Change Thermostat Without Draining System?
CF Veteran
Joined: Nov 2009
Posts: 1,262
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From: Conroe, Texas
Year: 1997
Model: Cherokee
Engine: I6
No need to drain but you do loose a little coolant......just top it off when done. Personally, I prefer the 180F t-stat and the heater works plenty good.
What's accurate about a temp gauge that goes to 210F and just stays there. I've never seen a factory temp gauge that's much better than an idiot light but hey, at least the XJ gauge has a few numbers vs C and H like most factory gauges. I use a ScanGauge and know exactly what's going on with regard to coolant temp and the coolant temp does NOT go to 210F and just stay there.
What's accurate about a temp gauge that goes to 210F and just stays there. I've never seen a factory temp gauge that's much better than an idiot light but hey, at least the XJ gauge has a few numbers vs C and H like most factory gauges. I use a ScanGauge and know exactly what's going on with regard to coolant temp and the coolant temp does NOT go to 210F and just stay there.CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
supposedly these jeeps have to hit 190 temp or it will go into open loop or closed loop.....i get those mixed up i cant remember, but if its too cold the computer will keep dumping twice as much gas in the motor thinking its still cold trying to get it up to its 190 operating temperature. IMO i'd stay with the 195 T-stat and let it run at the temp it was made for. i like cooler engines, cuz all heat does is ruin stuff but its made for the 195. other smarter guys will chime in on this im sure
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Junior Member
Joined: Dec 2009
Posts: 80
Likes: 0
From: Herriman, Utah
Year: 1996
Model: Cherokee
Engine: 4.0
Picked it up at Autozone. Don't know the brand... cheep, asked for a 170 now i run at a steady 170
whoever installed the last one put in a 230 that was pissing me off.
My bad It was a 160. I run a steady 10-15 over constantly, so I run a 170-175.
whoever installed the last one put in a 230 that was pissing me off.
My bad It was a 160. I run a steady 10-15 over constantly, so I run a 170-175.
Last edited by Silly Willy; Jan 23, 2010 at 10:14 PM.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Thanks, all I'm familiar with are either 160F, 180F and 195F t-stats. Are you going by the factory gauge to determine your coolant temp? Are you using an aftermarket temp gauge?
Last edited by djb383; Jan 24, 2010 at 10:04 AM.
CF Veteran
Joined: Jun 2009
Posts: 5,383
Likes: 5
Year: 1988 limited
Model: Cherokee
Engine: 4.0 litre
Coolant temp has nothing to do with the system going into "closed loop". Don't know where this info gets started but it's just wrong. The "loop" closes when the upstream O2 sensor(s) reach +/-600F and begin sending rich/lean info to the ECU. A heated O2 will reach that temp within a few seconds after engine start-up. Maybe takes a minute or so in extreme cold conditions before entering closed loop. We get consistent 14-16 mpg stop-n-go city driving and 20-22 mpg steady hwy driving with a 180F t-stat installed. In the pic below you can see that the ScanGauge shows that the system has entered "closed loop" and coolant temp is only 94F.
Seasoned Member
Joined: Mar 2009
Posts: 308
Likes: 0
From: Space Coast, Fl
Year: 1998
Model: Cherokee
Engine: 4.0
ok guys this might have been answered but i am running a 160 t-stat whats so wrong with that..... i am just trying to figuer some stuff out casue i am getting about 15city an 15highway.... but also my down stream o2 an cat are going bad but will be replaced this week
Junior Member
Joined: Dec 2009
Posts: 80
Likes: 0
From: Herriman, Utah
Year: 1996
Model: Cherokee
Engine: 4.0
Don't know if thats the t-stat or what..
CF Veteran
Joined: Nov 2009
Posts: 1,262
Likes: 0
From: Conroe, Texas
Year: 1997
Model: Cherokee
Engine: I6
Junior Member
Joined: Dec 2009
Posts: 80
Likes: 0
From: Herriman, Utah
Year: 1996
Model: Cherokee
Engine: 4.0


