Big fuel economy drop after changing from synblend to full synthetic???

[Ignatius]

STORY TIME! So a company recruited me to come work for them and I received a low mileage 2021 Ford Bronco Sport as my work vehicle. This vehicle has the 1.5L Dragon 3-cylinder Ecoboost engine with dual injection. Maintenance history is that the FF was changed back in December 2021 after 9300 miles or so. The company has a contract with Valvoline Instant Oil Change to have basic maintenance services performed there.

At the time that I inherited this vehicle it had another 9300 additional miles on it since it's last oil change which happened to be using Valvoline 5W20 synblend. So twice it has been run to approx 9300 miles on a synblend. What I did notice before I got this most recent oil change between the 18000-19000 mile mark was that vehicle was getting what I would consider to be exceptionally good gas mileage, averaging 33-34 MPG per tank while most others are get mid-20's MPG for fuel economy.

Since I got the oil changed to Valvoline Full Synthetic Maxlife 5w20 (that's what VIOC put in when I told them I wanted full synthetic this time) the fuel economy has since dropped to 25-26 MPG.

I have similar driving patterns every single day which is primarily at highway speeds and I drive at or slightly above the speed limit and usually in normal or economy mode in an attempt to maximize fuel economy. Other variables to consider are that the weather is improving as far as temperatures go and tires are at recommended pressure.

I want to know what the honorable.members of BITOG think about this one

 

[pbm]

Hard to figure this out....even if the VIOC used 5w30 by mistake I can't see it causing such a big drop in MPG.

 

[Danimal1q2w3]

I think you have a couple tanks of gas as your sample size and it’s too small to mean anything, respectfully

 

[Kira]

For the first and second 9,300 mile stints, you weren't the driver, correct?
How long have YOU been monitoring the fuel use? I'm thinking small sample size too.

BP/Shell/Amaco/Sunoco premium to Whattzitt Matta regular could account for some of your disappointment.
Has your region switched to "Summer blend" yet?

 

[Graham Piccinini]

I had a large MPG drop once with Valvoline oils.
2003-2008 Toyota 1.8L (1ZZ-FE) VVT-i engine. Used syn-blend MaxLife 5W30/10W30/10W40 a handful of times with great results in that previously neglected vehicle. One day tried Valvoline MST 5W40 and fuel consumption numbers (hand calculated) went from 29MPG average to 24MPG average, and vehicle felt like it was tugging a trailer around, or dropped 15PSI in all tires, or lost 20-30 of its 118HP... Did not go a full OCI, swapped for M1 10W40 HM, and instantly power levels are back to normal, as well as MPGs. So I fully blame Valvoline MST 5W40 for that experience, but never tried it again.

That being said - I doubt your MPG is related to the oil. Unless the oil on the paper isn't what went in the crankcase. That's about the only scenario where I can see a vastly different oil grade playing a trick with variable timing sensors/actuators, and causing the MPG drop.

Also, check tire pressure. Maybe it was overinflated previously, and Valvoline Instant guys dropped the tire pressure to OE spec? Just guessing here.

 

[Ignatius]

Hard to figure this out....even if the VIOC used 5w30 by mistake I can't see it causing such a big drop in MPG.

It's funny because I was chatting with two of the guys that work at the shop about the fact that they have Valvoline Euro 0w-30 available and I asked them if they'd be willing to put that in the vehicle instead of the recommended 5w20. They said that they would not have an issue doing it because it's a fleet car but technically they're required to go by the recommendations. I would prefer that they use that or a full synthetic 5w30.

I think you have a couple tanks of gas as your sample size and it’s too small to mean anything, respectfully

FWIW I was given a different Bronco for a few days while my vehicle was in the shop for a recall and that one got even worse gas mileage than mine now does. It was about 6000 miles into an OCI using Valvoline Synthetic Maxlife 5w20. Other people at the company who drive Broncos report getting similar fuel economy as well so perhaps the question might be why my vehicle getting such good gas mileage as an outlier compared to all the others?

 

[pbm]

I'm interested in how many miles you can get out of a small 3 cylinder turbo in an SUV (or is it a CUV) going nearly 10K on an OCI? I specifically went for the 2.5 NA engine when we bought our Escape because I was leery of the small turbo's durability. Also, I really don't see a big gain in MPG over the 2.5 NA.

 

[Kira]

Re your better mileage: Maybe you're a thoughtful driver and your coworkers less so?
Also, turbo 'setup' can vary vehicle-to-vehicle.

Also, how much can you trust coworkers' mileage calculations?
As with restaurant recommendations, you never know what they're measuring.

 

[Graham Piccinini]

I'm interested in how many miles you can get out of a small 3 cylinder turbo in an SUV (or is it a CUV) going nearly 10K on an OCI? I specifically went for the 2.5 NA engine when we bought our Escape because I was leery of the small turbo's durability. Also, I really don't see a big gain in MPG over the 2.5 NA.

