Hey all,
I've been having some issues with the heating in my 1987 XJ6 4.2...The heating works fine when the car is warm (indicating 90 degrees + on temp. guage), but here is virtually no heating below that temp (fan blasts cool air when set to max heat). Also, it takes the car 25+ minutes to warm up. Is this normal? Is there any way to get it to warm up quicker? Perhaps by changing the thermostat?

Thanks for your help
Cheers

 

There might be more to the problem but I'd begin by changing the thermostat, yes.

Watch for seized bolts at the thermostat housing. Best to work them out slowly with plenty of back-n-forth action....and even then they are known to break.

Cheers
DD

 

I would almost count on the long bolts (uppers) breaking the heads off. Plan on removing the water rail and working them out on a bench. I broke one of mine and so far have just left in that way without a problem. Why was I tampering with them you ask? Well I thought I would get them out as a PM measure and put anti-seize on the threads so that when the t/s was ready to be changed, it would not take as long. Well the bottom one came off ok (nut and bolt) but the first long one broke and I didnt even try the second one. My plan is to prepare a water rail from my parts car (those bolts broke too) and just swap t/s housings.
Good Luck!

 

Just to vent a little...would it have been so hard for Jag to put the thread end out on that housing? That way all we would have to do is remove a nut instead of a long threaded bolt that was destined to rust in place? You would think the engineers would have seen that one coming a mile away. Ok, I am done venting.