Hey Guys! Took the’97 xk8 out further than i’ve driven it before and 75 miles from home(from Roseville to Vallejo) and coolant warning light came on. Letting car cool down, outside of AutoZone and picked up the 50/50 pink coolant. Having a burger and asking suggestions. Car had been checked out every way from Sunday....
Cindy

 

If the coolant level is OK then you have a stuck float in the expansion tank. I have had that problem several times and rather than replace expansion tank I just bypassed the float. In doing this you must remember to check the coolant frequently because you eliminated the warning light. Some day I may get around to replacing that tank and float but it has worked well for years!

 

Before you do a top-up, check the colour of the coolant already in the expansion tank coolant reservoir. Our early cars originally had a green DOW-spec coolant which may or may not have been replaced with the later extended life (pink/orange) sometime during the car's servicing history.

Here's the chart showng the various types:



Note the warning about mixing coolant types.

Until you're sure, just top up with plain distilled or de-ionised water and see how the car behaves over the next few days.

 

While I was letting car cool down...BobRoy contacted me, asked me a couple questions, then told me not to add coolant because if PO had put wrong coolant in, it could cause a problem. I suspect not original owner but estate executor , as original guy Took immaculate care of the car.. So Bob had me add a little water instead. That did the trick. I looked up a number of things and the float being stuck was the most common. And adding the wrong coolant is baaaaad. So I do believe a flush and fill is in order
Bob, you the man....

cindy

 

Hi Cindy,

So was your coolant level actually low? If so, then it seems like your coolant sensor is working just fine. If not, then I would suggest replacing the coolant reservoir which is pretty easy and inexpensive. The sensor comes with it. My car was intermittently showing low coolant and the red warning light and I replaced the reservoir and all is well. It was only around $50 for the reservoir from RockAuto and pretty easy to install. Finally for once there was a cheap and easy fix to an annoying problem with my Jag!

 

I agree with advice to replace the Expansion Tank because the OEM comes complete with Fluid level Sensor and Pressure Cap. Check what you are buying because some aftermarket parts suppliers sell it without the Pressure Cap.

However, there may be some who only want to replace the Fluid Level Sensor. This is available separately as P/N LNA5740AB:





I strongly disagree with the suggestion made earlier in the thread to permanently disconnect a faulty fluid sensor. I'd prefer to have false alarms rather than risk overheating a Jaguar V8 which all too easily and quickly becomes a terminal event.

Graham

 

Had the same issue with sticking float but, I saw that the bracket on the tank was bent offsetting the tank about 15* > Leveled it out, added new sensor and no further low coolant lights even driving in 90F weather.

I do have a question as to recommended period for coolant flushing?

 

dexcool is rated for 5 years 150,000 miles but can go a lot longer

 

Agree replacement of the expansion tank is a good solution. My only complaint w/ the Rock Auto replace is that I have to REALLY crank the cap down to close it. Otherwise get small traces of fluid.
Currently using a little grease as sealant (and to make it possible to open w/o using pliers). Tempted to make a small rubber gasket.

 

I use a 2015 OEM cap on my September 2017 coolant reservoir from rockauto. The OEM caps are indeed a better fit than the aftermarket ones that come with the aftermarket reservoirs....