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I’ve used synthetic (Mainly Mobil-1) oil since the 1980s. Never saw a MPG increase (And I keep detailed logs). I mainly use it for the added protection. I like to keep my vehicles for a long time.
So I’m wondering if others have experienced the zero mpg increase with synthetic vs. conventional oils.
Also, what oils do you use? Castrol has Syntec and Edge. Is Edge worth the added cost?

I run Mobil One 10W30 in my Volvo 960. Since it only gets one oil change a year it makes sense to use synthetic. Toyota fills the Prius with their own 0W20 synthetic. From oil analyses I have seen this new Toyota 0W20 synthetic is a very high quality oil. Toyota recommends a 10K or one year oil change interval with this new oil.

Used to use Esso XD-3 0w-40 for my 2001 TDI. Full synthetic, relatively cheap, and a pretty high quality product. Was very happy with it. For my new car, Mobil 1 ESP 5w-30. One of the few oils available in North America that meets VW 507.00 spec. Have always used synthetic to keep the engine happy and run the recommended 10k mile oil change interval.

http://the-filtershop.eu/shop_ordered/4034/shop_pic/Mobil_ESP_Formula_5W-30_1_L.jpg

I use what Ford says to use which is approved 5W-20. Mobil 1 has an approved 5W-20 synthetic but I've never seen any better MPG than Motorcraft 5W-20 Blend using Mobil 1. I've never seen a drop in MPG throughout the 10,000 mile oil change requirement in the FEH and it doesn't improve after a change.

I have seen a ~1 1/2 MPG improvement using regular Pennzoil 5W-20 from using Motorcraft 5W-20 Blend, but the increase slowly drops at around 3,000 miles. I haven't tried Pennzoil in my FEH's because I go 10,000 miles between changes as recommended.

GaryG

I use Amsoil (for the price) and have never seen any difference in FE on any different oil. I suppose I just got tired of changing oil so now I'm up to 2 year intervals in all my vehicles. I do a fleet of 20 or so trucks/cars and we've done 1 year intervals for 30+ years. The first 10-15 years was mobil 1 and the last 10-15 years was amsoil.

I've used Mobil One since the mid 70's.

My Dad did not think it was worth it - Honda dealerships have discourage me, saying it gums up stuff.

Back in 92, I credit it for keeping a catastrophic oil pan rupture from ruining the 1988 CRX HF's engine.

I just change oil after about a year and 20,000 miles on my Insight. :)

Mobil 1 5W-20. At first for better MPG (no luck), then just to keep the car in top shape.

I tried 0W-20, but found that to be too thin for the Civic.

Now I run it because I'm sure it saved the engine from heat-seize after radiator problems at least twice during racing season last year.

3 changes in 3,000 miles, but its cheaper than an engine.

A good question is how often to change oil?

I generally do it every 3000-4000 miles....20,000 is the exception.

My leanings is sustainability of the engine is more important than more frequent oil changes that go into the recycle tank anyway.

Castrol Syntec 5w-30 for my wife's 03 Cooper S, this is a once a year oil change which is way under the 25,000 kms that they recommend.
Mobil 1 5w-20 for my 09 Vibe 2.4 which is usually twice a year due to mileage. And finally Kawasaki 10w-40 Syn in my 00 W650, again once a year change before I put it away for the winter, I have had no problems with the wet clutch on the bike due to using Syn oil.

Neddy.

I try to change my oil every 5,000 miles nowadays. That's up from the 3K I used to run. But I am a lazy sod sometimes, so I think it's been a bit more than 5K miles for this change.

-soD

I use Mobil 1 5w30 extended service in the Prius, but Mobil 1 10w30 in the 98 Suburban.

I initially used 5w30 in the Suburban, but the warmed up-idle-oil pressure was 20 psi(I think GM claims as low at 8 psi is OK), so I switched to 10w30(vehicle has 215,000 miles).
I can't measure any MPG difference between the 5w30 and the 10w30. Of course once warm the viscosity is about the same- so no surprise.
It does get 20-21 mpg on long hy trips-cc set to 68 mph but lots of road work, towns cities where speed limit drops-average speed probably 63 mph..
Charlie

Mobil 1 5w20. My Civic calls for 5w30, the van calls for 5w20. I like to only stock a single weight, and it (probably, but not measurably) saves a little gas.

10,000 mile oil changes, when both manuals call for 7500. I may reduce that to 5000 on the civic, since it's in "severe duty" most of the time. Cold starts, long warmup, high load driving when it is on, mostly short trips, dusty/sandy environment. The oil was quite black this last time.

We use Castrol ActEvo 10W40 in both bikes. It's semi synthetic though - does using fully synthetic help? (Help with with?, I could ask)
We keep factory oil change intervals, 5000km for Ciliegia and 10000km for Teresa (~3k and 6k miles, respectively). The smaller engine contains a bit less oil and revs more on the highway, but Ciliegia is steadily shifting towards a joy bike role - it's mostly Teresa who gets the hard work (bad weather, 2-up rides and motorways). She's on a break now, though...

