Cooling fan strategy on a 2020 XT4

[KrisZ]

There you go, active grill shatters looks like are the cause. You can try and see if they can be opened and closed by hand, carefully of course, maybe something is just stuck from dirt.

Beyond that, it’s dealer time since it’s got warranty.

 

[michaelluscher]

https://static.nhtsa.gov/odi/tsbs/2021/MC-10205561-9999.pdf

There's a TSB for a grille cover to prevent CAC icing in below 0° environments

What a hokey ahh solution from GM

Considering full warm up was often not being achieved, I'd have expected a full on MIL illumination, as wouldn't emissions be affected

 

[eljefino]

What a hokey answer from GM! Jeezum Christmas. The point of active grill shutters is that you wouldn't have to put one of those canvas grill covers on like you'd see on a 1980's school bus. So they want a grill cover for their grill cover, dawg. And you have to put it on and off manually every time the temp crosses the zero degree threshold.

Then they make it out of stretchy stuff that hooks into plastic with plastic, but the stretchy stuff has to be room temperature to work, so don't break anything when you take it off on a +5 degree day to prevent overheating.

I used to just shove cardboard up between my condenser and radiator, LOL. And that was on a s---box saturn.

 

[Thermo1223]

What a hokey answer from GM! Jeezum Christmas. The point of active grill shutters is that you wouldn't have to put one of those canvas grill covers on like you'd see on a 1980's school bus. So they want a grill cover for their grill cover, dawg. And you have to put it on and off manually every time the temp crosses the zero degree threshold.

Then they make it out of stretchy stuff that hooks into plastic with plastic, but the stretchy stuff has to be room temperature to work, so don't break anything when you take it off on a +5 degree day to prevent overheating.

I used to just shove cardboard up between my condenser and radiator, LOL. And that was on a s---box saturn.

Had to use these anytime below freezing if you wanted to keep heat in the engine while driving. Audi had problems with icing up inside the intercooler. So did newer TDI's. Luckily for MKIV's their intercooler was in the wheel well and never got a full blast of air.

A4 Jetta Winter Front

Front winter cover for an A4 Jetta. This cover reduces airflow to the radiator, helping the car warm up faster and stay warm. Custom made for IDParts. Includes both upper and lower grill covers. Ma...

www.idparts.com

 

[CapitalTruck]

So the theory is that when grill shutters malfunction it defaults to fans on full all the time to prevent overheating (in the event the shudders are stuck closed)? I would complain that “you could still let the engine warm up” before having the fans come on, but honestly, you can keep overheat events reduced by not allowing engine to warm up in the first place (hence fans directed to full on all the time). Like another commenter said, a check engine light would have been nice.

 

[CapitalTruck]

By the way, does that autel read transmission codes?

 

[dan_erickson]

So the theory is that when grill shutters malfunction it defaults to fans on full all the time to prevent overheating (in the event the shudders are stuck closed)? I would complain that “you could still let the engine warm up” before having the fans come on, but honestly, you can keep overheat events reduced by not allowing engine to warm up in the first place (hence fans directed to full on all the time). Like another commenter said, a check engine light would have been nice.

At work if we have a shutter unplugged it will run the fans at full blast until everything is reset

 

[michaelluscher]

By the way, does that autel read transmission codes?

Yes.

 

[MrHorspwer]

What a hokey answer from GM! Jeezum Christmas. The point of active grill shutters is that you wouldn't have to put one of those canvas grill covers on like you'd see on a 1980's school bus. So they want a grill cover for their grill cover, dawg. And you have to put it on and off manually every time the temp crosses the zero degree threshold.

Then they make it out of stretchy stuff that hooks into plastic with plastic, but the stretchy stuff has to be room temperature to work, so don't break anything when you take it off on a +5 degree day to prevent overheating.

I used to just shove cardboard up between my condenser and radiator, LOL. And that was on a s---box saturn.

The grill shutters don't cover the charge air cooler (intercooler), only the radiator. The TSB is for CAC icing. The CAC is the lower opening, where there is no shutter, not the large upper opening, where there is a shutter. The cover is only for the lower opening, not the upper.

Full size trucks with the 2.7L turbo and 3.0L diesel have upper and lower shutters: One fore the radiator and one for the CAC.

Like another commenter said, a check engine light would have been nice.

From the failure record posted earlier, it only set the fault once. Type B DTCs require two fault instances before illuminating the MIL.

 

[mk378]

Modern use of grille air shutters is for aerodynamics, not to regulate cooling of the engine.

 

[michaelluscher]

Modern use of grille air shutters is for aerodynamics, not to regulate cooling of the engine.

Considering it can 100% block the radiator, I find that hard to believe

It's main objective might be fuel economy, but it CAN severely affect cooling

 

[michaelluscher]

It took a few ounces, to bring it up to the middle seam of the coolant bottle
I fussed with the Autel some more, and I can bi directionally open and close the flaps

I cycled back and forth a few times, they seem to operate smoothly and completely
Maybe a transient price of twig/leaf or a piece of ice jammed them

C O M P U T E R S

It's humbling how much stuff can be learned/configured/reset

Cars these days

The amount of ignition cycles without malfunction is increasing, so it's healing

It's gonna get colder again soon, maybe it sticks cold

I'll monitor the situation, but nothing to lose sleep over

 

[tcp71]

F150s since 2015 have active shutters on the radiator grill. If you have an intercooler there is another set on that grill.

