67 GTX 440 Engine Temperature With AC

[67GTX440]

Not sure I like that recommendation. That assumes all senders and gauges, factory and aftermarket are interchangeable and you can't damage one or the other by crossing them. My repop gauge in the dash has always read low. A temp probe in the radiator confirms the aftermarket gauge reading.

 

[440+6]

One thing I don't think was mentioned is AC cars had different water pumps and a smaller pulley.
The ac pumps had 6 impellers vs 8 on non ac pumps.

The ac pumps actually moved less water but due to the smaller pulley ended up moving the same amount as the non ac setup, the benefit was the fan moving faster and pulling more air at all speeds.

Mixing these up can cause problems, small pulley and non ac pump can cause cavitation, large pulley with ac pump not enough flow

 

[67GTX440]

One thing I don't think was mentioned is AC cars had different water pumps and a smaller pulley.
The ac pumps had 6 impellers vs 8 on non ac pumps.

The ac pumps actually moved less water but due to the smaller pulley ended up moving the same amount as the non ac setup, the benefit was the fan moving faster and pulling more air at all speeds.

Mixing these up can cause problems, small pulley and non ac pump can cause cavitation, large pulley with ac pump not enough flow

Interesting. My new water pump had 6 impellers as compared to 8 on the one I removed and said it would flow 30% more water than OEM. I saw nothing about a non A/C verses A/C pump option when ordering the pump.

 

[Ranger16]

This should also tell me a 180 thermostat won't make it run any cooler than it does now without one.

The 180 or lower thermostat solving the problem theory should be pretty much disproved at this point.

The cooling time in radiator of the water may or may not have changed dependent on whether the thermostat or the radiator was the main flow restriction. Since the car is running 10-15 degrees cooler, I would say that the thermostat was the main point of flow restriction and more and faster flow through the radiator is the reason for the temp drop.

Still not sure I agree. In theory, the faster the coolant moves through the radiator, the less time it has to transfer heat. Personally, I don't think you are going to disprove that theory until you install a 180 or a 160 and see what happens. At this point, I'd go for the 160.

The more flow through the radiator from a higher flow fuel pump or removal of the thermostat causing less cooling time in the radiator and higher temperature should be disproved at this point, at least for my setup.

I assume you meant water pump?

 

[67GTX440]

Yeah, I meant water pump.

The 160 or 180 should open at that temperature and then remain open the same as the 195 did at 195. They may slightly delay the engine getting to its full open max temperature by opening sooner, but the end result with an open thermostat will be 210-215 degrees.

The full open 195 and the full open 160 will flow water through the radiator at the same rate. An open thermostat is an open thermostat. A 160 will not flow more or less when fully open than a 195.

It it obvious that the reduction of 10-15 degrees I got with no thermostat was as a result of better flow through the radiator - the lack of restriction from any thermostat at all. A 160 is going to go back to restricting flow and should result in the same 210-215 as the 195 once the thermostat is fully open and the water is circulating to max with max engine temperature being reached.

The 160 will open slightly sooner, but that gain will be lost quickly. An engine that runs at 210-215 with a 195 (the temp exceed the thermostat rating) will not run any cooler with a 160 or 180. Engine temp max is engine temp max on a long drive with the thermostat reaching full open.

Reaching 200 with no thermostat and reducing temp 10-15 degrees gives me no reason to try a 180 or 160 either one. Neither one should give any improvement if you think about it. The additional flow gave me a 10-15 temperature drop, and you are telling me to go back in and restrict the flow again.

I had a member on the site whose specialty is radiators and coolants PM me to try no thermostat and concurred that if that did not bring the temp down, no change in thermostat would. I am moving on to timing as a possible cause.

 

[Ranger16]

The full open 195 and the full open 160 will flow water through the radiator at the same rate. An open thermostat is an open thermostat. A 160 will not flow more or less when fully open than a 195.

