I am randomly getting an "Engine Coolant Low" light while driving my '06 XK8. Checking thee coolant level shows it to be at or near the top. Engine temp is always in the 'normal' range. My local mechanic think the float my be sticking.
Has this occurred to anyone else? Any suggestions on solving the problem.

 

Sticking float is not uncommon. I'd just replace the header tank, as they are not terribly expensive.

 

Are they available new, or on eBay?

 

Available new. Think around $30.

 

Don't buy a used one, as they all spring a leak eventually, and you'd be buying something that could just give you problems. Have a look at SNG Barratt's website.

 

Thx. Barratt want $160.

 

Their aftermarket one is $70: https://www.sngbarratt.com/English/#...a-7391a91ea0bd

 

Thx.

 

I know the XK8 tank was a lot cheaper than my 00 XKR tank, which was like $150. I have burns on my right forearm (investigating overheating and the hotplate weld went when I was investigating) that would make me pour out $1500 for that tank in advance. The float, cap and tank all were in that price when I bought genuine Jaguar (not sure there was an aftermarket 6 years ago?).

I also recommend replacing the plastic norma-connector'ed lines that go to and from the overflow tank. They were brittle and broke when I did mine at the same parts age your car is now (I did this 6 years ago and my car is 6 years older...).

 

Same random message problem. Are aftermarkets usually as good? For instance, are aftermarket water pumps are still plastic impeller? Are Jag OEM metal?
New Jag owner here. This site is great.

 

When I replaced the Water Pump on both my 4L XJR and my 4L XKR; I went with AC Delco for both, they were metal impellor, and the XJR was good 20k miles later when I sold it, and 30k later on my XKR its still good. I know theres lots of discussion on coolants and impellor types, I just went with those and they worked so far.

 

After watching the "Engine Low Coolant" light come on for about 3 days, with no rise in temp, I finally added about 1/2 cup of water to the tank. Light has not come on. Seems to be full.
Nothing is mentioned about a water antifreeze mix in the manual. Is this a problem? I still have a new tank coming, and will likely replace the existing one. Maybe flush and refill the system at that time??

 

I had the "engine coolant level low" warning appear while out in the car yesterday, so, given how critical the coolant level is, what should you do when you are out there with a hot engine and this happens, you can't simply stop and top it up because the engine is so hot. Do you park up and wait 1-2 hours for the engine to cool or pray and carry on asuming that there surely must be a considerable margin of safety between the light coming on and overheating?

When I got home (only around 10 miles) I waited for the engine to cool before topping up only to find the header tank to be already full.

I read on here about the float sticking and someone suggested "having a poke around in the header tank with a stick" may free it, well I didn't use a stick but I poked around with a length of rubber hose and it did the trick, float freed and light off.

Could this occurance be a one off or will it likely happen again in which case I will look at replacing the tank. One thing that just occurred to me is how does a float get into a low position in the first place when if tank is full, you would assume this can only be due to the fact that it is not indeed floating, but then it wouldn't be fixable by tapping it with the hose?

 

After adding about 1/2 cup of water to my tank, the light has not come on for about 2 weeks now. 1/2 cup!!
I will likely still replace the tank as I Just received a new replacement, and then I will have a seemingly good extra tank.
Still wondering about the filling. Water and antifreeze, or just antifreeze. Not much chance of freezing here in S.W. Florida.

 

Antifreeze isn't just to stop freezing, but also has corrosion inhibitors. But if you're talking about a small amount to top up the tank, water will be fine.

As for the light coming on, these cars have a pretty low volume of coolant so any drop in the header tank can cause the light to come on - bear in mind that the header tank is supposed to be full, not have an air-gap at the top unlike most other cars.

 

I know about the extra properties of antifreeze, but did not know about the tight fit needed for the header cap. That could have been my problem all along.

 

Unless the antifreeze is labeled “prediluted,” it should be mixed with water (preferably distilled) in a 1:1 ratio.

 

I find that the car has to be completely cold to get a proper sense of the coolant level.

leave it overnight and check levels before starting the engine.

 

I have had this issue on my 2002 XKR for years and remember all too well the horror of the first time the red light and warning message went on. My temperature gauge never moved and I nursed the car home, let it cool off, opened the cap to find that the coolant level was within 1" of the top of the neck. I added less than 1/2 cup of coolant, restarted the car, and warning message disappeared. Yesterday, while driving in 100*F weather in Los Angeles while driving up a hill, the light went on. I haven't been driving this car much in the past couple of years, so I was a bit nervous. But when I got to the top of the hill on to flat pavement, the light/warning would go off and then randomly appear on and off for the rest of the afternoon. This confirmed to me out of experience that it was probably a tiny bit low and below the sensor, so I didn't worry about it. This morning after the car cooled off over night, I checked the coolant level, and again it was maybe an inch below the neck, so I added about a cup of coolant, no more warning, and drove it all day in similar heat with no problem. The sensor is in a spot that requires the level to be just below the cap to not send a falso warning. I am in the habit of checking oil and coolant level before I start my cars in the morning, and I had the car serviced about 2 weeks ago, so I didn't believe I had a real problem.

 

This thread is timely. Yesterday my low coolant light came on for the first time. Discovered my coolant, brake, oil, gas, and washer fluid were all a bit low. Topped each one off and hope I put the right stuff in the right hole.