Modifying a 195 stat to 185
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Captain
Joined: Mar 2007
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Modifying a 195 stat to 185
After readingmany posts about installing a 180 stat, I did it and of course was one of the lucky ones to get the check engine light prize. I know the stat could be opening slightly lower than 180 and the temp sensor could be slightly off. I don't have the time to be swapping stats and sensors so the CEL doesn't come on.So does anyone know what size hole to drill in a 195 stat to make it around 185?
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Joined: Jul 2006
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From: Gainesville, Ga.
RE: Modifying a 195 stat to 185
are you getting the code ???? that says, taking too long to reach operating temperature, or something like that. thats common with a 160* or no thermostat, but not common with a 180*. i'm guessing you got a bad one, and its opening way before 180. by comparison, i just put in a 180, and drilled about a 1/8 - 3/16 hole in it according to a tip somewhere, and mine warms right up with no code.
did you test the thermostat on the kitchen stove. its a good idea to always do that. put it in a pot of water and turn it on high. hang a meat thermometer over in the water, and see where it opens. my new one opened up at 180 on the nose, and my old one opened at 195. pull out your new one and test it and see what its doing.
did you test the thermostat on the kitchen stove. its a good idea to always do that. put it in a pot of water and turn it on high. hang a meat thermometer over in the water, and see where it opens. my new one opened up at 180 on the nose, and my old one opened at 195. pull out your new one and test it and see what its doing.
Champion
Joined: Aug 2005
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RE: Modifying a 195 stat to 185
Drilling a hole does not turn a 195 into a 180.
Hole drilling is normally used on older engines that originally had bypass around the thermostat that a racer has blocked off. The 5.2/5.9 V8 is of this design, but the newer 5.7 Hemi is not.
A 3/16ths hole is then normally drilled so that at least some coolant flows when the engine is cold and its bypass has been blocked. This small amount of flow is important so that the temperature sensor reads correctly, and to let steam bubbles pass out to the empty space above the coolant inside the radiator.
Increasing the hole to 3/8ths or 1/2 might cause the coolant to stay at 180 during 'daily driving' but you would still get the CEL because it gets set when the coolant does not get to 147 degrees fast enough after a cold start to satisfy the PCM computer internal timer.
I have placed a 17 mm socket with a 3/8ths square drive opening inside my short bypass hose as a 'restrictor' to force more coolant through the radiator at full throttle. I have run 195, 205, 180 and no thermostat.
My reading have found that when you go to full throttle on a 5.9/5.2 V8 the coolant almost immediately goes to about 205 degrees. That is all that the standard radiator can cool the coolant to.
It is important to realise that the thermostat's function is to 'hold' a minimum low temperature.
It is important to realise that it is the job of the pump, radiator and fan to limit the high temperature the coolant gets to.
If you want to keep the coolant at 180 degrees during full throttle you need to swap in a V10 size radiator along with the lower temperature thermostat,
or drive only when the air temperature outside is less than 40 degrees.
Hole drilling is normally used on older engines that originally had bypass around the thermostat that a racer has blocked off. The 5.2/5.9 V8 is of this design, but the newer 5.7 Hemi is not.
A 3/16ths hole is then normally drilled so that at least some coolant flows when the engine is cold and its bypass has been blocked. This small amount of flow is important so that the temperature sensor reads correctly, and to let steam bubbles pass out to the empty space above the coolant inside the radiator.
Increasing the hole to 3/8ths or 1/2 might cause the coolant to stay at 180 during 'daily driving' but you would still get the CEL because it gets set when the coolant does not get to 147 degrees fast enough after a cold start to satisfy the PCM computer internal timer.
I have placed a 17 mm socket with a 3/8ths square drive opening inside my short bypass hose as a 'restrictor' to force more coolant through the radiator at full throttle. I have run 195, 205, 180 and no thermostat.
My reading have found that when you go to full throttle on a 5.9/5.2 V8 the coolant almost immediately goes to about 205 degrees. That is all that the standard radiator can cool the coolant to.
It is important to realise that the thermostat's function is to 'hold' a minimum low temperature.
It is important to realise that it is the job of the pump, radiator and fan to limit the high temperature the coolant gets to.
If you want to keep the coolant at 180 degrees during full throttle you need to swap in a V10 size radiator along with the lower temperature thermostat,
or drive only when the air temperature outside is less than 40 degrees.