I use Pennzoil Platinum...it was on sale for less than half of everyone else and gets great UOA numbers. I use synthetic oil because the winters here can go from +15 to -40C and cold start protection is important.

Pennzoil Platinum as well. It is available in town in 0-20. Change ones a year. 06 Prius and HCH2 get it.:D H

I wish I could use synthetic in the Echo, but it's got too many miles to start now. The Mustang could use synthetic if I used the right brand such as Redline which has sufficient ZDDP for my flat tapper lifters.

I have never noticed a measurable increase in MPG with synthetic in anything save for my other Mustang which picked up about 1mpg, and that I am certain is attributable to going with a thinner viscosity when I switched...

I started with synthetic in my Civic after it had conventional for 160,000 miles and 12 years. It still doesn't leak a drop of oil now at 182,000.

I don't know...203.000 miles + poor maintenance makes me pretty hesitant to start...

I don't know...203.000 miles + poor maintenance makes me pretty hesitant to start...

Go for it. Worst case, it starts dripping a bit, you replace the syn oil with mineral oil at the next change, and life goes on.

Usually that'll start a leak which won't stop...

I'm running M1 5-30w in my 06 HHR and follow the DIC readout for oil life. My last oil change was at 11000 miles and DIC got down to 10%.

I have an 88 Fiero GT with a crate 3.4L V6 that has run synthehtics M1 for the first 8 years since the engine swap and AMSOIL for the last couple of years. The car is used infrequently. The last oil change was after a year and a half and there was only 7000 miles on it.

I also have an 87 Fiero GT, bought new, that has been using dino oil every 3000-5000 miles or when I get around to it. It is another car that gets used infrequently.

All the cars get better MPG than EPA ratings.

My "97 Civic HX with about 215K miles doesn't leak oil - but it sure burns it. Most oils get "shredded" within a couple hundred miles, losing viscosity and then blowing through the engine. The car is spec'd for 5W-30.

This winter I'm running 5W-40 full synthetic Rotella, which is rated for diesel engines. It also meets the API specs for the Civic, aside from being W-40 instead of W-30. So far, so good.

Yeah, I use Rotella (albeit in 15w40 form) in both my Mustang and the Volvo I bought on Saturday...

I have been using Mobil 1 5w-30 on my Corolla for the past 4 years. First because I heard that it suits Toyotas well, then as I did UOA on outgoing oil I am running it longer and longer between drains. It's known to be good in my car for 12+ months and I have UOA to back it. :D Partly because I don't even add 6000km to the clock in a year.

The family Camry gets everything, Mobil 1/Quaker State/Valvoline/Pennzoil/Castrol/dino/synthetic/high mileage, I've used them all.

Both cars get an oversized oil filter - same base, only taller. Finally bought a box of 10 to be split between the two.

I started using Mobil 1 because of the Synthetic Oil Life Study (http://neptune.spacebears.com/cars/stories/oil-life.html). I've kept using it because it was readily available.

I'd been using Amsoil Maximum Performance 0w-20 in the Odyssey and Maximum Performance Signature Series 0W-30 in the Prius, with great UOA results at 10K. Blackstone suggested they could go longer but I never wanted to push it. Amsoil filters were easily taken to 20K. For comparison, my Honda dealer provided dino oil and filter were DONE at 5K according to UOA.
Recently switched to Mobil 1 in the Prius because it was so much easier to get, on sale for like $20 in a gallon jug and I wanted to do the change NOW. Also used their longer service filter (forget the name). No FE change of course. I'll probably stick with the Mobil 1 products now. Cheaper and easier to get on short notice.

- D

Honestly, I use whatever I can find on sale/rebate/clearance that is within grade... I lean toward synthetics in my Spectra, and conventional in my wife's oil-seeping Accord.

Right now, I have Quaker State Horsepower Full-Syn (now called "Ultimate Durability") 5W20.
I have used conventional 5W30 as well, and haven't noticed any difference in MPGs... but then again, the real differences probably come out in cold weather, and I'm guessing Florida wouldn't fit anyone's definition of "cold." :p

I'm guessing Florida wouldn't fit anyone's definition of "cold." :p

You can talk to me about the cold and I won't laugh. ;)

Here's some comparisons you guys may like. I don't understand them all. http://www.1syn.com/compare.html

I used Mobil 1 5w30 in Prius but 10w30 in the 215,000 mile Suburban.
I suspect it-the Suburban has some wear,and maybe the 10w30 is slightly better for it.
Of course the 5w30 will get where it needs to be more quickly, but maybe the 10w stays where it needs to be a bit longer- who knows.

I've used Mobil 1 for years. I mainly use it because I tend to be lazy, and occasionally run 7000-10,000 miles between changes(on the Prius which is a 12000 mile per year car-the Suburban is a 2000 city miles per year vehicle).

Do any of you (intentional, not forgetful/lazy like me) long change interval folks change your oil filter in between oil changes-say at 5000 miles on a 10,000 mile interval?

