I finally got around to installing the 160 T-stat on my '93. It was Hypertech P/N 1011 from Summit.
Before I done this I managed some hands on time with the cooling system installing a manual over-ride for the cooling fan. I recorded the following results with the help of a infrared temperature gun:
N-
O-
R-215(Fan turns on)
M-200
A-180
L-160
With the manual over-ride on, I could cool the engine quickly from 205 or higher to 195 and it would stabilize at about 190(with the AC off).
Much has been said of the inherent pros and cons of a lower temperature thermostat and many suggested the 160 degree would be too low for optimum engine performance since the engine needed 180 degrees plus to be 'warmed up'. Since I had the stock thermostat(195?) and had shown a 'normal' operating temp of 205 plus, I surmised the engine would easily be 180 plus with the 160 T-stat. So I stuck with my original choice.
What a messy job this is! First, there is no way to cleanly drain the system. When the drain valve on the radiator is opened, coolant spews everywhere despite the best attempts to contain the stream. A normally large catch pan is suddenly too small in surface area. After the radiator had drained, I proceeded to attack the two bolts on the thermostat housing. Luckily I had an impact wrench and assorted extensions with a universal joint for the 10mm socket. Even with all that it was a PITA. With the bolts loose, a fresh stream of coolant cascades everywhere, so I drag the catch pan over and attempt to contain the mess as much as possible. To my suprise, another stream started again at the drain valve, so a mad dash to get yet another catch pan. Antifreeze is spewing out from under the car from one fender to the other! Good time for a break.
The next task was defying gravity in an attempt to stuff the new T-stat in the upper housing while positioning a new o-ring below it and somehow mangage to get them to stay while positioning the lower housing and starting the two bolts. Several futile attempts later, I enlisted the help of some permatex and finally got enough stickum on the T-stat and o-ring to stay long enough to get the bolts started. I torqued the bolts and then proceeded to fill the system.
Much to my dismay, after the reservoir was full and I was still filling the system at the crossover pipe, I discovered a steady drip of a leak at the thermostat housing. Turns out after close inspection, I had cut the o-ring as I could see about 1/4" of it sticking out from the housing. So I get to start all over! This time I use Caterpillar gasket cement to glue the new o-ring to the t-stat then a small bead of silcone to glue the t-stat in the upper housing. Luckily, I was at the shop at work, so things as new o-rings and such were no setback.
I filled the system as prescribed and thankfully there were no leaks. Monitoring with the temperature gun I could confirm the T-stat opening at approximately 160 degrees. Sitting idling with the A/C off, the engine temp was at 180 plus or minus. Turning on the A/C brought the temps up to 190-195. Road test time. Finding some nice long grades to power my way up, there was no fear of the t-stat being to cold. 215-220 was the temps when I parked in a nice hot asphalt parking lot. The temperature gun said 135 degrees at the pavement and the outside air temperature according to the EATC was 94 degrees. Turning on the manual over-ride for the cooling fan brought the temperature to 205-210 degrees in 3 minutes or so. After 10 minutes it seems to have stabilized at about 200, all the while the A/C keeping me at a cool 70 degrees.
After driving home, I turned off the A/C after pulling into the driveway and let the fan run high to see how long it would take to stabilize. After 5 minutes it had cooled to below 200 and I reached a stable 180 after another 5 minutes.
All in all I'm sastified with the new 160 degree thermostat and the manual over-ride of the cooling fan. Can't wait till the next track date to really check it out. The only thing I would like to add is an LED indicator of the fan status.
Before I done this I managed some hands on time with the cooling system installing a manual over-ride for the cooling fan. I recorded the following results with the help of a infrared temperature gun:
N-
O-
R-215(Fan turns on)
M-200
A-180
L-160
With the manual over-ride on, I could cool the engine quickly from 205 or higher to 195 and it would stabilize at about 190(with the AC off).
Much has been said of the inherent pros and cons of a lower temperature thermostat and many suggested the 160 degree would be too low for optimum engine performance since the engine needed 180 degrees plus to be 'warmed up'. Since I had the stock thermostat(195?) and had shown a 'normal' operating temp of 205 plus, I surmised the engine would easily be 180 plus with the 160 T-stat. So I stuck with my original choice.
What a messy job this is! First, there is no way to cleanly drain the system. When the drain valve on the radiator is opened, coolant spews everywhere despite the best attempts to contain the stream. A normally large catch pan is suddenly too small in surface area. After the radiator had drained, I proceeded to attack the two bolts on the thermostat housing. Luckily I had an impact wrench and assorted extensions with a universal joint for the 10mm socket. Even with all that it was a PITA. With the bolts loose, a fresh stream of coolant cascades everywhere, so I drag the catch pan over and attempt to contain the mess as much as possible. To my suprise, another stream started again at the drain valve, so a mad dash to get yet another catch pan. Antifreeze is spewing out from under the car from one fender to the other! Good time for a break.
The next task was defying gravity in an attempt to stuff the new T-stat in the upper housing while positioning a new o-ring below it and somehow mangage to get them to stay while positioning the lower housing and starting the two bolts. Several futile attempts later, I enlisted the help of some permatex and finally got enough stickum on the T-stat and o-ring to stay long enough to get the bolts started. I torqued the bolts and then proceeded to fill the system.
Much to my dismay, after the reservoir was full and I was still filling the system at the crossover pipe, I discovered a steady drip of a leak at the thermostat housing. Turns out after close inspection, I had cut the o-ring as I could see about 1/4" of it sticking out from the housing. So I get to start all over! This time I use Caterpillar gasket cement to glue the new o-ring to the t-stat then a small bead of silcone to glue the t-stat in the upper housing. Luckily, I was at the shop at work, so things as new o-rings and such were no setback.
I filled the system as prescribed and thankfully there were no leaks. Monitoring with the temperature gun I could confirm the T-stat opening at approximately 160 degrees. Sitting idling with the A/C off, the engine temp was at 180 plus or minus. Turning on the A/C brought the temps up to 190-195. Road test time. Finding some nice long grades to power my way up, there was no fear of the t-stat being to cold. 215-220 was the temps when I parked in a nice hot asphalt parking lot. The temperature gun said 135 degrees at the pavement and the outside air temperature according to the EATC was 94 degrees. Turning on the manual over-ride for the cooling fan brought the temperature to 205-210 degrees in 3 minutes or so. After 10 minutes it seems to have stabilized at about 200, all the while the A/C keeping me at a cool 70 degrees.
After driving home, I turned off the A/C after pulling into the driveway and let the fan run high to see how long it would take to stabilize. After 5 minutes it had cooled to below 200 and I reached a stable 180 after another 5 minutes.
All in all I'm sastified with the new 160 degree thermostat and the manual over-ride of the cooling fan. Can't wait till the next track date to really check it out. The only thing I would like to add is an LED indicator of the fan status.