Hi all,

More advice sought with my 2005 XKR (XK100) convertible please.

Over the last few months I have started getting an intermittent low coolant light, but no leaks, normal level in tank, normal pressure test. It would often reset if I did not drive the car for a few days, but nearly always come on approximately 10-15 miles into a journey and stay on. Roughly around the same time I started getting an intermittent suspension fault light which would come on and then go off after a few minutes, this could happen at any time, even when in traffic and just crawling. The car drove fine. I took it to an indie specialist, pressure test was normal and he thought it was most likely the float becoming porous and sinking, so replaced the expansion tank along with spark plugs and ignition coils as there was a slight misfire. He couldn't find a code for the suspension fault but thought it was the shocks.

However I am still getting the low coolant light and the suspension fault light (intermittently), I took it back to the indie who bridged the coolant sensor but the low coolant warning light did not go off. He has suggested it could well be a wiring issue.

Prior to these lights coming on I did get the instrument cluster repaired as the speedo needle had stopped moving, he has suggested it could well be a connection at the back of the instrument cluster which is resulting in an open circuit. HE has suggested checking the wiring from the front of the car to the cluster, which would be several hours of labour work.

Seeing these lights is extremely annoying, and I do not want to keep throwing money at the car and still not being able to solve the problem.

I would be grateful for thoughts on what the issue could be.

 

According to the electrical diagram (check jagrepair.com for a copy, 2003), the coolant level switch does go straight to the instrument cluster. It seems the float has already been tested. Now, the next step is to remove the cluster and check the status of the coolant level pin at the IC. Removing the IC is pretty straightforward. A number of us have done that before to replace failed bulbs, an hour job tops. With the status of the pin reflecting the status of the switch (or not) you should be able to determine whether the wiring or the cluster needs work.

PS: FWIW, it is not uncommon for either of the 2 big connectors to the IC to somehow not engage perfectly after removal/reinstallation (there are lots of wires in a bundle and a lever involved). I would double check that first. Double check for bent pins, or even if you need to bend the coolant switch pin ever so slightly to make better contact. Best with the battery disconnected for this job.

Best of luck, keep us posted.

 

Joining the level sensor wires should bring the warning light ON . Removing the sensor and turing it upside down should turn the light OFF. Are you sure you got the coolant level in the tank right up to the bottom of the threads?

 

Interesting - on my 1996 bridging the pins of the coolant sensor wire stops the dashboard low coolant warning appearing whereas an open circuit makes the low coolant message appear. On my car that is a fail safe in case open circuit occurs. I had to test it once when my level reed switch failed and I couldn't get another for a week or so - I bridged the pins to stop seeing the message constantly!

 

Hi All,
Just a quick update, due to work I was unable to look at the car, so I disconnected the battery and just let it sit for the last few weeks. Today I started the car, and no warning lights, opened the expansion tank, and saw the coolant was right on the neck line, as the car warmed up it dropped by 1-2cm, so I topped up with water. I drove the car for 45 mins and thankfully no low coolant light. So fingers crossed my problem is sorted. However it still does not explain why bridging the sensor did not turn off the low coolant light initially, perhaps a hard rest is needed hence disconnecting the battery seems to have done the job.
I will still keep an eye on the coolant level and also the temp gauge as I am not convinced the problem is sorted.
My suspension fault light still comes on intermittently, even at standstill but I am less worried about this.
Will keep you posted but happy to read any thoughts.

 

I kept getting a low coolant light even though I had checked everything. Turned out there was a very tiny leak on an O-ring at the bottom of the radiator. Fixed that and never had a leak or sensor go off since. Often the most simple of things.

 

Important to check the overflow tank behind the plastic on the RH front wheel arch if its not half full you will continuously get the level dropping in your expansion tank as it pumps to the tank but does not get sucked back.

 

Hi, a delayed update, but the issues ended up being a loose connection behind the instrument cluster! I had work done on the cluster and the garage didn't connect it properly. All sorted now, just need to fix the aerial, fix the sat nav, re-allign rear springs, new ABS sensor, rear break light, clean my headliner.....