Thanks
Charlie

No. My cars spec 7500-mile oil changes, and the Ody wants a filter every OTHER time. I do M1 for 10,000 miles and a filter every time. It's only a couple bucks.

I have been running 10,000 on the Civic, but it was pretty black this last time. I'm thinking of doing a "severe duty" 5,000 change now. Short trips, cold engine most of the time, high-load P&G driving, sandy dirt driveway, old engine... thoughts?

That 1syn link above encourages me to continue using Mobil1. 2nd place on many of the tests and in the top half for all the others.

I have been running 10,000 on the Civic, but it was pretty black this last time. I'm thinking of doing a "severe duty" 5,000 change now. Short trips, cold engine most of the time, high-load P&G driving, sandy dirt driveway, old engine... thoughts?

For the Prius (in fact probably the 2010 Toyotas) the definition of severe duty is:
-mainly being used on dirt/dusty roads
-consistently used to tow trailers or with car-top carriers or heavy load use
-primarily used for short trips below 32 F / 0 C
-extensive idling and low speed driving like police/taxi/door-to-door delivery

I have been running 10,000 on the Civic, but it was pretty black this last time. I'm thinking of doing a "severe duty" 5,000 change now. Short trips, cold engine most of the time, high-load P&G driving, sandy dirt driveway, old engine... thoughts?


You can't judge if an oil is no longer protecting your engine based on it's color because the some of the additives change color due to temperature changes and suspended particulates - there are people who have a synthetic in their vehicles that have turned dark in 3,000 miles, but they tested the oil at 7500 and it was fine.

I can't tell you for sure if 10,000 miles is okay for Mobil 1 (although I think it would be); you'd have to get the oil tested (Blackstone, etc) and take a look inside the engine...take the valve cover off. Do you see varnish or sludge? Honda engines are very easy on oil.

Plus you have to consider, of those 10,000 miles, do you EOC? How many of those miles was the engine actually running?

Good point - I'd guess the engine was running for about 4,000 of those miles.

How much is an oil test? It's not much more to just change the oil anyway.

They average about $30. They're better for diagnosing engine problems (coolant leaking into oil, bad air filter causing excess wear, etc) than straight up testing the oil. They give you reports on the wear metals, amount of each type of additive, fuel dilution, viscosity (to see if the oil is now out of original grade) and volatility.

I've seen reports of Civics with 8-10,000 miles with Mobil 1 or other synthetics that have good reports. Granted, they probably aren't hypermiling, so the engine is more often than not up to temperature (to decrease fuel dilution).

I'd say a hypermiler's oil would more likely suffer from fuel dilution, due to more cold starts. How much is anyone's guess. It'd probably be more worthwhile to change it when you get antsy, but given your estimate, I'd say 10,000 mile changes are probably fine.

As I said in the other thread, this time of year my engine almost NEVER gets up to full temp. Only 170f this morning.

I'm still pondering this, but a 5000 interval roughly matches the 10,000 interval on the Ody, so I can do both at the same time, twice a year. Convenient that way.

If your coolant is only 170f, chances are your oil is colder still... changes that line up for both vehicles would make sense. :)

I would use SuperTech (WalMart) synthetic, since they're all the same*, but I need 0W20, so I have to get Mobil1. I change it every April, though I'd be willing to go up to 10000mi if I could in a year. I should probably have a UOA done to confirm that my interval is appropriate.

*there are differences in viscosity and base stock from brand to brand, but any API SL certified 0W20 is adequate to my needs.

I have only used 1 synthetic oil brand since i first read up and researched it, and that was Amsoil, they have the synthetic oil and a filter which is supposed to be good for 25K. My experience with it has been pretty good i have an older car so my engine could be eating up oil, but mine never gets to 25k it always seems to evaporate and get low but i manage 15k-17k on it, and the oil does not get very dirty its actually in very good shape.

I changed it once and i did alot of highway driving and the most Fuel economy i ever got out of my car was 250m on the half way mark. I always meassure by half way because i never let my car get on empty or anything so i think its the best way for me to measure it.

Now if i drive slow and good, i get about 220 but this is because my oxygen sensor is messed up now so i guess it makes the car run lean. Back then i would average 170-175 so 250 was huge lol.

Everytime my check engine light sometimes goes off, i get pissed because its such a huge hit to my mileage lol

Anyway thats my experience but from my research amsoil seems the best brand out there.

I use Amsoil 0-20w on my daily driver with the ea oil filter. Yes, it does well.

From this one mechanic i also heard that he can get 25k out of the amsoil with a fran or fram? filter, I use the signature series oil which is for older cars and that is good for 35k but the filter only goes to 25k max.

DON'T USE FRAM! Or at your own risk. I cut several filters apart like BITOG. The cheaper Fram was made out of stuff like a brown paper grocery sack.

im not recommending fram its just what i heard, i use the eo filters from amsoil too, im sure there isnt much a diffrence in price too.