Valvoline Restore and Protect Improved MPG?

[Gullible]

My daughter bought a 2025 Jeep Compass from Carvana for my granddaughter. After driving it around for a few days, she had two complaints; it had a slow oil leak and only got 13 mpg. I loaded up my ramps and took them to check out the leak, which turned out to be a loose Service Champ filter (considering cutting it open). The vehicle has over 41k and we both surmised it was used as an Uber (or such) or a rental. Told her that I would change the oil and filter, not knowing what oil had been used or when it was changed. Picked up 5qts of Restore and Protect 5w30 (on the oil fill cap) and an oem Mopar filter. She called a week later asking me if the oil could improve mpg because it had doubled to 26.5 mpg. I told her it can improve gas mileage, but that amount is sorta remarkable.

It wasn't until today, that I was in the process of loading up used oil for deposit that I noticed that the empty Restore and Protect jug I poured her oil into read 5w20. Grab the wrong jug off the Walmart shelf. The older I get, the less likely I catch my mistakes until it's too late. So, two questions: could the change to w20 improve the mileage that much, or had the car sat for period and needed an adjustment period to get the system to reliably report mpg. AND...do I need to dump the 5w20 asap or wait until a 5k change. Peace.

 

[melk]

No telling how long that old oil was run. I’d definitely cut open that filter if you are willing, should be fun to see!

I’d run the 5w20 for a normal OCI of your choosing and then switch over to 5w30 next time.

 

[Passport1]

You made a serendipitous error. Note and praise the granddaughter's awareness and driving skills for future changes with her Compass.

Like you, my age occasionally makes finding True North on the compass a challenge.

 

[wlk]

If it was a Uber the increase makes sense as it is not that much stop and go. Plus, your daughter may be driving ut more gingerly than P.O.

 

[Japanese]

So, two questions: could the change to w20 improve the mileage that much, or had the car sat for period and needed an adjustment period to get the system to reliably report mpg.

No, 20 cannot make such a huge difference in MPG vs 30 grade oil. It mostly depends on the driving habits and city/highway ratio.

Most likely her bad 13 MPG was in the winter and that may mean that her thermostat is not working properly and the car run cooler for longer periods of time. And now when is summer the thermostat is not that crucial even if it's bad—stuck open.
So, check if her car reaches working temp. quickly enough which jn the summer is no more than 5 min. after the car is started and if thermostat works properly.

Actually, I switched from Mobil 1 0W-20 to VRP 5W-30 and my MPG got better but that us because I used the 0W-20 during the winter and poured in 5W-30 like a month ago.

AND...do I need to dump the 5w20 asap or wait until a 5k change. Peace.

Tell her to check her oil level every week or teo because the lower viscosity oil may burn a bit more than 5W-30. Also, if it needs to add up oil—use 5W-30. By the end of the OCI the 5W-20 oil may burn a little more than usual. So, I may consider 4K oil interval vs 5K.

 

[AZjeff]

After driving it around for a few days, she had two complaints; it had a slow oil leak and only got 13 mpg.

An oil leak is easy to see (on the driveway) but how would you know it got 13 mpg after a few days? The mpg calculator in the car might have been reset before the car spent time being loaded and unloaded to get to her or something. The EPA estimate for a 2025 Compass is 24 city/32 highway.