So…. Took my ‘97 XK8 in for a checkup after “check eng, poor vehicle performance” light, etc, with a resulting diagnosis of bad radiator hoses and cooling tower. Tstat not registering as high as it should be. Hoses replaced, new coolant tower.. $1700. 2 days later, 75 miles from home, light comes on again. I see nothing wrong, EXCEPT that the dash gauge was waaay below usual midpoint . My understanding is it might indicate tstat stuck open, system not bled properly(when I picked car up after service, heater was on high, indicating someone checked it). Taking it back in early in morning, any tips on what I need to ask or say?
BTW, 75 miles from home & no desire to make things worse, AAA towed the Jag and it was a long-*** day, long-*** ride through rush hour traffic. At 50mph…….

 

I had exactly the same problem on my XK8, low coolant temp on highway but okay in traffic. If you have code P0128 as I had that indicates "Engine not reaching operating temperature".

A new TStat fixed the problem, surprised your garage didn't replace the TStat with all that engine cooling work, though under test my TStat did look okay and opened with boiling water okay.

But that was under test.

 

Yup, the whole tower was replaced, with upper & lower hoses, was told that the t-stat was not allowing it to reach temp. And I saw that they had checked before I picked it up, heater was on full blast. Thank God for Forum , I looked up issues as I sat waiting for tow truck 70 miles from home(AAA). Just was not going to chance driving it that far(listen, I’m 75 and not limber). Pretty much thinking system maybe wasnt properly bled(I’m not savvy enough to guess and diagnose, & no code reader), as the gauge
never made it to that golden mid-way point.
So…. Original mechanic will look again.
Is it way too early for a little something in my coffee?
9:30am. I appreciate the input!!

 

It's never too early, the sun is over the yardarm somewhere..