Hyundai Santa Fe Significant Drop in MPG

pgatz

I recently had my oil changed at a local place and not the dealership. Before the oilchange I was averaging around 20-21 mpg between city/hwy driving per tank.

I have filled the tank twice with gas since then and have averaged only about 17 mpg. It may not seem signifcant to some, but the second tank was a 230 mile round trip highway drive....

Any thoughts as to what the issue might be?

paulnz

pgatz,

You did not specify what year and trim level Santa Fe you have. I have a 2008 Limited and Hyundai specifies 5w-20 oil for it which is somewhat thinner than the "standard" 5w-30 oil. What weight oil did the oil change place put in yours? If it was 5w-30 or (worse) 10w-30, that could account for your drop in mileage.

Also, I noticed here in Ohio that when the temperature really dropped (went to around zero in the morning) that I lost 2-3 mpg just from the cold. My SF has the mpg indicator and I reset it every tank. In the warmer weather, I was getting 21-22, in this cold it dropped to around 19. Also, I have found that driving in wind makes a big difference in mpg as well. The 2007-2008 SFs are larger than the earlier models and seem to have more metal to catch the wind.

pgatz

I have a 2007 Santa Fe SE. the place put in Castrol 5W20 oil. I live in Illinois, and we've had some downright frigid temps the past couple of weeks. However, yesterday when I drove to central Illinois, temps were closer to 20 degrees ... I had the car last winter and never had issues with gas mileage like I am presently experiencing.

almatti

I experience the same drop in MPG during the colder weather months in my G35X Infiniti too. It's the Winter Blend of Gas that seems to affect the MPG in all cars.

jcwsbltd

Although you've not stated any previous mpg versus new mpg fiures,just "significant drop", there could be several reasons for the drop in mpg:

1. Such Low temps are causing the automatic choke to stay on longer or causing it to stick

2. The blend of winter gas is causing lower mpg

3. Someone re-set the trip computer mpg and it hasn't adjusted for mixed driving yet

4. Slower town speeds or more idling/warm up will significantly reduce mpg.

It all depends on what "significant drop" means - realistically in such cold weather you would be getting anywhere from 15-18 mpg in town driving - NOT what the trip computer says the mog is, as this is an average figure. I presume you are actually measuring the amount of gas you're putting in versus the actual trip mileage in between tanks?

Bad08Sonata

Are you setting your emergency/parking brake between drives?

Maybe your parking brakes are dragging or are not completing releasing.

cold weather might be freezing lines

pgatz

The car is garage parked, and I do not use the parking break for that very reason..

pgatz

I reset the the mpg trip computer with each tank of gas. I discount mixed driving from all highway driving tanks. However, when I know that the last tank was ALL highway driving and I got 16 mpg from that tank and the previous mixed driving was about the same, that's an issue.

I had the oild changed at a local place recently and I'm reading in other places on the forum about the uniqueness of the oil filter for the Santa Fe. I'm wondering if that place put the wrong filter in. Guess that means a trip to the dealer to find out.

notmybmw

I'm not a "licensed" mechanic.......but, I am "a" mechanic. I would find it hard to explain a 30% drop in gas mileage based on choice of oil filter. (Unless you heard some really weird noises....suggesting that the engine was operating on the edge of "seizure" on a constant basis. LOL)

Mike