I think you are over simplifying how a thermostat works.
This will explain the operation of a thermostat better than I can.
Per Wikipedia

"This most common modern form of thermostat now uses a wax pellet inside a sealed chamber. Rather than a liquid-vapor transition, these use a solid-liquid transition, which for waxes is accompanied by a large increase in volume. The wax is solid at low temperatures, and as the engine heats up, the wax melts and expands. The sealed chamber operates a rod which opens a valve when the operating temperature is exceeded. The operating temperature is fixed, but is determined by the specific composition of the wax, so thermostats of this type are available to maintain different temperatures, typically in the range of 70 to 90°C (160 to 200°F). Modern engines run hot, that is, over 80 °C (180 °F), in order to run more efficiently and to reduce the emission of pollutants.


While the thermostat is closed, there is no flow of coolant in the radiator loop, and coolant water is instead redirected through the engine, allowing it to warm up rapidly while also avoiding hot spots. The thermostat stays closed until the coolant temperature reaches the nominal thermostat opening temperature. The thermostat then progressively opens as the coolant temperature increases to the optimum operating temperature, increasing the coolant flow to the radiator. Once the optimum operating temperature is reached, the thermostat progressively increases or decreases its opening in response to temperature changes, dynamically balancing the coolant recirculation flow and coolant flow to the radiator to maintain the engine temperature in the optimum range as engine heat output, vehicle speed, and outside ambient temperature change. Under normal operating conditions the thermostat is open to about half of its stroke travel, so that it can open further or reduce its opening to react to changes in operating conditions. A correctly designed thermostat will never be fully open or fully closed while the engine is operating normally, or overheating or overcooling would occur."

 

[67GTX440]

I think you are over simplifying how a thermostat works.
This will explain the operation of a thermostat better than I can.
Per Wikipedia

"This most common modern form of thermostat now uses a wax pellet inside a sealed chamber. Rather than a liquid-vapor transition, these use a solid-liquid transition, which for waxes is accompanied by a large increase in volume. The wax is solid at low temperatures, and as the engine heats up, the wax melts and expands. The sealed chamber operates a rod which opens a valve when the operating temperature is exceeded. The operating temperature is fixed, but is determined by the specific composition of the wax, so thermostats of this type are available to maintain different temperatures, typically in the range of 70 to 90°C (160 to 200°F). Modern engines run hot, that is, over 80 °C (180 °F), in order to run more efficiently and to reduce the emission of pollutants.


While the thermostat is closed, there is no flow of coolant in the radiator loop, and coolant water is instead redirected through the engine, allowing it to warm up rapidly while also avoiding hot spots. The thermostat stays closed until the coolant temperature reaches the nominal thermostat opening temperature. The thermostat then progressively opens as the coolant temperature increases to the optimum operating temperature, increasing the coolant flow to the radiator. Once the optimum operating temperature is reached, the thermostat progressively increases or decreases its opening in response to temperature changes, dynamically balancing the coolant recirculation flow and coolant flow to the radiator to maintain the engine temperature in the optimum range as engine heat output, vehicle speed, and outside ambient temperature change. Under normal operating conditions the thermostat is open to about half of its stroke travel, so that it can open further or reduce its opening to react to changes in operating conditions. A correctly designed thermostat will never be fully open or fully closed while the engine is operating normally, or overheating or overcooling would occur."

Since I have the 180 Stant Superstat and gasket, I may as well throw it on and see what happens. The only thing that takes any time is the thermostat housing goo setting up for 24 hours before refilling and starting. I will give it a shot and report back. I would rather try that than go below what came out on the car originally. If it runs under 205, I will agree with your scenario.
I will report back, again. Stay tuned.

 

[67GTX440]

Since I have the 180 Stant Superstat and gasket, I may as well throw it on and see what happens. The only thing that takes any time is the thermostat housing goo setting up for 24 hours before refilling and starting. I will give it a shot and report back. I would rather try that than go below what came out on the car originally. If it runs under the 205 with no thermostat, I will agree with your scenario.
I will report back, again. Stay tuned.

