I've been getting a "Coolant level low" message from time to time. (Never got this in the first 1-2 months I owned the car). Sometimes it goes away on it's own and sometimes I just break down and add some coolant to the reservoir, which makes it go away. It never seems low though, as it always seems to be at "low fill level" line and when I take off the cap, the coolant is at the plastic that says "max".

The other strange thing is that I sometimes smell what I think to be a sweet coolant smell while driving, though it is very subtle and might just be the plastics, leather, and engine compartment odors mixing and coming in. Are there any common coolant leaks on '09 Supercharges?

Regardless, why would the coolant show as being low when it never LOOKS low. Am I just reading it wrong?

EDIT: This issue is fixed. I first replaced the coolant level sensor but this didn't fix the issue. I then tested the "float" in the coolant reservoir and found out that it doesn't float anymore (got a hole in it I guess?). I bought a replacement tank and and after replacing the old tank the error is gone for good.

Also, I noticed that with the old tank, while the coolant level in the coolant fill indicator tube looked okay, the other areas of the tank were much too full (the looked overfull everywhere except in the fill tube) and this most likely caused the coolant smell due to overflow. With the new tank, the coolant level is shown to be the same throughout the whole tank, and not just in the area of the coolant fill indicator.

 

If you overfill the coolant tank it will eject the excess when the engine gets hot. Hence the smell.

If a visual check shows the coolant level between Min and Max then you have a fault in the coolant level sender. Never overfill a cooling system or a sump. More is not better.

Get the fault checked.

 

When you say you put coolant in there, when do you check it?
Best time to check the coolant is when the car is cold and hasn't been driven in 6 hours.....or you can check early morning before you start it. Otherwise, the reservoir will give you a wrong reading

 

+1 to both the above.

The ONLY time to check coolant is when the engine is COLD. Apart from anything else, it's a safety thing.

As jagular explains, make sure you aren't overfilling or the excess will vent from the overflow.

If you aren't overfilling and are in fact losing coolant, are you turning the Coolant Reservoir Cap until it clicks? If not, with the engine up to temperature, coolant under pressure could be forced past the seal. It's not unknown for Reservoir Caps to need replacing just as Jaguar coolant level sensors aren't the most reliable components.

From the regular small loss and the fact you are fairly certain you can smell coolant whilst driving, you may have a slight leak from a hose or hose clip. The best way to troubleshoot this is to have the cooling system pressure tested. This is done with the engine cold and the equipment is attached in place of the filler cap. The system is then pressurised and examined for drop in pressure and leaks.

You're right to be concerned if you do have coolant loss and need to investigate it before anything more serious develops. All Jaguars are very sensitive to overheating.

Graham

 

I'm not sure how smart the sensor is but on some cars if you park on a hill the light will go on because the coolant sloshes out of the way of the sensor. The light would go out when the car was on level ground again. This could be the case in your situation. I'm not sure on the smell if you don't appear to be losing fluid. I've never seen anyone post about this issue.

 

Thanks guys. Yes, I can confirm that I only open the reservoir cap and check the level when the engine is good and cold. I do make sure to tighten the cap to a click or two, and when opening the cap, pressure is released. I am unsure about the location of the overflow, which I would like to inspect. Also, if the coolant level sensor is bad (which I suspect), is it on the bottom of the reservoir where the sensor wire is attached? If this doesn't lead anywhere, I'll give the pressure test a try.

 

The coolant level sensor clips into the base of the expansion tank. Item 3 in the following graphic from the Parts Manual:

JAGUAR XF Supercharged - Coolant Level Sensor.pdf

If it's a similar design to the XJ and XK models, it'll be a small magnetic float. Owners of these other models have frequent issues with the level sensors

Graham

 

The cooling system should not be under pressure when stone cold. There should be no "pressure release" when the cap comes off. Neither should there be any vacuum. The expansion tank cap holds pressure in as the system heats up but has a pre-set maximum pressure above which it blows out excess coolant. It also has a vacuum preventing air vent which opens below atmospheric to allow air pressure to match ambient pressure. If either function does not work replace the cap.

