First oil change with the new Mazda 0w20 GF-5 with moly - Improved MPG

BGChicago said:
Hi guys, I just changed the oil my self at 5k miles with the new Mazda Genuine GF-5 0w20 with Moly and I got improved gas millage. I am not sure if it is because it is first oil change (e.g. factory oil thicker?, different?) or its a result of the new oil (I believe that) but I immediately got improved gas mileage. Before I announce the numbers need to say that it is the Sport Manual (so you don't get shocked).

Before: 60 mph ~37-38 mpg, 65 mph ~ 34-35 mpg (50 miles highway, cruise control)
After: 65 mph ~40 mpg ( (50 miles highway, cruise control).
It is exact same route. First day after the oil change I though it might be a reversed wind, so I waited a few more days. Same results both direction (e.g. not downhill/uphill effect). This is in Chicagoland.

When I mixed it with some city driving (more like suburban driving) I currently have it on 37 mpg avg with ~40 mph avg speed. I should also say that I have about 100 pounds weight in the trunk at all times.
I am just blown away from this vehicle. I used it for business and thanks God I did not buy some heavy burner so called "truck".
I hope this tech is also reliable! Thank you Mazda!

P.S. Someone please confirm if you have similar results after the first oil change with different brand oil.

EDIT: For those unaware, this oil has perfect characteristics. Here is a detailed information about is. That is the reason to chose it. I had some hard time finding it with local dealerships for a price under $8 a quart. Currently, ROTO in Arlington Heights should have a case and should be able to sell to you for $8 (or less) if you get a dozen. You can also order onlie - the cheapest places I found is HandAaccesories (google it) ~$6.50 a piece + $20 shipping for a dozen and Arlington, VA Mazda (just a bit more, but if you live there you can pick it up and save the shipping cost).

UPDATE:
Almost a month later and I will have to disappoint you. I never managed to repeat those "crazy" numbers posted above: same route, similar conditions, same gas stations, same speeds. However, the week I got those ~40mpg numbers was very warm 70+ F. Since then, it has been always cold - under 45 F. My conclusion is that the car generally burns more fuel when its called outside. And while this will be no surprise for short city rides, I can not explain why it is happening on long highway trips (50-60 miles). And by that I mean a difference of 2-3 mpg on the current fuel gauge, and so the average (my car stays in a garage and I start and go - no warm up idle. In addition the highway entrance is 1.5 miles away). Could the heater ( I keep the interior pretty hot) be the reason?
Overall, it still has better fuel economy with the new oil, but difference is not as much as I though.
Click to expand...


I just purchased a case of it online from the US. Plus some filters. My dealers around here don't know what it is. My mileage dropped as soon as the cold weather hit. Still, better than what my 07 3 did this time of year. Engine are small and do not generate that much heat anyway. With heat and lights, bound to affect mileage. Best way is to block the front at the grill. This keeps wind chill off the rad. Engine has an easier time staying warm. Will warm up faster on short trips as well.
 
Third fill up AFTER oil change with Mazda MQ oil 35.7mpg over 360 miles (average speed 39mph). Last three tanks average is now 34mpg over 1055 miles. +1.5mpg from last three tank average and +3.8mpg over three tank average with factory fill! Now to see if these results last.....
 
mazdachris said:
I just purchased a case of it online from the US. Plus some filters. My dealers around here don't know what it is. My mileage dropped as soon as the cold weather hit. Still, better than what my 07 3 did this time of year. Engine are small and do not generate that much heat anyway. With heat and lights, bound to affect mileage. Best way is to block the front at the grill. This keeps wind chill off the rad. Engine has an easier time staying warm. Will warm up faster on short trips as well.
Click to expand...

In general I agree with you. However, that does not answer my question. Heat is a residue product. Engine speed is independent to heat produced one you are in gear. With that said, I want to ask again - why does an engine generally burns more fuel in cold weather if we eliminate idle time? Further more, doesn't cold air have more oxygen?
 
Cold air has more oxygen for sure. Hense, more fuel goes into cylinder to balance out. More zoom zoom as well. Even though my cx is in garage over night, car still requires way more warm up time in the morning than in the summer. When engine is cold or not at operating temp it runs in open loop. Not taking readings from o2 sensors. Oil is thicker than when warm. Heater is cooling engine by blowing cold air thru the heater core. Steals heat from engine. To answer your question, engine operates most efficient when it reaches its operating temp. Engineers have made a lot of changes to engines and emmisions to get engines up to operating temp quickly. One that stands out in my mind is when they started putting the exhaust manifold at the back of the engine instead at the front where cooling takes place. Allows for quicker warm up of cat converter and quicker use of ecm managed air fuel mix. Set your avg gauge to real time instance. Watch how much fuel you are using until blue light goes out. In short, cold air allows for more air in combustion chamber, ecm adds more fuel to get perfect mix, which equals a little more zoom.
 
BGChicago said:
In general I agree with you. However, that does not answer my question. Heat is a residue product. Engine speed is independent to heat produced one you are in gear. With that said, I want to ask again - why does an engine generally burns more fuel in cold weather if we eliminate idle time? Further more, doesn't cold air have more oxygen?
Click to expand...

Consider that EPA required winter fuel mix has less heat content so it takes more fuel and lower mileage...
 
BGChicago said:
Are you really located in Massachusetts? The Mobil one is significantly thicker specially when cold (I think its the thickest 0w20 on the market) so you should definitely see some improvement with the Mazda GF-5.

There is no guarantee that your original oil was the same GF-5. As far as I know, this oil was not available even in bulks till early summer. Even the manual recommends Castrol Oil which means Mazda did this deal with Idemitsu late. Otherwise, why wouldn't they recommend their branded product? So most likely, the first 3 months of production had different type of oil.
Click to expand...