 

[oldbee]

"67"- went to place where I used to work- 85deg. outside in Ohio(non a/c car)with a 160 T-stat.45-50mph for 15 miles.175 on my OEM gauge. Got caught at a light for 2 cycles and went up to 185-190. 26" Mishimoto radiator and everything else factory. If it were me with no boil over problems(& no cold winters) I would go with 160 stat and not worry. Everyone is correct, you need the restriction that the stat puts in the cooling loop. My old manual shows 6blade (w/pump)for an a/c car versus 8 for non.BUT, a 1.4-1 ratio pulley(a/c) versus .94-1 .. If yours is stock that should be all right.hood seal on almost all BB's..

 

[AR67GTX]

It sounds like you might be interested in trying a high flow thermostat. I've heard of them for awhile but never had a reason to try one. If no thermostat seems to help lower your max temperatures, they might suit your need.

http://www.motoradusa.com/techtip-high-flow-thermostats.aspx

 

[67GTX440]

It sounds like you might be interested in trying a high flow thermostat. I've heard of them for awhile but never had a reason to try one. If no thermostat seems to help lower your max temperatures, they might suit your need.

http://www.motoradusa.com/techtip-high-flow-thermostats.aspx

Aw Jeez! More options to try! More "is more flow good or is more flow bad discussion." There seem to be a real division of views with regard to higher flow water pumps and thermostats. I am trying stock 180 next.

 

[67GTX440]

It sounds like you might be interested in trying a high flow thermostat. I've heard of them for awhile but never had a reason to try one. If no thermostat seems to help lower your max temperatures, they might suit your need.

http://www.motoradusa.com/techtip-high-flow-thermostats.aspx

I may be interested in what you bought for an overflow bottle that seemed to fit the space (make, model and year) and cost. I did notice that after running no thermostat and filling radiator clear to the top, that it was still clear to the top after cycling hot and letting cool down. I would have expected some expansion when hot and contraction when cool, unless the contraction occurs somewhere other than the radiator with the thermostat removed.

 

[MarPar]

here's my overflow

 

[67GTX440]

That seems to work. Was it expensive? LOL

 

[MarPar]

That seems to work. Was it expensive? LOL

LOL it only cost me $8! and it came with free motor oil in the bottle to boot!

 

[TxDon]

I may be interested in what you bought for an overflow bottle that seemed to fit the space (make, model and year) and cost. I did notice that after running no thermostat and filling radiator clear to the top, that it was still clear to the top after cycling hot and letting cool down. I would have expected some expansion when hot and contraction when cool, unless the contraction occurs somewhere other than the radiator with the thermostat removed.

I think if you kept driving it it would puke at some point. I'd suggest a coolant recovery system instead of just an overflow bottle. I added this bottle from a 90s Subaru along with a vented cap, its now a sealed system where I can fill it to the top with no spills, that added at least 1/2 gallon of coolant. see my thread for more pics:
http://www.forbbodiesonly.com/moparforum/threads/67-gtx-texas-cooling-adventures.115664/

 

[MarPar]

Don, my overflow bottle is a "recovery tank" of sorts...ive seen where it has the little extra fluid I added into the bottle and suck it up once she's fully warmed up.

 

[Dennis H]

 

[Ranger16]

I would have expected some expansion when hot and contraction when cool, unless the contraction occurs somewhere other than the radiator with the thermostat removed.

Expansion and contraction occurs through the cooling system, but it shows in the radiator tank because that is the only place in the system that has air. Hard to imagine how it could be filled to the top, run up to operating temperature and not expand enough to puke some out. Perhaps you had some air in the system after removing the stat. That air then made it's way to the tank to give the coolant some head space for expansion and was vented as the coolant expanded. Only logical explanation I can think of.

 

[67GTX440]

I think if you kept driving it it would puke at some point. I'd suggest a coolant recovery system instead of just an overflow bottle. I added this bottle from a 90s Subaru along with a vented cap, its now a sealed system where I can fill it to the top with no spills, that added at least 1/2 gallon of coolant. see my thread for more pics:
http://www.forbbodiesonly.com/moparforum/threads/67-gtx-texas-cooling-adventures.115664/

View attachment 357517

Is this picture funny, or do your A/C compressor belts run at a pretty weird angle as compared to the water pump belt?