MPG dropped after switch to 5w20

[97flairside]

My mpg have dropped significantly in my f150 4.6 when i switched to motorcraft 5w20. I had been using 5w30 M1 for a while with no problems.

What could be causing my sudden drop off in mpg with the switch?

 

[Al]

I seriously doubt the oil is the problem. In theory milage should go up. This engine has performed well with 20W oil in it as seen in tha Oil Analysis section. Search as I recall. Naturally if there is a problem with say bearing wear or something..20 wt. might allow more metal to metal and hence lower gas milage. I would tend to look elsewhere however.

 

[2004 F150 4x4]

How many miles on your rig?

 

[Terry]

Procure a oil analysis and use it to diagnose the issue.

The 5w-20 is not the causal.


Terry

 

[1kickbuttranger]

quote:

---

Originally posted by 97flairside:
I had been using 5w30 M1 for a while with no problems.

---

If it wasn't broke, why fix it?

 

[Dr. T]

For one you switched from a full synth. to a semi-synth. and secondly, the thinner oil may actually be decreasing your compression due to blow-by resulting in decreased hp and fuel economy. Confirmed with increased oil consumption...

 

[97flairside]

I will check my oil level and see how it is. Someone else had mentioned i might be getting blow buy since its a thinner oil.

I switched cause my dumb *** was thinking it might help with mpg. But it hasn't. Since I've done the oil change it has dropped. I have not changed my driving habbits or anything else on the truck since then and im getting crappy mileage. Im going to go back to 10w30 m1 as soon as i can pick it up at wally world.

oh and i got 108k on my motor.

[ September 09, 2004, 01:28 AM: Message edited by: 97flairside ]

 

[sprintman]

Personally I would have done the std two-bottle Auto-Rx high mileage cleaning regime first to clean the ring pack and then trial the 5W20. you could still do that by the way.

 

[97flairside]

auto rx cleaning? what is that?

 

[sprintman]

A nice treat is awaiting you at www.auto-rx.com. Or do a search here on auto-Rx or check the Additives, fuel, oil, cleaners section here. A clean ring pack is a good idea with any oil let alone 5W20 IMO.

 

[Sin City]

I agree with sprintman. Give Auto-Rx a try. With cold weather on the way you may want to consider using an ILSAC GF-4 5W-30 motor oil instead of 10W-30.

Link about ILSAC GF-4 motor oil. web page

[ September 10, 2004, 09:24 AM: Message edited by: Sin City ]

 

[97flairside]

why 5w30 instead of 10w30? i had used it all winter and never had problems before? what are th advantages?

 

[97flairside]

how exactly does this auto-rx stuff work? and how would it help me with my problem?

 

[Sin City]

quote:

---

why 5w30 instead of 10w30?

---

Primarily better fuel economy (about a 1 or 2% improvement) since that seems to be important to you. Also in cold weather a 5W-30 motor oil will circulate more quickly through a cold engine than a 10W-30 motor oil will and the thinner oil should give you a slight reduction in engine wear after a cold start.

Many people on this message board have had very good results with Auto-Rx and I would also give that a try if you plan on keeping your truck for some time. Also it seems that many places now have ILSAC GF-4 motor oils available at least in the 5W-20 and 5W-30 viscosities. Prices at the Wal-Mart in my area for ILSAC GF-4 motor oils that are currently in stock are $1.17 per quart for Mobil Drive Clean, $1.42 per quart for Texaco Havoline, and $1.92 per quart for Castrol GTX.

[ September 11, 2004, 08:46 PM: Message edited by: Sin City ]

 

[Rob Taggs]

From some information I've heard 5w-20 oil was put into production for predetermined obsolesence. Automobile makers know that profits go down when a vehicle last too long in their mind. Mazda and Ford are the main thugs behind this type of thinking. Ford says to put 5w-20 in a V-10 high performance engine? Please, who do they think they are dealing with? 10w-30 at the very least to protect the internals of the engine. Not all the nations car makers have this fouled logic. Ford in the past used very loose tolerances in their engines but, now they finally caught up in common sense and have decided to follow suit with their competitors and went with tighter tolerances. Proven fact, take a look at how many old ford pick-up there on the road compared to chevy pick-up trucks. Far more chevys than fords folks. On another note, I work for the Kansas Department of Transportation at the present and in the past I worked for a midsized Kansas town street department. With both places we had chevys and fords as far as pickups go. I asked the mechanics at both shops what pickup ends up in the shops with repairs the most? All the mechanics told me FORDS are in the shop far more often than the chevys ever are. FORD=JUNK!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[moribundman]

quote:

---

What could be causing my sudden drop off in mpg with the switch?

---

Metal on metal contact. Just kidding -- I hope.

 

[Patman]

quote:

---

Originally posted by 97flairside:
how exactly does this auto-rx stuff work? and how would it help me with my problem?

---

Auto-rx uses natural esters to slowly (but thoroughly) clean your engine, and it will also help stop minor seal leaks too (as long as the seal isn't torn completely) By cleaning slowly, and liquifying the sludge, it prevents large chunks of sludge from clogging oil passages like a harsh solvent engine flush would.

I saw a drastic improvement in my engine wear when I tried it on my last vehicle.

 

[TallPaul]

quote:

---

Originally posted by moribundman:

quote:

---

What could be causing my sudden drop off in mpg with the switch?

---

Metal on metal contact. Just kidding -- I hope.

---

Hee Hee, I am a thick head. 10w40 for me!

But seriously, if his bearings have more than usual wear, I would think the thin 20 weight stuff very well could result in metal to metal contact.

It would be interesting to know what the oil pressure is running with the 20 weight vs a 30 weight in his truck.

 

[theoilzone]

When you switched lubricants you really didn't change from a 30 weight (5w-30 to 5w-20) to a 20 weight as the Motorcraft 5w-20 synthetic blend lubricant is actually very close (viscometrically speaking in terms of centistoke ratings) to a 30 weight.

It's viscosity will show in an oil analysis as a 30 weight within 2,500 miles usually.

Some labs analyses will bear this out under unused "virgin" samples checked as a baseline lube for fleet analyses.

It's main advantage over the previous lubricant is its' oxidation additive package which is roughly 200% stronger than the Mobil 1.

Ford's Mike Riley led the charge to specify this increase in oxidation protection. My last examination of the product showed it contained a blend of group II and group III basestock.......not the usual PAO basestock technology utilized in the Mobil 1 formulas.

Given the statements you made and excluding an oxygen sensor about to go bad I would say that the basestock technology is the main cause of your mileage decrease.

It is physically impossible to have less fluid friction when switching to a PAO basestock formulated product from group II and group III basestock technology.

The exact opposite is true as in your case.

Oil is Oil.................

Synthetic is Synthetic ....

 

[MolaKule]

quote:

---

Ford in the past used very loose tolerances in their engines but, now they finally caught up in common sense and have decided to follow suit with their competitors and went with tighter tolerances.

---

I think you meant "clearances."

Some Ford products have engine clearances about 25% tighter than in prior years.

A lot depends on ring tension and wear. At 104,000 miles, your rings may not be flexing due to carbon in the grooves, and the lighter oil is not sealing combustion gasses as well.

Try Lube ControL with the Mobil 1 or do an Auto-RX treatment, as many have suggested.