I have a 1996 XJ6 (US) where the engine temperature gauge barely budges, and the heater never warms up. Air conditioner works fine. Coolant hasn't been changed in a long time. Engine fans run.
Could this be a thermostat? If so, where is this located? I'd like to try and change it myself if not too hard a job.
thanks for any suggestions.

 

Welcome to our world.

When you can, PLEASE do an intro in the new members area, It just keeps the Moderators all warm and fuzzy, and is really the right thing to do.

The thermostat is most certainly jammed OPEN, quite common with age. It is located under the alloy housing at the very front of the engine with the top radiator hose attached.

Replacing is simple enoough. Just be aware that some suppliers list an o/ring for that housing joint, NO. It is a standard style gasket. Fitting an o/ring will break that housing, and upset you.

Holding the new thermostat in place whilst the cover is slid into position can be tricky, gravity is a bugga, so a dob of RTV on the rim of the stat holds in in place without issues.

I am not familiar with USA spec cars, and the under bonnet stuff that may hinder access, but down here there is nothing, and changing the thermostat is about a 15 minute task.

 

thanks, I was able to change the thermostat very easily and the engine temp now comes up to the normal range. But the heat is still blowing cold air. Any suggestions? The radiator seems to be clear of an debris.

 

Welcome to the forum,

Don't forget that intro!

 

OK, sort of good news.

On the LH side of the engine bay, near the rear, are the heater hoses, AND, a smallish rotary "pusher pump" that assists the flow of coolant TO the inside heater core. Maybe it is not working.

Also, the heater core may well be blocked. Sooooo, disconnect the hoses, and using the garden hose, CAREFULLY, flush it in both directions.

After all that, the lack of heat may well be a gremlin inside the system inside the car, but, being as how that is Nippon Denso, and extremely reliable, I seriously doubt it.

 

Welcome to the forum. Grant is steering you properly, as he always does!

See post #2 by Bob, for the TSB's, here: https://www.jaguarforums.com/forum/x...winter-102192/

Also some links there to pics of the heater pump and water valve that may or may not be useful to you. I had that problem for a couple of years, and a drain and flush with distilled water, + hosing out the heater core seems to have done the trick. If your heater pump is the culprit, do a search, one of the members posted up a nice how-to with some great pics for changing out the brushes and bringing it back to life.

 

Thanks! I'll give the flush a try and report back. And FYI, I did fill out my new member intro, let me know if I didn't do it right.

 

It's possible that the system has an airlock and just needs bleeding