Big Drop in Mileage using 5w30 in '10 Cvic

[chubbs1]

My 2010 Civic has 10,870mi on it and from day one I felt it was rough and has a slight ticking sound. I tried PU, M1 EP, QSUD all in 5w20 weights. None seemed to quit the engine down..So, a couple of weeks ago I decide to put QSUD 5w30 in it. I was amazed at the noise reduction. Sometimes I thought the engine stalled because its feel was so different. I thought I hit the mark. Then I started to figure my gas mileage. I always get 28mpg/city,and my driving hasn't changed though I added 3oz. of Redline Rl-1 fuel system cleaner and the last two fillups mileage dropped to 25mpg. I have only to think the thicker oil caused this. Changed it out to EDGE 0w20 today. I felt bad for the waste of oil. Before I get bashed about all those oils I used in so few miles, I know its bad. This stuff is staying in the engine for a while. I will update fuel economy after a few weeks.

 

[Audi Junkie]

Winter fuel?

 

[sangyup81]

sounds like another case for the higher HT/HS = lower fuel economy theory

 

[HTSS_TR]

The drop in fuel mileage from xW20 to xW30 should be no more 2-3%. If it was 28 MPG with 5W20 and it is now 25 MPG with 5W30, it may happen during the change over from summer to winter fuel, also the weather get colder and your tire pressure drop several PSI, these changes may effect your fuel mileage by about 4-5% or more. I check the tire pressure to be sure that the cold pressure is no less than recommended on placard.

 

[4ever4d]

Sounds like you had to choose the lesser of two evils on this one,could the RL1 possibly have caused the drop in mpg,not likely but something to consider.My

 

[simple_gifts]

Too many uncontrolled variables to blame it conclusively on one thing.

 

[tinmanSC]

I doubt it was only the oil that caused this, but it may have played a part. I gotta echo the previous posts, I was probably winter fuel, tire pressure, who knows what else. I would find it exceptionally unlikely that that it was the oil alone.

 

[barlowc]

Originally Posted By: 4ever4d
could the RL1 possibly have caused the drop in mpg,not likely but something to consider.

Could be. I experienced a drop in fuel efficiency during a tank full last month where I used a bottle of Gumout Regane. The two-year average fuel efficiency on my Nissan is 30.8 mpg. The fuel-up just before the Regane came in at 31.5 mpg. The fuel-up with the Regane came in at 29.1 mpg.

But, I had another variable in play. The tank with the Regane was also run on fresh fill of PU 5W-30 whereas the tank before it was at the end of a 6K mile OCI of EDGE 5W-30 which was running somewhat thin per the UOA I had done.

 

[garlicbreadman]

my gas mileage went from 35 to 32 this tank due to weather dropping almost 30 degrees and driving in the rain. Oil alone will not make you lose 3 mpg.....sorry just doesnt happen, otherwise all engine manufacturers will require 0w-10/20

if you want a thin 5w-30....try Edge 5w-30, it is considered a 20 weight.

 

[chubbs1]

I thank everyone, but winter fuel in FL? The Temps for the last couple of weeks have been pretty constant too. That is a big mpg drop, I have been wondering myself what it could be. I know the oil alone couldn't have done that much in the way of fuel economy.

Is it the RL-1?? It says it will boost mileage 2-3%. I'm not so sure about their products anymore.

 

[Summerwind]

I have to agree with the others that oil weight within the ranges you used isn't the culprit...I've used up to a 10w30 weight oil in my Ford 4.6 modular which is specked for a 5w20 and noticed no lessening of mpgs. Quaker is a fine oil. I suspect that the RL "could" have something to do with it, also, are you filling-up with the same brands/kinds of gas as you were? I would doubt that you have winter fuel there in FLA, however I have noticed here a diff in mileage and performance among various brands. How is performance/driveability otherwise?

 

[chubbs1]

Originally Posted By: Summerwind
I have to agree with the others that oil weight within the ranges you used isn't the culprit...I've used up to a 10w30 weight oil in my Ford 4.6 modular which is specked for a 5w20 and noticed no lessening of mpgs. Quaker is a fine oil. I suspect that the RL "could" have something to do with it, also, are you filling-up with the same brands/kinds of gas as you were? I would doubt that you have winter fuel there in FLA, however I have noticed here a diff in mileage and performance among various brands. How is performance/driveability otherwise?