 

[Silverado12]

I hope you get your problem fixed. I just bought a 2023 XT4 Luxury AWD. Really nice car.

 

[michaelluscher]

F150s since 2015 have active shutters on the radiator grill. If you have an intercooler there is another set on that grill.

This particular vehicle only has one shutter over the radiator
The lower mounted CAC is unrestricted
But the Autel can recognize shutter #1 and shutter #2
Perhaps it's just how Autel does their software, or this GM PCM calibration is used for other power trains/platforms that have dual shutters

People laughed at me when I spent $350 on this Autel
...who's laughing now

 

[mk378]

It's main objective might be fuel economy, but it CAN severely affect cooling

That is the whole point, run closed as much as possible for better economy, but be able to open when needed should the engine get too hot.

 

[Gus_Mahn]

What a hokey answer from GM! Jeezum Christmas. The point of active grill shutters is that you wouldn't have to put one of those canvas grill covers on like you'd see on a 1980's school bus. So they want a grill cover for their grill cover, dawg. And you have to put it on and off manually every time the temp crosses the zero degree threshold.

Then they make it out of stretchy stuff that hooks into plastic with plastic, but the stretchy stuff has to be room temperature to work, so don't break anything when you take it off on a +5 degree day to prevent overheating.

I used to just shove cardboard up between my condenser and radiator, LOL. And that was on a s---box saturn.

They're there for fuel economy. It takes less horsepower to push air over the car than to push it through the radiator. The shudders are open anytime the ac compressor is running. I rebuilt a few salvage Cruzes with shudders. The shudder assemblies were very expensive to replace, and I learned how to disable/remove them without setting a code. If I had to guess, I'd say there was 1-2 mpg mpg improvement with the shudders on a 40+ mpg car. If you're in the snowbelt, Ice or snow can jamb the shudders, but Ive never seen it cause long term damage.

michaelluscher overall how do you like the XT4? We are thinking about getting one for my wife's next car. She liked the XT4 better than the Lexus's, we test drove. Before this issue, did it warm up quickly? She hates the cold and her current car has heat in a few blocks. A heated steering wheel will help, but she'll be unhappy if it takes a long time to warm up like the Cruzes did.

 

[Silverado12]

They're there for fuel economy. It takes less horsepower to push air over the car than to push it through the radiator. The shudders are open anytime the ac compressor is running. I rebuilt a few salvage Cruzes with shudders. The shudder assemblies were very expensive to replace, and I learned how to disable/remove them without setting a code. If I had to guess, I'd say there was 1-2 mpg mpg improvement with the shudders on a 40+ mpg car. If you're in the snowbelt, Ice or snow can jamb the shudders, but Ive never seen it cause long term damage.

michaelluscher overall how do you like the XT4? We are thinking about getting one for my wife's next car. She liked the XT4 better than the Lexus's, we test drove. Before this issue, did it warm up quickly? She hates the cold and her current car has heat in a few blocks. A heated steering wheel will help, but she'll be unhappy if it takes a long time to warm up like the Cruzes did.

I have a 2023 XT4 and it warms up quickly. I'm starting to get heat by the time I'm out of the subdivision which is about 1 mile.

 

[michaelluscher]

They're there for fuel economy. It takes less horsepower to push air over the car than to push it through the radiator. The shudders are open anytime the ac compressor is running. I rebuilt a few salvage Cruzes with shudders. The shudder assemblies were very expensive to replace, and I learned how to disable/remove them without setting a code. If I had to guess, I'd say there was 1-2 mpg mpg improvement with the shudders on a 40+ mpg car. If you're in the snowbelt, Ice or snow can jamb the shudders, but Ive never seen it cause long term damage.

michaelluscher overall how do you like the XT4? We are thinking about getting one for my wife's next car. She liked the XT4 better than the Lexus's, we test drove. Before this issue, did it warm up quickly? She hates the cold and her current car has heat in a few blocks. A heated steering wheel will help, but she'll be unhappy if it takes a long time to warm up like the Cruzes did.

When it's operating as it should, there's warmish air 2-3 minutes after cold start, say 35° OAT
The heated seats and steering wheel make you feel first class

 

[michaelluscher]

It's perfectly capable of getting and staying up to temp now
I think I know what happened
Ice/debris/malfunction of the grille shutters sent it into some kind of panic/default limp home mode, keeping the fan on full blast, blunting warm up and heat performance
Or, it's an intermittent issue (position sensor/motor) issue with the shutters, that only manifests in severely cold weather
I've been able to open and close the shutters with bidirectional control many times, with no issue
The coolant being 8oz low was unrelated IMO
I've finally got an appointment at the dealer (mid February )
I'll keep an eye on it, as temps have been moderate for this time of year (40° ), I'll mention it all to them when it's in
If it starts malfunctioning again in colder temps, that may agree with my hypothesis of intermittent shutter jamming

Edit: I just found a TSB
22-NA-094
Condition: Some customers may comment on a loss of cabin heat.
Cause: The cause of the condition may be a software anomaly in the engine control
module (ECM).
Correction: Reprogram the ECM.

It covers a lot of 2.0T LSY vehicles, and my build date XT4 falls into it

...GM, get it together

I'm just gonna walk in, and hand them the TSBs, let see how insulted they get