I have a question about the active grille shuttters on our 2017 GMC Acadia. I know why they are there: faster engine warm up, lower emissions, decreased air drag by forcing air over the hood, etc. Could it also cause higher automatic transmission temps since it’s blocking air flow to the radiator when traveling on the highway? We were on a 200 mile trip recently and noticed the transmission temperature was reading 207 degrees about 100 miles into our trip. A little background: I was driving 70 mph, flat terrain, just the wife and I, outside temperature 101 degrees (yes it gets hot in Texas), air conditioner working good, engine temperature normal. We had to make a 250 mile trip about two weeks later. Same background as before but we left at 5:00 am in the morning and when reached our destination the outside temperature was around 85-90 degrees and the transmission temperature peaked at 194 at that time. I talked to the dealer about the 207 degree temperature and was told it was normal and not to worry about it. Sorry for the long rant. What do you guys think?
Active Grille Shutters
- Thread starter Berny
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Sure they will cause higher temps if they block any air flow at all, transmission coolers need air flow in hot weather and in winter a thermostat to maintain operating temp, too hot or cold is not optimal.
Not being familiar with them on this vehicle I suspect in hot temps they are wide open and offer little restriction.
If not they would find themselves in the bin real quick.
Not being familiar with them on this vehicle I suspect in hot temps they are wide open and offer little restriction.
If not they would find themselves in the bin real quick.
In a perpetually warm climate I would probably remove them. That said, there should be temperature/speed parameters for when they open. *guessing* that stopped in traffic with the fan on the shutters would open, but on the highway enough airflow is coming through the upper grill area.
I have a buddy with a Focus ST with the active shutters. I'm pretty sure if the A/C is on they are open. Are you sure they were closed when driving on the highway with the A/C on? 207 on a 101 degree day doesn't sound bad to me.
I have a buddy with a Focus ST with the active shutters. I'm pretty sure if the A/C is on they are open. Are you sure they were closed when driving on the highway with the A/C on? 207 on a 101 degree day doesn't sound bad to me.
Here is the description of operation:
Active Grille Air Shutter Description and Operation
The active grille air shutter system closes shutters in the front grille to enhance vehicle aerodynamics in driving situations where cooling and A/C loads are relatively low and high levels of front end airflow are not required. If high levels of airflow are required the active grille air shutter system will open one or both shutters. The control signal from the engine control module, ignition and ground circuits enable the active grille air shutter actuators to operate. If the conditions for opening the shutters are reached the engine control module commands the active grille air shutter actuators to open one or both shutters.
The dual active grille air shutter system consists of two aero shutter mechanisms located in the front grille for controlling the amount of air flowing through the grille. It includes three wires; ground, power and a Local Interconnect Network (LIN) Bus serial data circuit from the engine control module to the shutter actuator. The engine control module determines shutter state based on various vehicle conditions such as vehicle speed, coolant temperature, fan state, refrigerant system pressure, A/C compressor state and ambient temperature. The engine control module has the ability to command each shutter individually to the open or closed positions through communications on the LIN Bus.
The actuators are powered by an ignition circuit that is active when the key is in the RUN position. The vehicle may have to be driven for up to 13 minutes at speeds greater than 41km/h (25mph) before a shutter begins to move. If low ambient temperature is detected, the shutters will remain in the closed position.
Active Grille Air Shutter Description and Operation
The active grille air shutter system closes shutters in the front grille to enhance vehicle aerodynamics in driving situations where cooling and A/C loads are relatively low and high levels of front end airflow are not required. If high levels of airflow are required the active grille air shutter system will open one or both shutters. The control signal from the engine control module, ignition and ground circuits enable the active grille air shutter actuators to operate. If the conditions for opening the shutters are reached the engine control module commands the active grille air shutter actuators to open one or both shutters.
The dual active grille air shutter system consists of two aero shutter mechanisms located in the front grille for controlling the amount of air flowing through the grille. It includes three wires; ground, power and a Local Interconnect Network (LIN) Bus serial data circuit from the engine control module to the shutter actuator. The engine control module determines shutter state based on various vehicle conditions such as vehicle speed, coolant temperature, fan state, refrigerant system pressure, A/C compressor state and ambient temperature. The engine control module has the ability to command each shutter individually to the open or closed positions through communications on the LIN Bus.
The actuators are powered by an ignition circuit that is active when the key is in the RUN position. The vehicle may have to be driven for up to 13 minutes at speeds greater than 41km/h (25mph) before a shutter begins to move. If low ambient temperature is detected, the shutters will remain in the closed position.
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I can tell you for a fact that 207* transmission temps are not good, especially when you aren't towing or pulling a load. There was a sheet that used to be spread around showing that trans fluid begins degrading and transmission life shortens greatly anytime the fluid exceeds 200*F. I can tell you this, my 05 F350 which often tows 12,000lb plus in the Florida heat NEVER sees over 180* trans fluid temps.
