160 thermostat
Thread Starter
Racer
Joined: Jun 2005
Posts: 275
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From: Pembroke NH
160 thermostat
I was wndering if anyone has some insight into this problem. I put in a 160 degree thermstat and a cooler fan switch on my 1984, in preparation of putting in a Hypertech chip. Now my water temp runs between 175-190. The over drive unit keeps kicking out after the fan lowers the temp below 180 (this was not a problem before I canged parts). Is there a way to adjust at what temp the over drive unit operates? Or do I install a on/off switch for the fan? Or will I run hotter when I install the chip?
Thanks
Thanks
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
I think that there is some issue with the 4+3 OD and coolant temp. You might IM Scrop508 as he too has a 4+3 and may be familiar with this issue along with a work around.
The HyperTech chip should just bring control the fan around the T-stat's 160deg setpoint.
Unless you are running the A/C, coolant temps should run no higher than 170s even in 90+ deg weather. You might pull the radiator shroud and see if the radiator needs cleaning.
The HyperTech chip should just bring control the fan around the T-stat's 160deg setpoint.
Unless you are running the A/C, coolant temps should run no higher than 170s even in 90+ deg weather. You might pull the radiator shroud and see if the radiator needs cleaning.
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by 65Z01
The HyperTech chip should just bring control the fan around the T-stat's 160deg setpoint.
Shortly thereafter, I realized what the too cool operating temps were doing to my engine. Sometimes, we simply "out smart" ourselves.
RACE ON!!!
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
The OD will not operate when the engine temp is below 125 F on my 87, it may be different for the 84. The ECM locks out the OD with temp info from the sensor at the front of the engine and your temp sensor might be sending the ECM a lower temp than shown on your dash.
Why did you install a 160 thermostat? From the temperatures you state, your 160 stat is wide open and is not regulating the coolant temperature. Your engine came with a 195 F thermostat and the radiator is sized to maintain that temperature when you are above 35 mph. Below 35 the cooling system gets some help from the electric fan and the coolant usually goes to 200-220 F but drops to 195 when you get underway. It isn't necessary to run lower than the GM designed 195 and in the summer the radiator isn't big enough to do it anyway. I would recommend you install the 195 stat.
Why did you install a 160 thermostat? From the temperatures you state, your 160 stat is wide open and is not regulating the coolant temperature. Your engine came with a 195 F thermostat and the radiator is sized to maintain that temperature when you are above 35 mph. Below 35 the cooling system gets some help from the electric fan and the coolant usually goes to 200-220 F but drops to 195 when you get underway. It isn't necessary to run lower than the GM designed 195 and in the summer the radiator isn't big enough to do it anyway. I would recommend you install the 195 stat.
Melting Slicks
Joined: Jul 2004
Posts: 2,018
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From: OR
Mine had a 160 when I got the car. Got 23.5 mpg like clock work for 10 months (per dash reading). Changed to 180 and immediately got 24.7 - 25 driving the same way the same route. Could be a coincidence I suppose.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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The coolant readings are good, don't worry about the thermostat.
But the fan switch has no control over the OD, and at those temps, neither does the ECM. If you install the chip to control the fan, you still shouldnt have a problem. My car has a 160 and I dont slip out of 4th (automatic), maybe the 4+3 has some quirk about it, but i've never heard of these being related.
But the fan switch has no control over the OD, and at those temps, neither does the ECM. If you install the chip to control the fan, you still shouldnt have a problem. My car has a 160 and I dont slip out of 4th (automatic), maybe the 4+3 has some quirk about it, but i've never heard of these being related.
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by vader86
If you install the chip to control the fan, you still shouldnt have a problem.
RACE ON!!!
Drifting
Joined: May 1999
Posts: 1,478
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From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
Originally Posted by kehler
... Now my water temp runs between 175-190. The over drive unit keeps kicking out after the fan lowers the temp below 180 (this was not a problem before I canged parts). Is there a way to adjust at what temp the over drive unit operates? Or do I install a on/off switch for the fan? Or will I run hotter when I install the chip?
I would NOT use a 160 thermostat if I was you. At least use a 180 (I do), or even go back to stock with a 195 as jfb recommends. If you are having cooling issues, pull and clean the radiator. The cooler fanswitch is a good idea as long as it isn't trying to bring the fans on (or the temps down) below 180.
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Thread Starter
Racer
Joined: Jun 2005
Posts: 275
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From: Pembroke NH
Thanks to all who posted on this question. I changed out the 160 for a 180 and left in the cooler thermostat switch. The overdrive now works again and my water temp stays right around 185 all the time. In addition I saved myself $150 by not going with the hyper chip, as it seems to be a waste of money. Thanks to all.
Race Director
Joined: May 2001
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Originally Posted by kehler
Thanks to all who posted on this question. I changed out the 160 for a 180 and left in the cooler thermostat switch. The overdrive now works again and my water temp stays right around 185 all the time. In addition I saved myself $150 by not going with the hyper chip, as it seems to be a waste of money. Thanks to all.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by Nathan Plemons
On a '93 auto I found a hypertech chip to adjust the TCC lockup, adjusted the fan temps and REMOVED THE REV LIMITER. Certainly a waste of money. All the timing and spark tables were the same.
RACE ON!!!