So my 2009 xk developed a leak in the coolant reservoir, specifically on the bleed screw. I ordered a new one and when I was swapping them out I noticed that my old one did not have a coolant level sensor installed. The new reservoir came with one but I don’t even see my connector/wiring harness for the sensor. I looked all through the wiring diagrams and it does not show one, but the repair manual does state that the coolant tank has a level sensor on it. The other strange thing is I don’t have a ETC for a missing sensor. And the other day when I first noticed my temp creeping up on me, my coolant level was low and I didn’t even stop to think about why my level sensor did not warn me. Any ideas? These cars do have coolant level sensors right?
Makes me wonder if I tucked the harness away when I did the engine swap because I didn’t find a place to plug it in. Still I would imagine that I would get a trouble code for a missing sensor.

 

I think only the 5.0L cars have the sensor.

 

That’s correct, the first gen X150 does not have that sensor and the replacement tanks are one size fits all. The tanks are still functional without it.

 

Yup, and now you have a brand new level sensor you can pawn off to the 5.0 guys

 

these coolant jugs must all be made by the same company; I had a 2015 VW CC with a leak & called the dealer to get one(100 miles away), but he said it is under warranty so bring it when you can, which I did.....Turned out OK, as they had to remove the front bumper to install the new one....

Armand

 

Thanks for the replies! I just wanted to make sure I wasn’t missing something. I just recently read up on that thread were a member set up an mcu and screen in the ashtray to monitor coolant temperature and other parameters. I’m betting some code can be added and that sensor can be wired up to monitor coolant level on 07-09 years.

 

yes but to what end? The OBD II port already feeds that data. You would need to add a gauge. It's been discussed here before. What would the concept look like please?

 

How would that data be on the canbus when there is no sensor in the first place? I’m referring to my model that does not come with a level sensor from the factory. I would have to research the sensor to see how it monitors the level, but I would imagine it makes continuity between two conductors, and completes the circuit. When the circuit is broken, the low coolant level warning comes on.
if that is in fact how that specific sensor works, the code for the mcu would be pretty simple. Pseudo code= if (no continuity)
warning = “low coolant level”
else; no warning message
The mcu has multiple GPIOs and one can be used for that sensor. Then the info is displayed on the screen. No need to go through OBD.

 

Vince, You are correct. A loose pin in a connector (open) caused a false "low coolant level" on my 5.0L.
Looks like a great upgrade for the 2007-09 guys to add the low coolant sensor.

 

Now I have received my new coolant tank that has the sensor fitted I am going to fit an alarm.

To acheive this I need to pass a small twin cable through the firewall into the cabin.

I have poked around and it is very compact (not easily accessable) at the rear of the engine compartment behind the Coolant expansion tank.
Has anyone done this before? Is there an easy way?
There must be someone who has done this- any advice please.

 

I have (and others) managed to run wire along side the big harness on the other side of the engine compartment (I haven’t looked at the expansion tank side).
There’s a big grommet that the harness goes through. Need the take off the electrical tape sealing the harness to the grommet, on both sides of the firewall. Then used a tool, which I found online (google ‘wire insertion tool’), which is basically a metal tube, and pushed it through the grommet beside the harness (I think some have poked a hole through the grommet itself), then fed the wire through the tube, and finally pulled the tube back out, leaving the wire in place. (The tube gets clogged with a sticky sealant as you push through, so need to unclog it before passing the wire through (used an appropriately sized screwdriver to push out the clog).)

 

Hi, I have a 2006 XK 4.2 that was not fitted with a level sensor from new.
I recently had a lucky escape when the valley pipe burst while driving, there were no warning messages or lights on th dash.
I only noticed something was wrong because the cooling fans came on even though it was a very cold day.
I would like to fit a warning device as you have, it would be a massive help if you could write a descripion of what you used and how you did it.
Regards, Dave.

 

Sorry, my description was for passing wires through the firewall. I don’t have a coolant level sensor, the wires were for an HKS extension module that connects to my HKS Camp2 in the passenger compartment. I have an oil pressure sensor and oil temperature sensor connected to that extension module in the engine compartment. Never investigated a coolant level sensor. (The HKS Camp2 picks up coolant temperature from the OBD-II port, just like the myriad of other engine monitors out there.)

 

I have yet to install an aftermarket coolant level alarm, but the plan is to utilise the sensor, run a length of twin cable thru the bulkhead as described by kjo7xk, to a dash mounted 12v flashing red LED like this;

Not sure where I will mount the LED as yet.

 

For the 5.0 engines , the coolant sensor is useless. If the owner is waiting for the reservoir sensor to warn them of low coolant…. The engine may very well be cooked! When the coolant reservoir drops there is usually zero coolant in the engine. Thats why owners have experienced shutting their cars off immediately upon seeing the warning and the engine has already blown the head gasket or worse destroyed. I’m talking about the 5.0 engines. Personally I check my coolant level EVERY TIME I take my car out for the first drive when cold. We have no temp gauge and the sensor won’t tell you when the engine is low on coolant other than the reservoir …. Too late.

 

Or... open the hood at every gas stop, car wash, or whenever you smell coolant??