Performance loss with 180 degree thermostat??
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From: Endwell, NY

Hello Everyone,
I installed a 180 degree thermostat over the weekend. I have noticed a slight loss in performance. The 195 thermostat was just fine in the car. It ran at 195-200 degree'*. Now with the 180 degree in the car it does run cooler which is great. I can deal with the loss of performance, id rather have the car run cooler. I was just wondering if anyone else has noticed the same loss of power?? It'* not a major loss but, there is a loss..
Thank you,
Sellncars
I installed a 180 degree thermostat over the weekend. I have noticed a slight loss in performance. The 195 thermostat was just fine in the car. It ran at 195-200 degree'*. Now with the 180 degree in the car it does run cooler which is great. I can deal with the loss of performance, id rather have the car run cooler. I was just wondering if anyone else has noticed the same loss of power?? It'* not a major loss but, there is a loss..
Thank you,
Sellncars
That is odd? The 180* tstat does not make the car run cooler for the most part but makes the car take longer to heat up? Are you aware of the closed loop or open loop operation of a modern pcm? I suspect you did not give it ample time for the pcm to take over air/fuel managment or perhaps you have the wrong tstat?
Thread Starter
Senior Member
Posts like a Supercharger
Joined: Apr 2004
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From: Endwell, NY

Originally Posted by PontiacDad
That is odd? The 180* tstat does not make the car run cooler for the most part but makes the car take longer to heat up? Are you aware of the closed loop or open loop operation of a modern pcm? I suspect you did not give it ample time for the pcm to take over air/fuel managment or perhaps you have the wrong tstat?
Yes i'am sure it is a 180 degree T-Stat. The car runs at or near 180 degree'* now. Before it would run at or near 200 which i was NOT worried about. I put the T-Stat in on Thursday actually. I drove the car all weekend long so i'am sure by now that the Computer would have straightened itself out. The car runs great and cooler. Just feels like it has less throttle responce then it had before. I guess the only way to be sure is to put in the old T-Stat which i kept, so that i could change it for the winter month'*. Yes i did use a new gasket with the Stat. It'* not worth messin around for less the $1.00..
Thanks,
Sellncars
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From: Westerville, Ohio 2000 Black SSEi

Your 180 T-stat should not make the car cooler in town without either a manual fan turn on, or a change in the computers programming on when to kick the fan on. It will open sooner allowing coolant to flow earlier to help keep it cool and it will do so at highway speeds where the wind can cool the coolant in the rad. I would expect to see 180 degree at 55+ mph and your nomral 200 or so in town where there is no aif flow.
As for performance loss, i would expect maybe a slight drop in fuel economy but not in power. Are you sure you didnt disconnect an IAT sensor, or coolant temp sensor or something else when you changed it? Did you bleed the system after the install? If not you may have some air trapped in the cooling system.
As for performance loss, i would expect maybe a slight drop in fuel economy but not in power. Are you sure you didnt disconnect an IAT sensor, or coolant temp sensor or something else when you changed it? Did you bleed the system after the install? If not you may have some air trapped in the cooling system.
Originally Posted by Rogue
Your 180 T-stat should not make the car cooler in town without either a manual fan turn on, or a change in the computers programming on when to kick the fan on. It will open sooner allowing coolant to flow earlier to help keep it cool and it will do so at highway speeds where the wind can cool the coolant in the rad. I would expect to see 180 degree at 55+ mph and your nomral 200 or so in town where there is no aif flow.
Rogue is dead on. The 180° only really makes a difference in the first 5 minutes of running, and on the freeway where there'* plenty of airflow. On a typical summer day around town, it really makes no difference.
A point I'd like to add is that a drilled thermostat can be of benefit, even if the thermostat is above 180° and open. It still allows just a wee bit more circulation that doesn't have to move 'around' the seat of the stat.
A point I'd like to add is that a drilled thermostat can be of benefit, even if the thermostat is above 180° and open. It still allows just a wee bit more circulation that doesn't have to move 'around' the seat of the stat.


