Apparently, the amount of coolant is super critical - at least to keep the low coolant light out! I just changed the coolant in my 2004 XKR and I can't seem to get the low coolant light to stay out. Does anyone have any tricks to add enough coolant to get the light to go out? In my case I don't think its the switch because it was working prior to draining and changing the coolant. I just seem to continue to add a small amount of additional coolant each day.

 

Sounds as if you did not fully burp the system when you replenished your coolant. After I have done various repairs to the cooling system in my wife's 2006 XK8 over the years, it is not unusual for me to have to add a few ounces of coolant first thing every morning for three or four days after the job....

 

If it is the original coolant tank could it be that the float is stuck down now?

 

I always make sure the Atmospheric Catchment Tank has a little coolant to draw from when the engine cools.
XKR has more coolant than NA because of the 'charge-air' coolers and that system can be hard to fill completely.

bob

 

How do you ensure this? I checked mine a few days ago (pull front passenger side wheel well) and it was empty.

 

You can fill it some by filling the reservoir (expansion tank) FULL and placing your hand over the top. Squeeze a hose (radiator) and allow the overflow to run into the catchment tank. I do this repeatedly to fill the catchment tank level a few inches so that there is something for the reservoir to draw when the engine cools.

The cap will allow the catchment tank fluid to be drawn back into the reservoir.

bob

 

This light is driving me nuts. I have burped and burped and opened the supercharger intercooler filler and added drops of coolant. Excess coolant now appears to be coming out the atmospheric recovery bottle after I drive yet the light stays on! The light does go out...then a few miles later it comes on again. I do not want to replace the expansion tank for this non issue. Can I just bypass this sensor and turn the light out?

 

New aftermarket coolant reservoirs are relatively inexpensive (I paid about $58 total for one from rockauto.com in September 2017). If yours is more than five or six years old, it is subject to start leaking from either the hose nozzles or the seam. A new one may be your best decision in this case....

 

I had this issue a few days after getting my car and it freaked me out too. Figuring the float was stuck because there was plenty of coolant in the tank I just took a wood shim and rattled inside the tank a bit and the light went out. Last year my tank started leaking so I replaced it with a Uro replacement from Rockauto. Yeah, as I remember it was about $50 and haven't had any problems since.

 

If you've done everything to top up the water, you might have to start looking for a leak. Typical places are water pump, and Forma plastic connectors. I did exactly what you did, and still scratched my head.

 

Hi Allan, wanted to address your question about bypass. Please cross this idea off - dont even consider it my friend.

Sooner or later something's gonna leak. All of a sudden the working light will go on, you can monitor the situation.

I've had slow leaks without realizing it, been 50+ miles from home, light goes on. Gave me a chance to top it off before any damage. most importantly in this case it gave me a way to monitor the level on my way home or to the mechanic. Without that light you are flying blind -"did the leak worsen?"
You'll be wondering! It's just not worth it IMO. The risk & stress is magnified 10x if you don't have a RealGuage!

Allan, replacement of the tank is an easy job. I've read so many stories of a failed switch (resides inside the tank), none of any type of wire harness issue causing this that I'm not going to get into using your volt meter to prove this to a defective switch.

Hope you're doing well.
John

 

Is there any spec on the level in the atmospheric tank; mine is empty which doesn't seem right?
2003 XK8

 

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