Hello, new member. Long time car guy. Here's what I did that I should have known better.
First I would like to thank you guys out for all the help I have received here. I took my car in on trade at my old dealership and I couldn't help myself. Best bang for the buck in a car. Had low coolant light on when I traded for it so I gave cautious money for it. Topped off the coolant with bottled water...light went out...bought the car. It's awesome.
So it's been over a year and some 12k miles later and the check coolent light comes on periodically as is common with these cars...I have a leaking thermostat tower at the thermostat coupling best I can tell. I need to get the whole tower as I feel I may destroy my current housing if I attempt to unbolt the plastic that has aged to feel like a fossil.
For over a year I have added water at a rate of maybe one gallon total, about a pint at a time as the light came on.
Then the light stayed on.
Over time I have diluted my antifreeze mixture of Dexter to less than it should be. The light was really bugging me.
I found a you tube video of a guy explaining how the float in the expansion tank won't float in water, but floats like a champ in coolent.
I measured it with my coolent device that I would assume measures specific gravity, and it was indeed a low mix.
My jacked up method of correcting this was to used the bulb in the device to suck out the mix in my expansion tank and refill it with straight Dex...the correct pinkish red stuff. Light went off. Ignition to on tells you, no need to start her up even.
When I did crank it up the coolent, of course, circulated through and the light came back on. Hate lights.
After rinse and repeat about 5 times things got noticeably pinker. Light is now gone. I hope this helps someone out before they buy a new tank/sending unit/water pump/cap or just stresses over the light. Now I only have the cruise unavailable check rear lights message...the old break light switch. I love my XK8. Didn't know one thing about them and you guys have helped me save this steal of a 80k mile GT. Thank you all.

 

Here she is. I have bought and sold 1000's and 1000's of cars and trucks over the years. Nothing gets close for the $'s for these cars IMHO.

 

Welcome, and of course check out the new member deal for the forum.

Thank you for the info on the mixture research, I have never heard of such a situation where something will float in one solution and not in the other, but hey, you live and learn and I'll do the test myself just to see.

Great cars and can be wonderful rides but at other times hair pulling beast, but generally something simple . Yours is a beauty..

Cheers

 

Thanks Chuck.
That's why you need the 4runner or such next to it...so you can always get to work if something goes wrong....until things can be sorted out.

 

Welcome, IMHO get that tower fixed along with the crossover pipe as soon as possible. I would also check all hoses and replace if needed. These cars don't like to be overheated. If you overheat there is a high possibility of the valve seats comming loose and you will loose the engine. Also depending on year of your car, pull the cam covers to check the tensioners to see if they have been replaced to steel body. These cars are a joy but you need to take care of maintenance.

 

Tower and hoses coming very soon. Mines a 2005 so the tensioner are good to go.
I do need the regular stuff as well...shock towers, brake switch. Have to eat the elephant one bite at a time. I agree...do not get this motor hot...ever.

 

Hey i was wondering...when your low coolant light went on was it the amber colored light or the red light. I think they both read the same thing which is " low coolant" or something.

 

It was the red one. It was unnerving to see it on. I was getting ready to get a new sending unit when I found the video of the guy showing the coolant having far more buoyancy than water...so the mix ratio had slowly been diluted by me adding small amounts of straight water.
Once I got the ratio correct, the light hasn't returned and I can get a new thermostat tower instead of starting with the expansion tank sensor.
As has been stated before, just shotgunning in new parts can be a waste of money spent on the real culprits.

 

ive only had my XKR a little over a month, but i remember the "punched in the gut" feeling when the "suspension fault" warning came on. i literally pulled over to the side of the road and wanted to cry. instead, came on the forums and read about seat wires being pinched, sometimes causing crazy messages...i adjusted the seat, and the light never came back.

i LOVE these forums.
glad you got your issue sorted. relief, huh?