Just trying to figure out what is typical for the tempeture of the heat (out of the vents) out-put on these XJs. Mine is an 01 and the temp of the engine stays right under 210 all the time. Recently the tempeture here in NC has taken a dive and gotten into the 20s and even teens. In 30 degree temperetures, under steady exceleration my heat gets, well i dont know if i would call it warm, its just decent. when it hits overdrive at highway speeds and the rpms drop it basically blows out a breeze. Same with at idle when stopped. Kinda has a hard time keeping the cabin warm. It never gets hot like my other vehicles did. Is this just tipical for an XJ or have I got an issue. I dont think the heater core is going bad i dont see any moisture or water on the floor and the heat has been like this since i bought it and I had it last winter too.

 

Mine blows super hot, when its 15 degrees outside, once the engine gets up to 210 I turn on the heat, and within two minutes its hot in the cab.

 

Does it blow hard out the vents or lightly? Explain you breeze. XJ"s are noted for vacuum leaks and your heater vents and stuff are controlled by guess what. The blend door is also vacuum related so vacuum leak = poor heating. My issue was the vac line under my battery box, I only had heat on defrost before I found that one. Check them vac hoses man

 

X2, heater should get the cab hot.

 

Thanks guys, ill check the vacums. anybody got any diagrams so i can find all of them. Are most of them behind the dash?

 

You can cook meat on my 99 which is the same cooling system.

The #1 and #2 suspects for this are a partially clogged heater core or a blend door issue.

If you have "warm" air, it is probably the heater core. You cannot tell the condition of the heater core.

Flushing it sometimes restores function. I normally use a garden hose and backflush both ways. If that doesn't work, I use the CLR flush.

 

how do u go about flushing the heter core. can it be done without removing the dash?

 

I relate my heater to an easy bake oven. It gets hot enough to bake cookies and its been 10* here.

Check, blower speed relay, heater core and the what not.

 

See link one post up.

 

whoops, yeah i saw that when i looked again. missed it the first time. thanks!

 

my 98 will cook you out of it

 

Nice! I just checked the vid out. Im going to try it out tomorrow morning. Thanks again guys!

 

dont rule out vacuum leaks. its the easiest first step and its free. start under the hood and look at the small lines going into the firewall on the passenger side. trace them around under the the battery box and see if there are any slices, breaks or unhooked vacuum lines. once you ve traced all you can see then move on to possibly flushing the heater core. i personally would check lines FIRST...

 

Ill check the lines as well tomorrow. Im gonna try to fix everything to make sure it keeps me warm through this unusualy cold NC winter.

 

Well I got a late start today but finaly got my XJ over to the shop. After i inspected all the vacuum lines (which apeared to be fine) I flushed the heater core both directions with a water hose. Then i ran some CLR into the system and let it sit for about 30 minutes, then flushed it all back out again (much like the guy in the vid). Put it all back together again and like magic the heat was working great. It produced more heat when i first cranked it up then in did before when i had been riding for a while. Thanks everybody for the tips!