Yes, live in Taxachusetts and my mileage has dropped since it got cold here. On my next oil change I will try and see if I can get some of that Mazda oil. Not sure how I will be able to show any real gains attributable to the oil though as there are so many factors that can change that. I guess we will see. I'm only getting about 32 MPG now.
 
V8toilet said:
Yes, live in Taxachusetts and my mileage has dropped since it got cold here. On my next oil change I will try and see if I can get some of that Mazda oil. Not sure how I will be able to show any real gains attributable to the oil though as there are so many factors that can change that. I guess we will see. I'm only getting about 32 MPG now.
Click to expand...

I know a few Honda CR-V owners who would be very happy if they got 32 mpg.
 
I like this Mazda Moly oil. Cold morning start up is a lot quieter. My first oil change I used castrol 0w20 with titanium. Mileage got was a little worse. But still, its winter with no snow. Wtf. With Molly. Seems a little better.
 
I'm only getting 27mpg. This would have been a surprise, but I learned from the in-dash display that my average speed is only about 30mph!!! FML
 
NinjaNoises said:
I'm only getting 27mpg. This would have been a surprise, but I learned from the in-dash display that my average speed is only about 30mph!!! FML
Click to expand...

I'm getting 26 mpg (calculated), in 80% city traffic, my average speed on dash is mid-20's, so the MPG is in-line with EPA estimates.
 
Is the oil mentioned here the Mazda 0w-20 specified in owners manual for US owners?
 
It must be. In my owners manual it says to use Castrol 0w20. I had to import the Mazda Molly from US dealer. My dealer knows nothing about it and they use Petro Canada.
 
CX-SV said:
Is the oil mentioned here the Mazda 0w-20 specified in owners manual for US owners?
Click to expand...

From what I've heard, the Mazda dealers bulk-source their 0W-20 in drums from Castrol. The 0W-20 with high moly made by Idemitsu only comes in bottles. If you take your car to the dealer and just ask for an oil change, I'd presume that they'd use the Castrol from a drum, though that may vary from dealer to dealer. Does anybody have service records from their dealer that indicates which oil they used (weight, full or semi synthetic blend, brand, etc)?
 
Last edited:
Meat - I will look at my receipt later from my oil change/service last summer. Good question.
 
ReManG said:
Third fill up AFTER oil change with Mazda MQ oil 35.7mpg over 360 miles (average speed 39mph). Last three tanks average is now 34mpg over 1055 miles. +1.5mpg from last three tank average and +3.8mpg over three tank average with factory fill! Now to see if these results last.....
Click to expand...

Well, I might have jumped the gun a little but I had Skagit Mazda in Burlington, WA change the oil with the special Moly oil recommended by Mazda (they said they had enough Moly in stock for my oil change). I'm only through one tank and driving routes/conditions have been very similar to those before changing to moly but my MPG appears to have actually dropped by a few tenths of a MPG. I track MPG very carefully and drive the same routes so I can notice small changes in MPG. I was expecting a boost (which is why I changed to the moly after only 5100 miles) so this is a real disappointment. The engine also seems to run slightly less smooth and not rev quite as fast with the moly oil which was a real surprise to me.

I will continue to track my MPG but I will be very surprised if they get better (based upon the results of the first tank).

I've used Moly oil (marketed by Honda) in my motorcycles with dry clutches and I could definitely tell I had improved power and range and the engine would rev noticeably more freely after the oil change but the oil became alarmingly thin and runny after only 1800 miles so I returned to pure synthetic (the Honda oil was a synthetic/natural oil blend). The thing that surprised me about the Mazda Moly oil is that it looks golden amber (like honey) on the dipstick. All other moly oil I've seen is black. Moly grease is black as well. So how does Mazda get rid of the black color in their moly oil? Anyone know?
 
Meat said:
From what I've heard, the Mazda dealers bulk-source their 0W-20 in drums from Castrol. The 0W-20 with high moly made by Idemitsu only comes in bottles. If you take your car to the dealer and just ask for an oil change, I'd presume that they'd use the Castrol from a drum, though that may vary from dealer to dealer. Does anybody have service records from their dealer that indicates which oil they used (weight, full or semi synthetic blend, brand, etc)?
Click to expand...

My dealer (Skagit Mazda) uses oil from a drum if not specified (per service writer at dealership) but will use moly in the bottle per request (at a higher cost of course). My receipt says they used 5 bottles of "GF-5 0W20 W/MO"
 
mazdachris said:
I like the Molly I purchased. At -15 c the engine starts smoother and quiter. IMO
Click to expand...

That's what I was expecting based upon other Moly oils I've used in other vehicles!

I didn't actually watch them put the oil in but I don't think my Mazda dealer would switch to a cheaper oil from a drum while indicating they used the more expensive moly oil on the service record. Can you confirm that the moly oil from Mazda looks light golden color (like honey) on the dipstick? I've never seen an oil with high moly content that wasn't dark in color.
 
mazdachris said:
It was golden when I poured it in. I will check dipstick this weekend. As I mentioned, its minus 15. Brrr.
Click to expand...

Brrrrr! That is cold.

I appreciate the feedback, I'm surprised it can contain so much moly and still be golden. But the thread you reference discusses two different forms of moly. I wonder if one form does not have the characteristic black color.
 
Please log in or register to reply here.

Similar threads

GTXT23
Yes a 2023 CX-5 Oil Change Thread
2 3 4
Replies
66
Views
8K
N7turbo
N7turbo
FerrariF1
    • Like
Oil change volume difference - horizontal vs inclined drain
Replies
4
Views
1K
madar
M
S
Oil filter after 1st oil change (2024 CX-5)
Replies
13
Views
940
Tchman2016
T

Latest posts

Back