Sudden increase in MPG PP10w30 -----> PP5w30

[Gilitar]

I recently changed the oil in my 03 Dodge Neon and used Pennzoil Platinum 5w30 (new formula). The previous oil was Pennzoil Platinum 10w30 (old formula). Now normaly I'm not one to claim that a given oil is quieter or that I saw an increase in MPG. Well, this time I have documented a pretty substantial change. Usualy this car get 22-23 mpg all city (horrible I know), but now after the oil change I'm getting 25 mpg all city. I do realize that I am no longer running the A/C, but this change in MPG was sudden right after the last oil change. There has been no change in driving habits and no change in route or traffic.

All this has me thinking.... What if I went with a 5w20 next time? Do you guys think I could increase the mileage even more? Thoughts?

 

[racer12306]

It's possible, I debated using 5w20 in my 04 but I am now going the other way to a 5w40

 

[Titan]

You stated the obvious. You aren't running the A/C now! I drove 49,000 miles last year on one car, and run the same routes over and over. Variables include fuel quality, wind direction and speed, consistancy of the pump guages that estimate how much fuel I put into the tank, consistancy of filling the tank up to the same level every time, and speed. There are other variables, too. However, the point is this: you cannot tell on a tank or two of fuel what your true MPG is. I plot the mpg of EVERY tankfull. I use the SAME oil (Pennzoil Platinum 5w30), the same filters. My mpg varies from a low of 26-something to almost 37. Usually, it runs 31-32 mpg. The first 12,000 miles rarely got above 30 mpg, but, the car was new, AND it was winter. Winter fuel tends to give lower economy, plus the density of the air is greater so the Drag Coefficient is higher. After about 15,000 miles, I rarely got below 30 mpg, even though the A/C was running. As soon as it cooled off a little, and I used the A/C less, average mileage crept up a bit to around the 32 mark. However, there are still blips up or down.

You just can't remove enough variables to make certain what lead to the difference you observed. I certainly don't think it was the difference in viscosity between Pennzoil Platinum 10w30 and 5-30.

 

[bmwtechguy]

If you were to try 5W-20 instead of the 5w30 that is probably recommended, at least try it in the cold weather. I would probably look at other ways to improve economy.

 

[racer12306]

5w20 was the recommended grade for 2005 model year neons. However, there were no internal changes to support the change in oil weight recommendation. So if you want to use 5w20, don't worry about it harming the engine.

 

[Gilitar]

Originally Posted By: bmwtechguy
If you were to try 5W-20 instead of the 5w30 that is probably recommended, at least try it in the cold weather. I would probably look at other ways to improve economy.


It's my understanding that the 03 Neon has been back specd for 5w20. Someone correct me if I'm wrong.

 

[racer12306]

I don't think Dodge back spec'd 5w20 like Ford did. But check my post right above yours (we posted at the same time).

 

[Whimsey]

Originally Posted By: racer12306
It's possible, I debated using 5w20 in my 04 but I am now going the other way to a 5w40


My 1996 2.0L Zetec Ford Contour it's spec'd for 5w30. I experimented with Castrol 5W-50 Syntec, before my BITOG days. I did several OCI's with it. I can honestly say that my seat of the pants power suffered and my mpg also suffered. The mpg loss was documented. Plus starting a cold engine in the winter temps was a "bit" more noisey with the 5W-50 in my engine. I went back to Mobil 1 5w30 and my seat of the pants power and my mpg got better. "Thickerer is not always betterer".

Whimsey

 

[frank2009]

i'd have to agree with Titan. On my last MPG check, i was able to get almost 36 MPG on my 97 neon with mostly highway driving and no a/c. On the next check, and limiting variables the best i could, my MPG decreased to about 32 MPG with some a/c use. just my opinion but i don't think a 10% difference in MPG would be attributed to a small change in oil viscosity.

 

[Gilitar]

What about the formula change? Do you guys think it could have made a difference?

 

[Titan]

Originally Posted By: Gilitar
What about the formula change? Do you guys think it could have made a difference?


Not a measurable one, ESPECIALLY given all the other variables. Look, I'm not saying you didn't have an increase in mpg, you may have. I'm just saying it's not because of a few tenths of a centistoke of viscosity change... Hitting more of the traffic lights "just right" would be hundreds of times more powerful in achieving higher efficiency than the difference between a 20 weight and a 40 weight.

 

[racer12306]

Originally Posted By: Whimsey
Originally Posted By: racer12306
It's possible, I debated using 5w20 in my 04 but I am now going the other way to a 5w40


My 1996 2.0L Zetec Ford Contour it's spec'd for 5w30. I experimented with Castrol 5W-50 Syntec, before my BITOG days. I did several OCI's with it. I can honestly say that my seat of the pants power suffered and my mpg also suffered. The mpg loss was documented. Plus starting a cold engine in the winter temps was a "bit" more noisey with the 5W-50 in my engine. I went back to Mobil 1 5w30 and my seat of the pants power and my mpg got better. "Thickerer is not always betterer".

Whimsey


Thats a bit thicker than what I'm going with. I'll try it and we shall see.

 

[Curious Kid]

Since trying Valv. HM of like grade I've noted a 2mpg increase, but as there're so many variable that even go beyond knowing...I take it with a grin of salt and enjoy the extra out of the tank fill.

I try not keeping such a close monitor on mpg now, as I've found it just another nagging thing that would make me rather, well, NOT use the car. That's great when I can walk and so forth, but I'd find myself feathering the throttle, being concerned about extra weight, etc...all of which can unfoundedly make one change for the way the vehicle was designed. In some cases I've found mpg decreases and becoming nothing more than an irritation to others, or so I've thought at times and thus changed to focusing back on what's most important - driving safely and keeping things maintained overall. To some degree, the rest will follow.

A little further on a tank of gas...a little longer between fill-ups.

Take care.