MPG synthetic oil vs. dinosaur oil

slick1474 · May 22, 2012

I've read a lot of the oil threads here about what mileage is good or not to switch to synthetic.

My question is has anyone measured or noticed an improvement in MPG after switching from dinosaur to synthetic of the matching viscosity?

KayCeeJeep · May 22, 2012

Not gonna happen. Now if you make a dramatic change from a thick grade like a 10w40 to something like a 5w30 you could get a little boost in mpg.

If you're not running something overly thick for your Jeep, just switching to a syn from a dino isn't going to gain you mpg, at least not enough that you could even measure it. There are other potential benefits to a syn but you certainly won't get your extra money back in gas.

madmax · May 22, 2012

I think dino oil should be fine for our 4.0L engine because these engines (4.0L) was originally designed in 1964 (AMC 258, Typhoon Six). I wouldn't want to switch from dino to syntheic. Syntheic oil are much thinner (in molecule size) and can find a way to leak through the gaskets. Stick with dino oil and they're still good and cheap.

Syntheic oil should be used in modern engines as recommended by manufacturer.

Johnyre · Dec 3, 2013

slick1474 said:
I've read a lot of the oil threads here about what mileage is good or not to switch to synthetic.

My question is has anyone measured or noticed an improvement in MPG after switching from dinosaur to synthetic of the matching viscosity?

I got about 1-2 mpg on switching from 10w30 dino to 5w30 synthetic but I've only ran two tanks of fuel and its winter so we get crappier gas as well

04dubjay · Dec 3, 2013

Mothafluffin' dino.

dlundblad · Dec 3, 2013

After reading around on Bobistheoilguy.com, I've learned that the main true benefit to synthetic is longer oil change intervals.. Unless your Jeep has a turbo with oil cooled bearings of course. It'll get slightly more cost effective when you make your OCI around 10,000 miles though so that's about it. Heck you can push dino to 5000 miles.

The only way to achieve a noticeable mileage increase is to buy a Prius and install an Obama Biden sticker in the rear.

Ah673000 · Dec 3, 2013

Guys , use real research to answer this question. If you change your own oil then using synthetic makes total dollar sense.
Mobil has done extensive research on all kinds of vehicles for the past 40 years .... The data from the lab, streets of NYC and from Alaska and Arizona all confirms that the benefits of using synthetics are numerous and drive savings to the bottom line for the vehicle owner . My experience is an increase I mpg of around 2% on a 4.7 Jeep . But that is not the main reason I use it .... And so far my 160k mileage on my WJ confirms it for me.... 20 mpg on the road.... Burns little oil... And runs as strong as the day I bought it. Synthetic is cheap insurance if you have an overheating event.... It remains stable at much higher temperatures then dyno.

Nothing wrong with dyno oil.... But on the end you will spend more to get less performance.

Bandit84 · Dec 3, 2013

I haven't really seen any benefits other then easier starting in the winter. I do my own oil changes at every 3,000k and I figure the extra $10 bucks for synthetic isn't going to break my wallet..

LilyBayXJ · Dec 3, 2013

I switched from Pennzoil Conventional to Mobil 1 in a 4.0L V6 Tacoma I had, and recorded a 1 MPG gain.

I made the same switch in my LJ, saw no improvement, and it made the engine tick like a son of a whore. I'm back to using Pennzoil in it and all is well.

dlundblad · Dec 3, 2013

LilyBayXJ said:
I switched from Pennzoil Conventional to Mobil 1 in a 4.0L V6 Tacoma I had, and recorded a 1 MPG gain. I made the same switch in my LJ, saw no improvement, and it made the engine tick like a son of a whore. I'm back to using Pennzoil in it and all is well.

I ran M1 TDT in my Jeep for about 50x miles until it developed a tick as well. Switched to conventional pennzoil and it's quiet. The molybdenum does wonders.

MPG synthetic oil vs. dinosaur oil

slick1474

KayCeeJeep

madmax

Johnyre

04dubjay

dlundblad

Ah673000

Bandit84

LilyBayXJ

dlundblad

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