Lower Temp 'Stat in LS3
Thread Starter
Drifting
Joined: Sep 2007
Posts: 1,331
Likes: 148
From: 1000 Islands Ontario
Lower Temp 'Stat in LS3
Hi.
Is it possible to install a 180 or 160 thermostat without reprogramming the ECU? I would think that if you did not tell the ECU, it would keep the fans off until the coolant was at the originally programmed temperature. Or, does the thermostat itself control the fans?
I would tend to go with a 180 'stat, ideally have the LS3 run in the upper 170's to mid 180's. Make sense?? This is all for mild street use - I just like to let it run a little cooler.
Where does one buy a reliable aftermarket thermostat for an LS3?
Thanks,
M.....
Is it possible to install a 180 or 160 thermostat without reprogramming the ECU? I would think that if you did not tell the ECU, it would keep the fans off until the coolant was at the originally programmed temperature. Or, does the thermostat itself control the fans?
I would tend to go with a 180 'stat, ideally have the LS3 run in the upper 170's to mid 180's. Make sense?? This is all for mild street use - I just like to let it run a little cooler.
Where does one buy a reliable aftermarket thermostat for an LS3?
Thanks,
M.....
Burning Brakes
Joined: Apr 2008
Posts: 815
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From: Virginia beach va
I put a 160 stat in my ls3 it runs about 180 right now before I put that in there it was around 200 but you can order them from forum vendors thats what I did. but I did reprogram my fans since I was getting the dyno tune done anyway.
Melting Slicks
Joined: May 2004
Posts: 3,017
Likes: 2
I just looked at mine. It say 86C on it or about 186F. If you change to a 160, your temps on the highway or any open cruising will be in the 175-180 range. Once you hit stopped traffic, with out fan reprogramming its going to go up over 195 in a hurry.
Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
But I'm assuming that what you're asking is if one might see the full benefits of a thermostat install even if you don't do the programming?
The answer is basically no, but installing a 160 degree thermostat all by itself can definitely still help lower one's coolant temps somewhat.
No the thermostat itself does not have any effect on fan operation/fan speeds. Only PCM programming can alter that.
Safety Car
Joined: Nov 2007
Posts: 4,537
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From: Bethesda MD
I drove mine for a bit before changing the fans. The 160 will lower temps when rolling without any changes to the programming. However, in town with stop and go, the temps will quickly climb to stock levels if the fans aren't changed.
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If you don't reprogram the fans, the t-stat change is not helpful. All it'll do is open the flow sooner but it is the air flowing through the radiator and the operation of the fans that controls the temperature. To get the benefits of the lower temp t-stat, you must reprogram the fans.
I prefer stock t-stat temp for fuel efficiency and sufficient temps to burn off the water in the oil. The guys that run it cooler are doing it to run better 1/4 mile times. If you run your car everyday in 1/4 mile spurts, it'll help you. Otherwise, it might not be the best idea for everyday driving. I have a stock t-stat in my Camaro with the twin turbos and it works just fine.
Elmer
I prefer stock t-stat temp for fuel efficiency and sufficient temps to burn off the water in the oil. The guys that run it cooler are doing it to run better 1/4 mile times. If you run your car everyday in 1/4 mile spurts, it'll help you. Otherwise, it might not be the best idea for everyday driving. I have a stock t-stat in my Camaro with the twin turbos and it works just fine.
Elmer
Safety Car
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From: Madison Wisconsin
St. Jude Donor '08
I have a 160 stat in my 08 and lately it's been running in the high 190's. It steadily climbs to 180 or so then slowly creeps up until it's running 199, 203, 205. And that is going at interstate speeds. I'm beginning to think it's sticking open. It has a Chcuk COW tune so the fans have been set already.
Melting Slicks
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From: merritt island fl
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I have a 160 stat in my 08 and lately it's been running in the high 190's. It steadily climbs to 180 or so then slowly creeps up until it's running 199, 203, 205. And that is going at interstate speeds. I'm beginning to think it's sticking open. It has a Chcuk COW tune so the fans have been set already.
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Safety Car
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From: CHOCOWINITY NC
A properly operating 160 stat in an LS3 should run right at 180 degrees actual (+/- a degree or 2). If you set the fans to ramp up from their starting temp to 90% at 200 degrees +, the car will stabilize at idle at 200 or less even on a hot day. With airflow while moving, 180. These temps are 15 to 20 degrees lower than the stock thermostat.
Safety Car
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From: Madison Wisconsin
St. Jude Donor '08
Safety Car
Joined: Mar 2005
Posts: 3,639
Likes: 8
From: Madison Wisconsin
St. Jude Donor '08
A properly operating 160 stat in an LS3 should run right at 180 degrees actual (+/- a degree or 2). If you set the fans to ramp up from their starting temp to 90% at 200 degrees +, the car will stabilize at idle at 200 or less even on a hot day. With airflow while moving, 180. These temps are 15 to 20 degrees lower than the stock thermostat.
Safety Car
Joined: Feb 2007
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From: CHOCOWINITY NC
Unfortunately, the accuracy and Manufacturers calibration of the typical thermostat seems pretty hit or miss. I have a Mr. Gasket that has worked fine from Day one. My buddy Zpirate ended up buying two of the same part number only to find both caused his car to run 20 degrees COOLER. Testing in a pot of boiling water confirmed the early opening problem. He ordered an SLP and now, on stat #3 his works just fine and just like mine. Don't rule out a bad thermostat (or maybe one that was never changed?). I doubt the gearing change makes a difference as I have 3:42's (MN6)and run around 2K when cruising back roads and temps are as described above
Safety Car
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From: Bethesda MD
Safety Car
Joined: Mar 2005
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From: Madison Wisconsin
St. Jude Donor '08
Sorry - don't mean to hijack the thread here. If it was stuck closed, it would be overheating big time. The fans are working fine. It used to work fine and run about 170 but for some reason it's now running near 200. I'm thinking the stat has gone bad.