Sounds like another "CAFE rules over durability" thing to me... I'd take them out most definitely if you live in a hot climate!
Sounds like another "CAFE rules over durability" thing to me... I'd take them out most definitely if you live in a hot climate!
Originally Posted By: racin4ds
I can tell you for a fact that 207* transmission temps are not good, especially when you aren't towing or pulling a load. There was a sheet that used to be spread around showing that trans fluid begins degrading and transmission life shortens greatly anytime the fluid exceeds 200*F. I can tell you this, my 05 F350 which often tows 12,000lb plus in the Florida heat NEVER sees over 180* trans fluid temps.
Sounds like another "CAFE rules over durability" thing to me... I'd take them out most definitely if you live in a hot climate!
What kind of trans cooler is on your F350? Is there an auger that feeds ice from the bed to a cooler the size of a VW beetle?
But really that sounds like some serious cooling towing that weight. Most stock coolers on SUVs I've seen keep temps around 200F. Might not be ideal but they're pretty dinky coolers to begin with. My 97 Jeep has a larger factory cooler than my 16' Frontier.
EDIT: From some of the quick "research" i've done, it looks like the Acadia with the factory tow package has a slightly upgraded radiator, but the trans cooler is in the Rad. So it probably stands to reason that if the Rad hits 200 or so, the trans will to. It sounds like its not a separate cooler. Can you confirm Berny?
I can tell you for a fact that 207* transmission temps are not good, especially when you aren't towing or pulling a load. There was a sheet that used to be spread around showing that trans fluid begins degrading and transmission life shortens greatly anytime the fluid exceeds 200*F. I can tell you this, my 05 F350 which often tows 12,000lb plus in the Florida heat NEVER sees over 180* trans fluid temps.
Sounds like another "CAFE rules over durability" thing to me... I'd take them out most definitely if you live in a hot climate!
What kind of trans cooler is on your F350? Is there an auger that feeds ice from the bed to a cooler the size of a VW beetle?
But really that sounds like some serious cooling towing that weight. Most stock coolers on SUVs I've seen keep temps around 200F. Might not be ideal but they're pretty dinky coolers to begin with. My 97 Jeep has a larger factory cooler than my 16' Frontier.
EDIT: From some of the quick "research" i've done, it looks like the Acadia with the factory tow package has a slightly upgraded radiator, but the trans cooler is in the Rad. So it probably stands to reason that if the Rad hits 200 or so, the trans will to. It sounds like its not a separate cooler. Can you confirm Berny?
I doubt 207F is a problem. This modern car is computer controlled. It knows the ambient temp, the fluid temp, the speed of the car, throttle position and controls and tracks the position of the shutters. Transmission fluids are partly synthetic these days. I wouldn't worry about it.
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Is there a thermostat in the transmission cooler loop? Newer F150s have one that don't fully open until fluid temps runs just above 200. I would imagine it might be something similar here.
You are ok, at 207F you just need to change your ATF sooner compared to if it were at 175F.
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These are the control parameters for the 2.0L EcoBoost engine in my 2017 Edge Titanium.
Inputs/outputs used for controlling the active grille shutter system are the:
Engine Coolant Temperature (ECT) sensor
Intake Air Temperature (IAT) sensor
A/C pressure transducer
Accelerator Pedal Position (APP) sensor
ABS module, messages sent over the High Speed Controller Area Network (HS-CAN)
Engine cooling fan motor
Engine oil temperature
Inputs/outputs used for controlling the active grille shutter system are the:
Engine Coolant Temperature (ECT) sensor
Intake Air Temperature (IAT) sensor
A/C pressure transducer
Accelerator Pedal Position (APP) sensor
ABS module, messages sent over the High Speed Controller Area Network (HS-CAN)
Engine cooling fan motor
Engine oil temperature
I would think hat since the tranny cooler is at the bottom of the rad that the louvres even if closed would not effect that part.
I don't really see the purpose of these in a gas engines, with all the [censored] on the motor this one get warmed up pretty quickly, as an improvement for air flow I can't see what a slab perpendicular to the street would add, but rather an obstruction to create more resistance. On a diesel yes as these must be warmed up to give the best performance. I still prefer the old "Mask" at least I know when it's working and when not. Don't trust sensors any more than I have to.
I don't really see the purpose of these in a gas engines, with all the [censored] on the motor this one get warmed up pretty quickly, as an improvement for air flow I can't see what a slab perpendicular to the street would add, but rather an obstruction to create more resistance. On a diesel yes as these must be warmed up to give the best performance. I still prefer the old "Mask" at least I know when it's working and when not. Don't trust sensors any more than I have to.