Hope the 1.5L 3-pot is better than last 1.0L 3-pot.
The 1.0L Ecoboost seemed to be a hit or miss. One member here went 230k on it before the timing belt broke, somewhat reliably and efficiently. While some other owners suffer from high fuel consumption, overheating issues (mostly due to cheap plastics for coolant system), or melting pistons, or just straight up lemons across the board.
The 2.5L was definitely the right choice. Reliable, efficient, good power, known to hit very high odometer milestones (with proper maintenance).

 

[partspro]

I had a large MPG drop once with Valvoline oils.
2003-2008 Toyota 1.8L (1ZZ-FE) VVT-i engine. Used syn-blend MaxLife 5W30/10W30/10W40 a handful of times with great results in that previously neglected vehicle. One day tried Valvoline MST 5W40 and fuel consumption numbers (hand calculated) went from 29MPG average to 24MPG average, and vehicle felt like it was tugging a trailer around, or dropped 15PSI in all tires, or lost 20-30 of its 118HP... Did not go a full OCI, swapped for M1 10W40 HM, and instantly power levels are back to normal, as well as MPGs. So I fully blame Valvoline MST 5W40 for that experience, but never tried it again.

That being said - I doubt your MPG is related to the oil. Unless the oil on the paper isn't what went in the crankcase. That's about the only scenario where I can see a vastly different oil grade playing a trick with variable timing sensors/actuators, and causing the MPG drop.

Also, check tire pressure. Maybe it was overinflated previously, and Valvoline Instant guys dropped the tire pressure to OE spec? Just guessing here.

Plus 1 and winter summer blend gas !! oops didn't see VVT , adds new level of complexity!!

 

[kschachn]

I want to know what the honorable.members of BITOG think about this one

Physics matters and it's in a little short supply here.

 

[Snagglefoot]

Were you driving to school? Because it’s uphill both ways.

 

[CharlieJ]

Ford's MPG specs for the 3 cylinder Bronco Sport are: 25 City/28 Highway/26 Combined.
You are achieving exactly what Ford has determined the vehicle should get.
Something else is amiss, and not likely the oil.

 

[Vercingetorix]

Ethanol?

 

[wpod]

So nope.

 

[Ignatius]

Re your better mileage: Maybe you're a thoughtful driver and your coworkers less so?
Also, turbo 'setup' can vary vehicle-to-vehicle.

Also, how much can you trust coworkers' mileage calculations?
As with restaurant recommendations, you never know what they're measuring.

There is an MPG meter on these vehicles and all are showing mid-20's fuel economy.

Hope the 1.5L 3-pot is better than last 1.0L 3-pot.
The 1.0L Ecoboost seemed to be a hit or miss. One member here went 230k on it before the timing belt broke, somewhat reliably and efficiently. While some other owners suffer from high fuel consumption, overheating issues (mostly due to cheap plastics for coolant system), or melting pistons, or just straight up lemons across the board.
The 2.5L was definitely the right choice. Reliable, efficient, good power, known to hit very high odometer milestones (with proper maintenance).

There is nothing special about this engine aside from the fact that it uses dual injection. Power is adequate at very best and fuel economy is disappointing even at 30+ MPG if you can get it. I personally see it as a potential ticking time bomb as far as long term durability.

Plus 1 and winter summer blend gas !! oops didn't see VVT , adds new level of complexity!!

Here in Milwaukee we're still getting freezing or near freezing temperatures at night, probably will not see summer blend until next month.

Ford's MPG specs for the 3 cylinder Bronco Sport are: 25 City/28 Highway/26 Combined.
You are achieving exactly what Ford has determined the vehicle should get.
Something else is amiss, and not likely the oil.

Doesn't explain why I way getting 30+ MPG for a few tanks.

Ethanol?

10%, may try 15% because it is substantially cheaper in certain areas I travel through.

 

[JoelB]

How sure are you it ever got over 30mpg? Seems unlikely due to it's weight and aerodynamics. Are you trusting the display screen for all these numbers or hand calculating?

 

[kschachn]

This post is about gasoline brand differences, an oil brand would be at least one order of magnitude worse. Tom NJ knows what he's talking about:

Best Brand of Gasoline

Get all my Premium at Sam's Club. Other places around here are 40-50 cents more expensive than Sam's Club premium, making it well worth driving a couple extra miles to fill it up. Get my 87 wherever it's convenient.

bobistheoilguy.com

 

[Lubener]

You got some other issue going on. No oil is going to make such a change in mileage.

 

[64bawagon]

One of the bosses at work complained that his Tahoe got worse mileage while he was driving it than the person previously assigned that vehicle. He even reviewed the fuel report and complained that other similar vehicles got better mileage. The truck was meticulously maintained and had zero trouble codes. I explained to him that it was his driving style and that he needs to take his left foot off of the brake pedal, he got mad and stormed away with all 3 brake lights blazing away the entire time he drove.