Used the same gas station and everything, it baffles me. I thought the car ran great on the 5w30, much better than the 20 wgt. I may have been a little too hasty in changing the oil out. Now I'm thinking it was partly the RL-1. there were no changes in temp or driving patterns. I have the same routine pretty much everyday. IDK

 

[demarpaint]

I doubt it was the oil that caused the drop in mpgs it could be a change in fuel. Does Florida use winter gas?

Edge 0w20 was a great choice IMO. It was the quietest of the oils I've used in my 08 Jeep which included PYB 5W20, PP 5W20, M1 0W20, and Amsoil ASM 0w20.

If the noise is still present and upsets you. I would consider a trip to the dealer since the car is still under warranty.

 

[flatlandtacoma]

Originally Posted By: HTSS_TR
The drop in fuel mileage from xW20 to xW30 should be no more 2-3%.


Should be more like 1% if he went from a 2.6-2.7 HTHS to 2.9-3.0. A 10% change in HTHS should result in about 1% change in MPG, all else being equal.

The accuracy of measuring gas mileage by a single fillup is probably no better than +/-10%. Many tankfuls (total miles driven / total gallons used) would be required to accurately detect a change of a percent or two.

On a long highway trip in my Civic Si (EPA rated at 30 mpg hwy) one fillup calculated out to 36 mpg!! Guess what, the next tank, same day, same conditions, same speed came in at 28 mpg. In reality I'm sure I got 32 mpg +/- on each tankful.

 

[uart]

Originally Posted By: flatlandtacoma
Originally Posted By: HTSS_TR
The drop in fuel mileage from xW20 to xW30 should be no more 2-3%.


Should be more like 1% if he went from a 2.6-2.7 HTHS to 2.9-3.0. A 10% change in HTHS should result in about 1% change in MPG, all else being equal.

The accuracy of measuring gas mileage by a single fillup is probably no better than +/-10%. Many tankfuls (total miles driven / total gallons used) would be required to accurately detect a change of a percent or two.
Agree 100%.

The underlying thing you were trying to measure is probably a few percent at best. It's difficult to get that accurate a measure of fuel consumption in just one tank so what you're measuring is mostly noise.

Here's a short list of some of the things that may effect your results.

- Slightly inconsistent fuel fill volume.
- Weather conditions, including temperature wind and rain.
- Traffic conditions.
- Route driven.
- Driver.
- Fuel quality and blend (summer winter ethanol etc).
- Oil fill level.

Don't forget this last one, an extra 1/4" (on the dipstick) overfill could cause just as much extra drag as the change in viscosity.

And just to prove how much noise there is out there I can honestly say that I've actually read the following two claims about fuel efficiency recently. In each case the person genuinely seemed to believe what they were saying.

1. Addition of 10% Ethanol (that is, E10) causes a 40% reduction in MPG.

2. Adding extra weight to the car increases MPG.

All of which goes to show that you do need to take stuff you read on the internet with a grain of salt.

 

[flatlandtacoma]

Originally Posted By: barlowc
The two-year average fuel efficiency on my Nissan is 30.8 mpg. The fuel-up just before the Regane came in at 31.5 mpg. The fuel-up with the Regane came in at 29.1 mpg.

Too many variables in measuring a small change in gas mileage from a single tank. The long term average in my Civic Si is 30.4 mpg. I routinely see individual tanks come in anywhere between 28 and 32 mpg for no reason other than that is when the pump clicked off when I filled it.

 

[CharBaby]

Check the tire PSI! IDK if FL uses winter fuel or if thy do, if they're using it yet. Your Honda may be that sensative. If the FL temp and humidity has dropped off, you MPG may have too!

 

[Texan4Life]

I would check tire pressure... and I always air mine up to the max psi it says on the sidewall.

Maybe try M1 Advanced Fuel Economy 0w-30?

 

[Hermann]

Originally Posted By: Audi Junkie
Winter fuel?


Do they have winter blend in Florida.

 

[Familyguy]

Originally Posted By: Audi Junkie
Winter fuel?


In Florida?