2001 xk8
low water light came on, went straight home with NO overheating. Let the car cool off…
low water light is on
passenger side water hose on top going to radiator is collapsed
as soon as I open cap on water tank the collapsed hose corrects itself back to normal
water level in black water tank is at bottom..
pulled liner on passenger fender well and expansion tank is full
any ideas as to why I have this scenario..where next?
car runs perfect and oil is perfect as well.. level and no water contamination
thanks in advance..

 

I guess the coolant to the expansion tank is not symphoning back into engine. Tank is 2 months old( no leaks)

 

My guess is coolant cap is faulty and/or line from reservoir to atmospheric catchment tank blocked/clogged?

 

^^ I concur....

 

FYI: the low water warning will come on way before the coolant level drops enough to cause overheating.

it only takes about one liter of coolant missing / drop to activate the warning light. That’s about all the expansion tank holds.

Z

 

It might be that the dip pipe from the black remote header tank to the bottom of the atmospheric expansion tank has been pushed into the expansion tank too far and has not been trimmed with a sloping cut and is forming a seal on the bottom of the expansion tank. Easily corrected by trimming the end of the dip pipe with a 45 degree cut.

Either that or, as said, a faulty header tank cap.

Richard