One source of mysterious loss of coolant is head gasket leak ( incipient or complete failure) allowing combustion gas to pass into the coolant jacket. Obviously you will want to track down this fault correctly as one possible fault requires only a minor repair and the other can get bad enough to require a new engine!

 

Thank you both, that .pdf is especially helpful. I'll check again then first thing in the morning and see if I have pressure or not in the system. If the cap is fine, I'll order a new sensor and change it out.

Edit: just realized the diagram doesn't have a part number (sensor, callout #3). Any info on that if I end up having to order one? I'd really hate to have to order another complete reservoir just for this.

 

Here's the matching Item numbers and Part Numbers to the PDF posted earlier in #7:

JAGUAR XF Supercharged - Coolant Level Sensor 2.pdf

Jaguar frequently supersedes part numbers with a change of design, specification or supplier but dealers are able to trace any changes to identify the current number.

Graham

 

Update: bought a new sensor and changed it out. I noted that there has been no coolant loss at all, the reservoir was completely full. The coolant level is on the "high" mark of cold fill line. Also checked the cap and when the car is completely cold, it doesn't release any pressure, so it seems to be operating correctly.

Light went off initially while driving but the "coolant level low" warning comes up still everytime the car gets warmed up, after about 5 minutes of driving.

Seems to me that whatever the coolant sensor is checking against is bad. Is there something in the reservoir that it measures? When I take the cap off and look down into the reservoir, I see a black ring at the bottom (this sits over the area with the sensor). Is that black ring supposed to float or does it send some kind of signal to the sensor?

Any insight as to how this sensor works might help me find the issue, please help!

 

So, after poking the white float ring, I've discovered that it doesn't float. If I push it down, it just stays at the bottom. Is there a way to replace the float or am I going to have to buy a whole new tank? Can you post the part number for the tank as well?

And I have a brand new sensor that I now don't need if someone wants to buy it cheap.

 

Here's the Part Manual section for the Expansion Tank:

JAGUAR XF Supercharged - Expansion Tank.pdf

Part numbers are frequently superseded when there's a change of supplier or spec but Jaguar Dealers can always trace current number from the superseded one.

If I crunch the numbers for Time v Cost, I'd just go for the new tank after already trying a sender without success.

Graham

 

You might want to try searching Car-Part.com--Used Auto Parts Market for a used one if the tank is spendy.

 

Thanks guys, I'm on the hunt.

Thanks for the pdf. I have a fairly early VIN, in the 14xxx range. Same P/N for the tank in that range?

 

Blaydes - Looks like you've already got there but replacing the expansion tank is probably the way to go. I had the same problem and per my dealer, dirt in the reservoir was causing the fluid level sensor to stick at the bottom. They R/R the whole tank.

 

EDIT: This issue is fixed. I first replaced the coolant level sensor but this didn't fix the issue. I then tested the "float" in the coolant reservoir and found out that it doesn't float anymore (got a hole in it I guess?). I bought a replacement tank and and after replacing the old tank the error is gone for good.

Also, I noticed that with the old tank, while the coolant level in the coolant fill indicator tube looked okay, the other areas of the tank were much too full (the looked overfull everywhere except in the fill tube) and this most likely caused the coolant smell due to overflow. With the new tank, the coolant level is shown to be the same throughout the whole tank, and not just in the area of the coolant fill indicator.

(add this to first post as well)

 

reason why coolant level low warning was coming on my 2009 jaguar XF I Took the vehicle in for service for a hose leak they replace the hose but apparently put the wrong radiator fluid in it or mixed water with the original. the warring light came on so they sold me a sensor for $34 but it didn't fix the problem. next they wanted me to pay 219 for the new reservoir, but it did not make sense to me that it was working before I took it in. I asked about the coolant being different and their response was no way it's the same. so this is the test I did and found out if you mix water with the coolant the float in the tank will not float
i showed this to the jag dealership and other Mechanic and the could believe it


hope this helps

 

I also had the low coolant light keep coming on.
I changed the coolant container which holds the coolant, but it did not solve the warning light problem.
I watched the video about making sure the mix of coolant to water is correct, and I drained some of the fluid, then put in a richer mix of coolant to water, and then the warning light when off!
Thank you esaws7474 for your video, you solved my problem.