Added some coolant and all was fine.

 

Old post but just got my jag back from Fort Worth dealership where they "checked" and filled all fluids and light came on. Just as fast as it came on it went off. Will check reservoir in the morn. Good info. Thanks to all.

 

Hi I have 2003 S-type R my coolant light comes on after the runs and heats up? I have to release the air out of the reservoir through the cap and it goes off this happens every time I go on a trip can anyone help me with this? Thanks, James