This is so outdated. Ford's 6r80 and now 10r80 transmissions from 2009 onward have a thermostat inside that doesn't even flow any through the cooler until 190f. 207f is fine for a modern LV or ULV transmission fluid. An 05 f350 probably still uses Mercon 5 and has isn't pertinent to this conversation.
Originally Posted By: MarkM66
http://www.tciauto.com/tc/trans-life-expectancy/
Originally Posted By: MarkM66
http://www.tciauto.com/tc/trans-life-expectancy/
There is no separate cooler except for the one in the radiator. It does not have the towing package but according to the owners manual it can tow up to 1000 lbs. I wonder what the temperature would have been if we had four adults riding with us at the time. This is our first car with a transmission temperature indicator and I was a little concerned when I scrolled through Driver Information Center and saw the 207. I've always changed the transmission fluids around 50K and use Valvoline Dexron full synthetic. I guess I'll have to do it sooner now. Thanks for all the replies.
Was going to say, that's an old chart.
A number of cars use an in-radiator heat exchanger; my truck doesn't but it still sends coolant to the side of the transmission so as to set up an heat exchanger with the transmission. IOW, the OEM's are perfectly happy if the ATF is the same temperature as the coolant, at least on some setups.
I like the idea of active shutters but I bet the luddite in me would hate to repair one.
A number of cars use an in-radiator heat exchanger; my truck doesn't but it still sends coolant to the side of the transmission so as to set up an heat exchanger with the transmission. IOW, the OEM's are perfectly happy if the ATF is the same temperature as the coolant, at least on some setups.
I like the idea of active shutters but I bet the luddite in me would hate to repair one.
Originally Posted By: Berny
There is no separate cooler except for the one in the radiator. It does not have the towing package but according to the owners manual it can tow up to 1000 lbs. I wonder what the temperature would have been if we had four adults riding with us at the time. This is our first car with a transmission temperature indicator and I was a little concerned when I scrolled through Driver Information Center and saw the 207. I've always changed the transmission fluids around 50K and use Valvoline Dexron full synthetic. I guess I'll have to do it sooner now. Thanks for all the replies.
I wouldn't worry. Change every 50k, that is what I'd do, and not think much of it.
If you are ever worried about it, when under a load, just look at the tach, and force downshifts if rpm isn't above 2-3k. OEM's are better these days, especially with six plus speeds in the transmissions; but back in the bad old days, they'd just unlock the torque convertor for a few extra rpm. The extra slippage would heat fluid and quickly. I doubt it's a problem today, but if you can tell when the convertor is unlocked, force a downshift and that might encourage lockup, and that will control heat. Even if it won't lock up, at higher rpm slippage is minimized.
There is no separate cooler except for the one in the radiator. It does not have the towing package but according to the owners manual it can tow up to 1000 lbs. I wonder what the temperature would have been if we had four adults riding with us at the time. This is our first car with a transmission temperature indicator and I was a little concerned when I scrolled through Driver Information Center and saw the 207. I've always changed the transmission fluids around 50K and use Valvoline Dexron full synthetic. I guess I'll have to do it sooner now. Thanks for all the replies.
I wouldn't worry. Change every 50k, that is what I'd do, and not think much of it.
If you are ever worried about it, when under a load, just look at the tach, and force downshifts if rpm isn't above 2-3k. OEM's are better these days, especially with six plus speeds in the transmissions; but back in the bad old days, they'd just unlock the torque convertor for a few extra rpm. The extra slippage would heat fluid and quickly. I doubt it's a problem today, but if you can tell when the convertor is unlocked, force a downshift and that might encourage lockup, and that will control heat. Even if it won't lock up, at higher rpm slippage is minimized.
This sounds like having too much information available. Kinda like how they got rid of "real" oil pressure gauges and deadened the heck out of the coolant temp needle.
My wife's old HHR was way less sophisticated but even it knew when it was overheating due to a dud rad fan motor. It beeped at me (!) and shut off the AC. Yours would know how the trans fluid was doing and start doing stuff like making firmer shifts and more TCC lockup to cool it down, before/while alerting you outright via DIC.
That beeping legit saved the motor, as the deadened gauge never did anything interesting and I mostly ignored it.
My wife's old HHR was way less sophisticated but even it knew when it was overheating due to a dud rad fan motor. It beeped at me (!) and shut off the AC. Yours would know how the trans fluid was doing and start doing stuff like making firmer shifts and more TCC lockup to cool it down, before/while alerting you outright via DIC.
That beeping legit saved the motor, as the deadened gauge never did anything interesting and I mostly ignored it.
The reality is that we have no idea why the trans temp was higher. I know it's a forum board and the idea is discussion but to single out a feature without knowing the other numerous variables could be a case of connecting dots that aren't even on the same page.
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