Recall and mileage

[Weird Harold]

I have an XLT Hybrid, and like everyone else, I got the recall for possible engine fire, requiring drain holes in the shield and removal of two of the active shutters. I have noticed that my gas mileage seems to have gone down since the removal of the shutters. Has anyone else seen this? Took a road trip to Chicago area last week and I also noticed that the operating temperature never got very far up the temp gauge, staying just about 25%. This is not scientific in any way, but every other car I've ever owned, in normal highway driving the temperature gauge settles somewhere in the middle of the gauge.
Yes, I know it is winter, and gas mileage takes a hit in cold weather, but has anyone else noticed a mileage drop after having the recall done?
I am considering trying to have one of the shutters put back. It seems to me that there is so much airflow with the shutters removed that the engine never gets up to normal operating temperature in cold weather. I'm curious whether other hybrid owners have had the same experience?

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[Hotwheels]

My mileage has gone down post recall service. It’s hard to say if the recall has any impact for me because of the cold and running on snow tires.

 

[jsus]

There are two modifications.

1) Holes in the aero cover under the engine, which should have negligible impact on fuel economy.

2) Removal of a small portion (25%?) of the AGS vanes. The system as a whole likely only accounts for a 1-2% fuel efficiency improvement. While this will cause a small hit, it's under 1 mpg.

Source - Society of Automotive Engineers (SAE): https://www.sae.org/publications/technical-papers/content/2022-01-5013/

Likely you're just seeing the affects of the cold. Check your tire pressures as well.

On your trip to Chicago, if that was not at freeway speeds but rather lower speeds where the hybrid could cycle the engine off and on frequently, the engine will not necessarily reach the middle of the gauge. That's just wasted heat energy unless the engine is needed full time.

 

[Dad]

Have not noticed any drop in mileage since the recall "fix". Doesn't get that cold here in SoCal, so I cannot factor that in to mine. I usually get 45-50 mpg on highway runs of over 5 miles.

 

[Catmandu]

Mine declined after the recall fix too... but it has been substatially colder. And like others snow tires are on. As Jsus noted these are relatively minor changes and highly unlikely its related to the decline. That said I'm reserving a final call on this until next summer, when I can see if my MPGs return to my previous summer #'s

 

[Renho17]

My operating temp gets up to the middle on hwy. so not seeing what ur seeing.

 

[2022EOW]

My mileage has gone down post recall service. It’s hard to say if the recall has any impact for me because of the cold and running on snow tires.

I have an XLT Hybrid, and like everyone else, I got the recall for possible engine fire, requiring drain holes in the shield and removal of two of the active shutters. I have noticed that my gas mileage seems to have gone down since the removal of the shutters. Has anyone else seen this? Took a road trip to Chicago area last week and I also noticed that the operating temperature never got very far up the temp gauge, staying just about 25%. This is not scientific in any way, but every other car I've ever owned, in normal highway driving the temperature gauge settles somewhere in the middle of the gauge.
Yes, I know it is winter, and gas mileage takes a hit in cold weather, but has anyone else noticed a mileage drop after having the recall done?
I am considering trying to have one of the shutters put back. It seems to me that there is so much airflow with the shutters removed that the engine never gets up to normal operating temperature in cold weather. I'm curious whether other hybrid owners have had the same experience?

I saw no difference after the recall fix which was done in the Fall. Cold weather on the other hand has a major impact. Add snow tires with less rolling resistance and it will noticeably drop more.

 

[Scupking]

Mine was done at the dealer before I could take delivery back in August. I was averaging 41.5mpg in the summer. Now that it's winter I'm at 36mpg. For me it seems about what this truck should be getting.

 

[JimParker256]

I saw no difference after the recall fix which was done in the Fall. Cold weather on the other hand has a major impact. Add snow tires with less rolling resistance and it will noticeably drop more.

I live in Texas, so I have zero experience with snow tires, but have been purchasing "low rolling resistance" tires for my previous ride (Prius-C) under the (possibly mistaken) belief that low rolling resistance meant better gas mileage. Hoping I'm not wrong on that...

I thought that the mileage issue with snow tires is that they have higher rolling resistance than regular tires due to softer sidewalls and different rubber formulations to remain pliable in cold weather? It would make sense to me that greater rolling resistance would mean more power is required from the powertrain to reach/maintain a given speed, which would mean more fuel required, right? I'm confused.

 

[jsus]

I live in Texas, so I have zero experience with snow tires, but have been purchasing "low rolling resistance" tires for my previous ride (Prius-C) under the (possibly mistaken) belief that low rolling resistance meant better gas mileage. Hoping I'm not wrong on that...

I thought that the mileage issue with snow tires is that they have higher rolling resistance than regular tires due to softer sidewalls and different rubber formulations to remain pliable in cold weather? It would make sense to me that greater rolling resistance would mean more power is required from the powertrain to reach/maintain a given speed, which would mean more fuel required, right? I'm confused.

No, you've got it right.

Rolling resistance is a type of friction that occurs when a tire rolls against pavement. Therefore, LRR tires reduce friction, meaning it takes less energy to roll the tire down the road, thus it's more efficient.

In the process and as a direct consequence of reducing rolling resistance, you also reduce traction, also known as grip. The tires roll more easily as they simply have less grip on the road.

Winter tires are the opposite. They exist to increase your rolling resistance as a consequence of increasing traction at lower temperatures.

Think about it this way. An all-season (or worse, summer/performance) tire will be more prone to sliding than rolling on ice. Why? A lack of traction. To fix that, winter tires do a better job of gripping the pavement, allowing them to roll instead of sliding.

That added grip does come at a cost. Most of the time, unless you're in particularly cold/snowy/icy and remote areas, the pavement will actually be clear of snow and ice. An all-season tire would generally have plenty of grip for this, say in a metro area in Ohio. That increased traction means increased rolling resistance over those all-seasons, thus increased rolling resistance and reduced fuel economy. After all, you're not going to swap your winter tires on only when there's snow and ice currently on the roads; they stay on all winter. In the end, it's worth taking a bit of a fuel economy hit for the increased traction, especially as there are times the roads are dicier than you'd expect. Better to be prepared.

Long story short, winter tires have more RR than all-seasons, which have more RR than low RR tires.

Note that this assumes that it's cold enough outside for winter tires. Once it warms up, they become much softer, reducing rolling resistance. They are not fit for use outside of winter.

https://en.wikipedia.org/wiki/Rolling_resistance

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