Picture of good and bad new thermostats.
I took pictures immediately after pulling each of them out of boiling water. they were in boiling water for at least 5 min.
All of them brand new from NAPA.
One of them opened twice less.
All of them brand new from NAPA.
One of them opened twice less.
Last edited by Rockville; Oct 26, 2012 at 12:32 PM.
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Make sure to use the working one then.
How is the work on your cooling system going by the way? You were the one that had the system that was beyond rusty and nasty. Have you replaced all components yet?
How is the work on your cooling system going by the way? You were the one that had the system that was beyond rusty and nasty. Have you replaced all components yet?
It was kind of OK, but I felt that electrical fan was working too early. Here is picture answer.
I boiled chosen new NAPA thermostat and Advance auto one, which I installed 3 days ago.
I am going to check fan clutch too.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Why would u expose a stat to boiling water?
Why would u test without a thermometer?
Coolant in the motor shouldn't be boiling. When installed in the motor, a stat isn't exposed to the sudden cool of ambient temp either. Pics show a 180 stat under similar conditions as when in the motor.......not exposed to boiling water, not exposed to ambient air temp.
Why would u test without a thermometer?
Coolant in the motor shouldn't be boiling. When installed in the motor, a stat isn't exposed to the sudden cool of ambient temp either. Pics show a 180 stat under similar conditions as when in the motor.......not exposed to boiling water, not exposed to ambient air temp.
Last edited by djb383; Oct 26, 2012 at 01:31 PM.
Why would u expose a stat to boiling water?
Why would u test without a thermometer?
Coolant in the motor shouldn't be boiling. When installed in the motor, a stat isn't exposed to the sudden cool of ambient temp either. Pics show a 180 stat under similar conditions as when in the motor.......not exposed to boiling water, not exposed to ambient air temp.
Why would u test without a thermometer?
Coolant in the motor shouldn't be boiling. When installed in the motor, a stat isn't exposed to the sudden cool of ambient temp either. Pics show a 180 stat under similar conditions as when in the motor.......not exposed to boiling water, not exposed to ambient air temp.I could see opening gap in water, I just pulled them out to take pictures.
You don't really need thermometer. Even if you do, you need to know:
temp of beginning of opening
temp of fully opened
You also need to measure temp of thermostat, which is impossible. If water is let us say 195F, we don't really know how long it will take for thermostat to warm up to that temp. 3 min.? 5?
Boiling water is reliable and simple way to check, unless you live in mountains.
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CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Boiling water has 212F temperature. At this temp any thermostat has to be completely open.
I could see opening gap in water, I just pulled them out to take pictures.
You don't really need thermometer. Even if you do, you need to know:
temp of beginning of opening
temp of fully opened
You also need to measure temp of thermostat, which is impossible. If water is let us say 195F, we don't really know how long it will take for thermostat to warm up to that temp. 3 min.? 5?
Boiling water is reliable and simple way to check, unless you live in mountains.
I could see opening gap in water, I just pulled them out to take pictures.
You don't really need thermometer. Even if you do, you need to know:
temp of beginning of opening
temp of fully opened
You also need to measure temp of thermostat, which is impossible. If water is let us say 195F, we don't really know how long it will take for thermostat to warm up to that temp. 3 min.? 5?
Boiling water is reliable and simple way to check, unless you live in mountains.
U do know the meaning of infinite?...............................and who buys 3 t-stats?
Last edited by djb383; Oct 26, 2012 at 03:46 PM.
We check different things and you do it right.
You check temp of opening, I check how far they open. I have bought a few bad ones, so I just don't trust Advance and NAPA.
If you like wasting your time by buying bad one and then buying again, it is OK.
Or maybe you buy from better place, where?
You check temp of opening, I check how far they open. I have bought a few bad ones, so I just don't trust Advance and NAPA.
If you like wasting your time by buying bad one and then buying again, it is OK.
Or maybe you buy from better place, where?
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
I think you guys are trying to pick fly chit out of pepper.
Rockville, here are are couple of pics of the OEM 195* thermostat (which you should buy) which you can and to your collection of pics.
OEM part number 97-2K1 part number 52028186.
Note the bleed valve in the stat.


