I have an XK8 2000 with a "Low Coolant" warning and a full reservoir. I went looking for the coolant sensor and found this device loose near the reservoir. The rod that must be a sensor is broken and it must plug into something, but I am lost. Anybody know what it is?

Loose near the coolant reservoir.

 

It is the coolant sensor, and it fits into the reservoir from below - you can't see where it goes from above. Have a look at this for images from below: https://www.ebay.co.uk/itm/253182800490

I'd get yourself a new reservoir.

 

I've "borrowed" the photo from the ebay link you gave. The listing will soon disappear but the photo will always be useful for Coolant Level Sensor questions..





I'd never thought to take one when changing a tank.

Graham

 

I had the "Low Coolant" warning after collecting the car from a garage, (after having some work done to the car for the M.O.T)
When i got back home, and looked under the hood/bonnet to investigate...
I found this sensor hanging down, just under the reservoir.

After re fitting ( need to push it hard till you hear it click in place ) no more low coolant warning...(over two years and still ok)

Any owners getting the low coolant warning, with a full reservoir,
This is a good first check to make sure the sensor has not become detached.

 

Thank you all for the quick replies. I found a replacement sensor on ebay for under $30, so if all this works, it will have my record for the least expensive repair yet. It looks like I will have to do some work to get to the underside of the reservoir, but that usually costs only some skin and a little blood.

 

You might be able to feel around and get the sensor in. It snaps into place in the bottom of the reservoir - it has to be pointed in the right direction(photo above). I've had mine in and out a bunch
of times. I've found it's easier to pop the sensor in and out than to remove the electrical connector.

 

Thanks Jimmy. The photo didn’t appear, but I think I see the direction in the parts diagram.

 

Oh, I meant the photo in post #3 above that GGG so generously provided. It shows how the sensor is oriented and it fits in between two "shoulders" molded into the bottom of the tank.
But you get the picture - you know what I mean !

 

I received my new sensor and attached the plug. Using fingers of both hands, I was able to get the sensor into the hole, and even to get it into, or close to the correct position. No matter how hard I pushed, even with little clicks, could I get it to lock in place. My fingers aren't all that strong anymore, so that may be the issue, embarrassing as it may be. I thought about taking the reservoir out to turn it over, but I can't reach the bolts attaching the bracket to the frame, nor can I figure out how to detach the reservoir from the bracket, the one with two bolts. Now, just to justify my attempting this minor repair, I have in the past replaced both door locks in this jewel of a car ( my wife's car), and the main computer that I accidently shorted fixing the lights in her visor mirror. Any further advice will be appreciated.

 

Hi Harry,

I may be thinking of the X350, which was the most recent vehicle on which I had to fool with the coolant sensor, but my recollection is that the sensor has to be twisted 90 degrees in order to lock it into place in the bottom of the reservoir. So you might try inserting it with the connector 90 degrees from the orientation shown in Graham's photo, then carefully twisting it to that position. Apologies if the X100 sensor doesn't work that way but it's worth a try.

Cheers,

Don

 

Thank you Don. I went out to the garage immediately upon receiving your suggestion. I found that it was impossible to turn the sensor 90 degrees with the plug attached. I know that if I unplug the sensor, I will never be able to get that plug back in and locked with the reservoir still bolted in. I’m thinking of the black tape fix I used on the engine warning light.

 

Jimmy, I have tried to push the new sensor into the hole in the reservoir with my fingers but cannot. I even got a much younger friend to try, but he was unsuccessful too. My only option now is to turn the reservoir over to see what is going on. The mystery for me are the two fasteners side by side on the bracket attached to the body. I can't figure out what they are. I took a picture with my phone, but it didn't tell me much. I have it attached. Can you help?

My mystery fastener...

 

Harry,

See my photo of the bottom of the tank in post #3. The sensor should slide in quite easily and then click into place between the two "shoulders" on the tank without too much pressure.

Difficult to be certain from such a close up but I think that's the tank locating grommet in your photo (arrowed in red below):



If so, you are trying to insert the sensor in the bracket instead of the tank.

Graham

 

There are two large "locating pins" on the side of the tank that slide into holes with grommets in them. They are shown in the bottom left of the photo in post #3 above. Once you get the hoses
disconnected and the torx screws out, the locators on the tank slide out of the holes. The hardest part for me was getting the larger hose off at the bottom of the tank. If you take everything else off you can move the tank around to get to the clamp. But, you really shouldn't need to remove the tank to put the sensor in. If it's oriented correctly, it should "snap" in.

 

Thanks again for the help. What I thought were fasteners were those rubber grommets that the two pins slide into. Once you pointed that out, I was able to move the tank sufficiently to actually see the bottom of the tank without removing the hose clamps. It gave me some leverage to get it in there. No click but it seems secure and the low coolant light is OUT. I've learned more than I ever wanted to know about this car...