Hello hopefully someone can help me
I keep getting the engine coolant low light
It stays on then turns off then back on
I have just replaced the coolant sensor
But it has made no difference
Thanks
Darrol

 

Hi Darrol,

What year is your car? Guessing by your username, is it a 2004?

The reason I ask is the 2003+ reservoir is different than the early models. This thread has a lively discussion about a similar problem on a 2003:


https://www.jaguarforums.com/forum/s...sensor-216006/


That thread hasn't been totally resolved yet, but it appears there's a magnetic float that actuates a reed switch for the indication. At the moment, the switch itself is probably okay but the float seems to be stuck.

Perhaps your float is binding on occasion? That might explain the intermittent nature.

You can test the reed switch separately. Remove it from the vehicle and set up an ohmmeter to read continuity between the two contacts. See the pics in the other thread. The reed switch is the skinny glass capsule inside the black sleeve. Place a magnet near the reed switch and you should have continuity. Remove the magnet and the contacts should open.

Do you have a part number for the switch you replaced? Per Jaguar, the switch is only sold as part of the reservoir assembly ($$$). I think I have found a Range Rover part number that should fit a late model S-Type (not sure about early model) but it would be great to hear from somebody that has a confirmed fit.

 

Would be great if you have found a Land Rover part to fit kr98664!
Darrol have you thoroughly checked all the hoses for any water leaks? Some could be old and soft by now? Not always easy to see a leak.

 

From post #15 in the thread linked above:


"Check this out:

https://www.rockauto.com/en/catalog/...el+sensor,2184

It's for a 2004 Range Rover.

OEM #PCJ500020

Standard Motor Products #FLS169"


---------------------------------------------------------


Unfortunately, I don't know if it fits. It looks very close, but we need a guinea pig to be sure. The aftermarket version is under $10, so if I needed one, I'd take the gamble. Sure would be a lot cheaper than having to replace the entire reservoir.

 

Hi thanks
Yes my car is a 2004 4.2 v8
6 speed automatic
I purchased this car 6 weeks ago
The old owner said he had a new expansion tank put in and just after that he had the coolant low light come on as well
He said he got used to it
Car dose not use or leak any water
But I noticed tonight when engine is running
There is a gap between top of expansion tank where there is no coolant
Then when engine is off expansion tank fills up again
Thanks
Darrol

 

I had a similar issue, however, mine was caused by a corroded connector further up the wiring (https://www.jaguarforums.com/forum/s...sensor-215072/). Does the low coolant light go away when you shunt the connector that plugs into the coolant sensor? If it stays on then it might be a wiring problem upstream (this seems to be rather rare and mine is probably the only case I have found on these forums. Worth a shot. More than likely though, you are looking at a bad sensor in the expansion tank. If that is the case, I have a spare tank w/sensor for sale (my old one which was unnecessarily replaced before the wiring issue was found). Feel free to send me a PM.

 

Hmm, the problem started with the new tank. Any idea why it was replaced? How about this scenario?:

Old tank was cracked and leaking, a common problem. Even if the leak at the tank had been very small, the cooling system could not build up full pressure, but you wouldn't know. The new tank fixed that leak, and let pressure start building up to normal levels. Meanwhile, you've got a previously unknown second leak somewhere, but it was never apparent when the system pressure couldn't build up because of the first leak at the old tank. Also, and this is VERY important, if the leakage spot is physically high, you won't necessarily get coolant spraying out, possibly just air. Trust me, I've learned this one the hard way. So my TheoryDuJour™ is you've still got a small undiscovered leak in the system. Pressure can't build up to normal, and because of that you've still got air in the system that hasn't worked its way out properly. Under certain conditions, the coolant level at the reservoir drops and the indication correctly tells you so. There may not be anything wrong with the indication system.

Pretty good, huh?

Can you get the low coolant message to appear while parked, and then physically check to see if it is accurate?

A long shot? I don't know, but quick and easy to rule out by running a pressure test of the cooling system. If you don't have a pressure tester, some auto parts stores (Autozone, for example) will loan them for free. Pump up the system and if the pressure decays, even if you don't see any coolant escaping, you've still got a leak. Don't forget to test the cap, as if it vents early, it will let pressure escape but you won't always see coolant loss. Make sure the mating surface at the tank neck is smooth and clean so the cap can seal properly.

 

As you'll read, the switch does respond to a floating magnet inside the tank. float is high = no alert. Float is low - dash alert. You should be able to hear it if you shake the tank. RockAuto.com has a great price on a replacement tank and sensor for around $30..
good luck.
Bob

 

I had the same problem, it turned out to be a blown head gasket. Was not fun!! I hope this is not the case for your car.