This stat is for a 2K T&C but the 8186 stat is the same design.
Rockville, here are are couple of pics of the OEM 195* thermostat (which you should buy) which you can and to your collection of pics.
OEM part number 97-2K1 part number 52028186.
Note the bleed valve in the stat.


This stat is for a 2K T&C but the 8186 stat is the same design.
CF Veteran




Joined: Nov 2010
Posts: 5,841
Likes: 117
From: In the middle of Minnesota!
Year: 1999
Model: Cherokee
Engine: 4.0
Or just buy an OEM mopar stat for about the same money and sleep easy. My experience with them is that they're the best in the business.
I have NOT had a failure of an OEM Mopar stat in 38 years. Not a bad record. No way I'm messing with aftermarket.......
I have NOT had a failure of an OEM Mopar stat in 38 years. Not a bad record. No way I'm messing with aftermarket.......
Last edited by tjwalker; Oct 26, 2012 at 06:12 PM.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
We check different things and you do it right.
You check temp of opening, I check how far they open. I have bought a few bad ones, so I just don't trust Advance and NAPA.
If you like wasting your time by buying bad one and then buying again, it is OK.
Or maybe you buy from better place, where?
You check temp of opening, I check how far they open. I have bought a few bad ones, so I just don't trust Advance and NAPA.
If you like wasting your time by buying bad one and then buying again, it is OK.
Or maybe you buy from better place, where?
I don't consider testing a t-stat prior to installation a waste of time. Neither NAPA or Advance make a t-stat. What does NAPA or Advance make......anything? Stant is the only brand of t-stat I've ever bought/used and always had good results but again, I test before installing (just not in boiling water, duh). I've never returned a Stant after testing or had one fail while in use. With all due respect, I'd almost be willing to bet that Stant quite possibly made that Mopar t-stat.
Auto manufacturers, for the most part, make doors, fenders, hoods, frames, motors, etc. Most of the small parts (maybe t-stats for example) are subbed out to be made by other companies or subsidiaries.....thus the term Original Equipment Manufacturer or OEM part(s).http://www.stant.com//Automotive-OEM...em-Components/
Last edited by djb383; Oct 26, 2012 at 04:57 PM.
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Only thing I'm picking fly chit at is the worthless apples/oranges stat "testing" method (boiling water).
I don't consider testing a t-stat prior to installation a waste of time. Neither NAPA or Advance make a t-stat. What does NAPA or Advance make......anything? Stant is the only brand of t-stat I've ever bought/used and always had good results but again, I test before installing (just not in boiling water, duh). I've never returned a Stant after testing or had one fail while in use. With all due respect, I'd almost be willing to bet that Stant quite possibly made that Mopar t-stat.
Auto manufacturers, for the most part, make doors, fenders, hoods, frames, motors, etc. Most of the small parts (maybe t-stats for example) are subbed out to be made by other companies or subsidiaries.....thus the term Original Equipment Manufacturer or OEM part(s).
http://www.stant.com//Automotive-OEM...em-Components/
I don't consider testing a t-stat prior to installation a waste of time. Neither NAPA or Advance make a t-stat. What does NAPA or Advance make......anything? Stant is the only brand of t-stat I've ever bought/used and always had good results but again, I test before installing (just not in boiling water, duh). I've never returned a Stant after testing or had one fail while in use. With all due respect, I'd almost be willing to bet that Stant quite possibly made that Mopar t-stat.
Auto manufacturers, for the most part, make doors, fenders, hoods, frames, motors, etc. Most of the small parts (maybe t-stats for example) are subbed out to be made by other companies or subsidiaries.....thus the term Original Equipment Manufacturer or OEM part(s).http://www.stant.com//Automotive-OEM...em-Components/
I agree with not dicking around testing parts from the after market carpet baggers...Simple really: Buy MOPAR parts.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
I'd almost bet Stant is licensed by Chrysler (and others) so there's a P'star stamp (maybe a GM and blue oval stamp also) at the Stant manufacturing plant where Stant makes the stat to Mopar's specs, part #'s and packaged in a box with the Mopar label.
Last edited by djb383; Oct 26, 2012 at 06:38 PM.


