Going down my "to do" list on the '01 XJ8. While still keeping an eye on my bank 2 knock sensor giving me intermittent "restricted performance", my next agenda item is getting some heat in the cabin. Heater has not worked since I bought the car early spring - but here in NC the A/C working was way more important ! As we get closer to mornings flirting with below 40 deg, time to look into it. Yesterday, I replaced the auxiliary heater pump (just because I read it was the nr.1 cause of the malfunction). Unfortunately, this was not my problem (and found out my pump was working just fine - testing after the fact, stupid me). Next, I am thinking I am to replace the heater valve. So I'm throwing this thread out here just in case someone has experienced something similar but the problem was not related to the standard problems already found on the forum.

Stay tuned with more Blue_XJ8's agenda of stuff to fix. Next is the driver door no longer locking.

 

any advice on this mans Heat issue anyone?

 

Check the Valve before your replace it. They can be cleaned and unfrozen.

I checked my valve and pump and both are fine so now I'm guessing it's the thermostat.

Good luck.

Eric

 

where is the valve?

 

Heater valve or heater core flow.

bob gauff

 

Check the thermostat it might be in a open position, the coolant will never reach operation temp.

Those it heat up while sitting idle and cool off when you start to drive, if so stuck open thermostat, need replacing.

 

now my gauge is always in the cold temp zone, and i get heat but not crazy hot heat, do you think its the thermostat? i just thought it was that silly gauge problem

 

99.9% sure it the Thermostat

$18.00 part, 5 mins and three bolt you will have heat.

 

does the coolant need to be drained?

 

Thanks all for replies, and sorry for late follow up. So the latest on my end is that I am getting warm air, at most, after 20min drive or so with heater on "HI". Additional note is that the warm air comes out of driver side vents, not passenger side ! Not too sure if this is any kind of indication, but would think more towards the core than the valve. Probably not bad to clean/replace the valve, but sounds like I might need to clean / flush the core?

 

The heater core is like a radiator, it just have fins and tubes, the coolant heats of the core and the blower blowes the air. If the core was bad it would just leak, see if the carpets are wet/damp. If not the core is good.

Since you have air flow the blower motor is good.

I still leaning towards the thermostat, stuck open. If you getting warm air flow from one side and not the other, the vents could be stuck, that can happen if the vents was ever removed and not reinstalled correctly.

The heater valve is a open and close part, like a light switch either on or off. But, since you say it warm air, it is flowing. Maybe it half way open. Still leaning towards the thermostat.

 

I see my local supplier sells a kit which includes the thermostat, the gasket and the housing. Is buying this a good idea as I don't want to suffer any downtime.

Basically how likely is it that I need the housing as well?

Thanks

Eric

 

If the housing on the car now is plastic and the new one is metal, go ahead and get the kit.

If not, all you need the the thermostat and gasket. You will have to remove the housing anyway to change the thermo.

 

Are they usually plastic on a 2000?

Thanks

Eric

 

I don't know which MY they switched over to the metal housing, the best way to find out is pop the hood and check. Maybe if it was, it was already replaced by the pervious owner, like my was.

 

Mines plastic. Damn. I picked up the thermostat and no housing.

How likely is the plastic radiator drain plug to snap off in my hand. It looks pretty frail.

Thanks

Eric

 

All radiator drain plugs are plastic, so no worries there.

 

Ok so I got my old thermostat out and I tested it. It won't open in boiling water.

The new one opens at about 185 like it is supposed to so I put it in, filled up and heated up the engine cycled the heater and still no heat.

My auxiliary pump and my valve both work. The coolant is clean and the correct orange jag coolant. I suppose the core could be clogged but I doubt it.

Is there some other thing I should be looking for? Is there a cold/hot air vent or door that might be stuck?

Thanks

Eric

 

62sunbeam did you have to drain the coolant when removing the thermostat?

 

[QUOTE=Safi;622730]62sunbeam did you have to drain the coolant when removing the thermostat?[/QUOTE


Yes I did. Why?

Thanks

Eric