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thermostat

D

Dave Meyers

NAXJA Forum User
Location
Kenosha, Wisconsin
I have a 2000 XJ with supposed stock replacement T Stat and poor heat. Where does a proper running temp. gauge read when warmed up? Mine is about half way between the 210 mark and the one to the left of it. I get heat, just not like it used to be. The blend door works, in that the temp. adjust knob changes the temp in the cabin, it just never really gets very warm. Its a little better on recirculate. I put it a 195 degree T stat with new radiator and water pump recently. Wondering of the T stat could be defective, or could the blend door be "partially" working instead of all bad. Input and output hoses to heater core seem equally hot. Appreciate all help. Thank you.
 
"supposed stock replacement"

Does that mean you bought it from the dealership or from the local fast food parts store?

Cheap thermostats from the local parts store have been know to open prematurely, causing your jeep to run too cool.

The fix is a thermostat from a Jeep dealership.
 
My 2000 holds a steady 210 unless low speeds and <20 outside. Then it drops to 205.

I would pull the blend door actuator motor (3 small phillips IIRC) and try moving the door shaft by hand. See if it gets hotter when you turn it all the way. You could mark it with chalk or white paint for full travel. Then put the actuator back on and see if it travels as far.

Be carefil though. They are known bor broken blend doors. Some guys on ebay sell a repair kit to replace the broken blend door. Mine is always hot anyway, so I always back the temp down from maximum to reduce stress on the blend door.
 
Thanks guys, I will look into both issues. yes, I bought a T stat at auto zone, not Jeep. I 'll replace that AND look at the blend door. I want more heat. I actually borrowed my wife's Liberty today to do errands because I wanted to stay toasty.
 
Is your heater core clogged? This can cause poor circulation/heating.
 
When I replaced the radiator I flushed the heater core til it ran clear, and it seemed to flow very easily as tho not clogged. Does my 2000 have a bypass valve? Where might that be?
 
robsjeepxj said:
No, I would put my money on the t stat. I guess I don't have to ask about fluid level and quality right?:shhh:
Click to expand...

Radiator is full to the top, but the catch bottle is empty, which concerns me, because it was only months ago that It was full. Engine compartment is dry, no evidence of leaks, no oil in coolant or vice versa. Quality is good, because it is relatively new and 50/50 mix. I will try a new T stat first and see what happens. Then look at the blend door if still needed, and snoop around for leaks and check that bypass valve, too.
 
Suspect the IdiotZone thermostat. Perhaps with low coolant you have an air bubble in the cooling system. The bubble will stall the flow of coolant and your heater core output will low.
 
To self purge the air out---that expansion tank must have fluid at ALL times. Engine at running temp expands coolant AND AIR out to expansion tank, then when it cools down pulls only coolant back. A few hot-cold cycles pumps the air out.

(DO NOT OPEN RADIATOR CAP or have to start over.)

Good Luck,
Orange
 
Stant SuperStat Premium 195 degree thermostat.

Nothing better.
 
Update: I tested the T stat on the stove and with a thremometer, opened at 195 degrees, closed slowly starting at same, but replaced it with a new one anyway. Filled cooling system and overflow tank, cycled it a few times, no change in heat. Blend door and motor are working. Maybe the heater core is not as clean as I thought it was, or the blend door is obstruced at full close, only ideas I have. I have some heat, not enough though. Or, could it be a bad fan clutch?
 
Last edited:
I had a generic 195 thermostat in mine and it caused the jeep to run at and a little above 210 according to the gauge. I recommend only replacing with a Mopar thermostat because it has the little bleed hole most aftermarket ones dont. When I replaced with the Mopar one it now runs right below the 210 mark on the gauge. It also has much better heat. If you haven't, replace your radiator cap and check your coolant overflow hose to make sure it is not clogged. Mine was and it didn't allow the air to escape the radiator. Fill your overflow bottle up too, that is a must! Good Luck.
 
I'm gonna replace the anti-freeze, thermostat, radiator hoses after I flush the system in my "97 XJ.
Question: does the thermostat housing have a gasket or "O" ring?
where can I get some part numbers for the radiator hoses?
Also gonna replace the serpentine belt, any suggestions on
brand/type or part numbers for the hoses also?
Thanks
 
Most parts stores have competent counter people that can look up part numbers for you.

You will have to tell them what year/engine/accessories you have to get the right parts for you.

Hoses--Gates all the way.

Belt--Goodyear Gatorback.

If you have a 4.0, then you need a gasket for the t/housing.

I recommend the Stant SuperStat Premium 195 degree thermostat, and nothing else.
 
joe_peters said:
Most parts stores have competent counter people that can look up part numbers for you.
Click to expand...
Unless their parts database is wrong on the part you want! For instance go to NAPA and ask for a transmission filter+gasket kit for a Cherokee with an automatic and you will get the kit for some 3-speed Chrysler tranny never used in the Cherokee (or was the 30RH used, but only on earlier years?)* You have to ask for an ATP B112 kit to get the right one for the AW4 - and it's $45! Ask me how I know...

Amazingly, I've had great luck with autismzone Duralast thermostats. I don't buy there anymore (till I finish dealing with customer satisfaction anyways), but the one I just put in my friend's 91 MJ is working great, gas mileage went from about 9mpg to 17.5 and his heat works again. Looks like Advance Auto Parts carries Stant for a few bucks more than AZ charges for a Duralast, guess I'll switch in a hundred thousand miles or so.

* looks like I was wrong, their computer just thinks all cherokees use the 3-speed automatic tranny for the I4/V6 engine.
 
Last edited:
I recently replaced my leaky radiator (148K miles) and installed a Stant 195 tstat.
Noting that it didn't have the bleed hole like the stock one does, I thought to myself......."Self, you have a drill bit that is exactly the same size as that bleed hole"........you guessed it folks, I made my own bleed hole!

Seems to work just fine, however I did notice that my temp gauge shows 195* unless I'm really leaning on it hard, then it goes up to 205*. Prior to this change, my temp guage spent most of its time at 210*.
 
unless the bypass valve is screwed up.[/QUOTE said:
Lemme know when you find that bypass valve on ur Y2K XJ, I've been looking for one on mine for the past 9 years or so... Oh and how come none of you guys have tried using a slightly lower temp Tstat? I switched to a 180 unit, no hole drilled in it was the Napa brand and I did it when I had the old 0331 cylinder head replacement sage as a preventative measure, my heat comes on fine, nice and toasty and the temp hovers right around the 200 mark unless I'm on extended highway cruise when it seems to settle just a bit to the left of that, my MPG seems normal, no emmisions problems with around 80K miles on this mod and my otherwise stock engine, stock replacement radiator and OEM waterpump still...
Click to expand...
 
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