So I picked up my XJC 4.2 on Friday after a short spell at the shop where the main task was to complete a Euro bumper conversion and side tasks included tightening the head (new gasket, crank and other things 2000 miles back), new water temp sensor and putting the rad fan on the right way around (long story).
And I was feeling very happy with all the above, in particular the well behaved engine temp even while sitting in horrible Parisian traffic. I put the air con on as it was getting warm. And shortly after I heard a « pop » and engine temp rose sharply to the « l » of normal (previously around “r”).
Obviously a sign something untoward in cooling and yes should have stopped for immediate inspection but impossible in circumstances and limped the remaining mile (15 mins) home, during which time the temp gauge hovered around the same before dropping a bit when I was able to pick up speed.
Not difficult to diagnose: lower radiator hose had come free. So basically last stretch was air cooled. Ugh. I was actually surprised engine temp had not gone off the scale.
My two questions are
(1) Cause: most likely hose simply carelessly refixed, but could there be something else at play? The fact that I put on the air con just before may have been coincidence, or might have created some sudden load which caused rise in pressure? (I had used the air con earlier in the run too without ill effect).
(2) Effect: clearly I will check for head gasket damage by looking for exhaust gas in coolant once hose re-attached and coolant refilled, and any other general issues, but is there other more specific collateral damage I should look for ?
I know it is a robust engine but also that it is not fond of overheating.
Thanks very much.
XJC 4.2 (1976), Paris France.