Bad heater core/Thermostat issue?

95Trooper

Well-Known Member
Joined
Mar 23, 2008
Location
WNC
Hey guys, just got a 98 XJ and I’m having some issues with the heat. It gets warm but not hot hot. Coolant level is good and I backflushed the heater core. It did have some mud and dirt in it but I ran the water through it for awhile and it came out clean. Here’s the thing, the temp will only get up to the notch before 210. I’m thinking the Jeep has a 160 or 180 degree thermostat in it. Could that potentially be the problem? They call for a 195 degree thermostat factory. What thermostat do you guys recommend? I’ve always had bad luck with parts store thermostats failing...
 
I have a 195*

Never gets close to that in this weather. However, I do get good heat.

Change your thermostat may be hung open.
 
I DD a 99 XJ with a 195 degree thermostat. Same struggle with heat. I found that my climate control gate motor thing under the dash on the passenger side doesn’t move to heat all the way. Try removing yours. The gate defaults to maximum heat. I am about to do that to mine. It should be warmer.


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Hmmm like I said I just got the Jeep this week and haven’t had a lot of time to tinker with it. It gets warm, warm enough to keep you that way but not HOT like these XJ’s usually put out. I’ve had several of them. A lot of people will run a lower degree thermostat (160 or 180*) during the summer to make them run a little cooler so I was curious if maybe that’s the case here and it’s not reaching full (normal) operating temp.
 
I advise against a 160 or a 180 tstat. I did that for a while and never knew how bad it was to keep the motor down to those temps. If it isn't overheating then keep the 195 t-stat in.
 
Before you buy anything, are both heater hoses the same temp at the heater core? If not, there's still a restriction.
If so, it's likely the thermostat as already stated.
 
Jody Treadway said:
Before you buy anything, are both heater hoses the same temp at the heater core? If not, there's still a restriction.
If so, it's likely the thermostat as already stated.
Click to expand...
One day you should write a comprehensive write up on jeep cooling issues
 
My preferred flush method is water pressure followed with a blast from the compressor. Works much better, though I'm always concerned about dislodging crap that's stopping a leak. Fun fact: radiators will flow a garden hose through just two or three tubes in the core.
 
Are XJs bad about getting leaves in the heater box? I think the only way I'm going to finally get @trailhugger's TJ working right is to pull the dash and clean the box out that way. I've pulled a shit ton of willow oak leaves out through the fan hole and the resistor hole, but it's still not clean.
 
shawn said:
Are XJs bad about getting leaves in the heater box? I think the only way I'm going to finally get @trailhugger's TJ working right is to pull the dash and clean the box out that way. I've pulled a shit ton of willow oak leaves out through the fan hole and the resistor hole, but it's still not clean.
Click to expand...
Xj boxes stay pretty clean . My TJ heat sucks compared to the old YJ. I really want to dump it instead of fixing it but I'm too cheap to let it go cheap!

Just plan on changing the heater core and be done with it. It's not as bad as it is make out to be if you have any mechanical skills.
 
GotWood said:
Just plan on changing the heater core and be done with it. It's not as bad as it is make out to be if you have any mechanical skills.
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Oh, it's not my first time having one apart... But, lazy. Also, other priorities.

And yeah, if you get one that far apart, plan on replacing the heater core and evaporator coil. If you don't, they'll start leaking within a couple of weeks. :rolleyes:
 
@shawn evaporator core. Drives me crazy people calling cores "coils". Yes xj boxes stay pretty clean, they have that mesh plastic over the wiper area and it's closed off over the top of the intake, drawing through the side vs the top.
 
a_kelley said:
@shawn evaporator core. Drives me crazy people calling cores "coils"
Click to expand...

I don't remember which it is. Some are cores, some are coils. Both do the same job.

TJ intake is under the cowl, has a plastic hood over it, still sucks up willow oak leaves.
 
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