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Discussion Starter · #1 ·
so after alot of reading here and elsewhere on the web i'm thinking that synthetic might be the way to go starting with my 3k oil change...i'm wondering if people here have truly seen improvements in their mpg and overall performance

also, can you go longer between changes on the synthetic, or is 3k still recommended? thanks!
 

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some folks will say longer, some won't. Generally you will be able to go the 5K as recommended without issue. i've gone 7500 on my last car, and i've known folks that go longer. My dad's Benz calls for like twice a yr if that. I think he told me once a yr. i'd never go that long, especially where he lives.

My Quest I do it 3750 as the manual states. I know its overkill but oh well. I have no problems with going 5K with the mazda.
 

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[quote author=larryb78 link=topic=139940.msg3016097#msg3016097 date=1237988796]
so after alot of reading here and elsewhere on the web i'm thinking that synthetic might be the way to go starting with my 3k oil change...i'm wondering if people here have truly seen improvements in their mpg and overall performance

also, can you go longer between changes on the synthetic, or is 3k still recommended? thanks!
[/quote]

I haven't noticed any increase in mileage using synthetics. Mainly because our cars came with 5w20 already in them, which is rumored to be a gas-saver weight of oil. Can't go much thinner than that. What I did notice using Pennzoil Platinum 5w-30 is a reduction in valvetrain noise and a smoother idle. I still am not positive if this is a result of using a slightly thicker oil or just a different brand.

I sure hope your not planning on doing 3k oil change intervals using synthetics. Thats a waste of money, oil, time you name it. Mazda recommends 5k severe intervals on dino so, you'd be safe going 7500 on synthetics. Just fyi, when I switched to PP 5w30 I did a oil analysis at 7500 and my oil was still good for awhile. So I did another analysis at 10k and my oil still had some life left in it but I decided to make that the cut off. So now I change my oil every 10k and it is saving me a ton of money and time compared to dino oil. Im still averaging over 30 mpg on a 80% hwy 20% city commute for work, and thats in a 2.3 automatic. I am getting kind of bored so I may try out some other brands of oil here pretty soon.
 

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Just my opinion, but I don't see any benefit to running synthetic in the normally aspirated Mazda 3. Should be able to go 5,000 miles on regular oil no problem. I had a 2002 Mazda protege that I sold with over 130,000 miles with 5,000 mile oil changes using regular oil. Never had one issue. Engine still ran like a top when I sold it.
 

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3k mile oil changes are a MYTH promoted by dealers, Jiffy Lube, etc, because they are a high profit service & they can try to sell you air filters, engine flushes & fuel system flushes (even more profit & dubious use). Nothing but a waste of money & oil. Most reasonably modern cars have a manufacturer recommended 5k-7.5k oil change interval.

Synthetics are generally more resistant to breakdown then Dino oils, but still accumulate contaminants. I doubt that you'll see any measurable improvement in MPG.

I'm at 194,268 miles.

Full writeup here: http://www.mazda3forums.com/index.php?topic=65601.msg1142208#msg1142208

Not much has happened since 100,000 miles. I need shocks, struts & springs. Front rotors have been warped for at least 100k miles so I need to replace those, the rears are getting thin. Still have the original front pads, the rears have been changed out at least 4-5 times. Original clutch. I average 28-29 mpg. I go 7-10k between oil changes, sometimes have to add about 1/2 quart between changes, probably due to inconsistent fillings by Jiffy Lube. Had to change out my AC condenser due to rock damage. Windshield is cracked. I have a new Pioneer NAV/Head unit to install. Otherwise it runs fine. AC still sucks. Interior is still cheap. Seats are hard & uncomfortable. Cloth is coming loose from the door panels.

Would I buy another? Probably, because it suits my needs.
 

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I had M1 on my altima and I frequently went 7500+ on it without problem. there were two times that I had a slight leak and the oil was almost empty. I credit M1 for keeping the car going without issue.
 

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Discussion Starter · #7 ·
thanks for the info guys - on my previous car (94 galant) i went 5k routinely on dino, so i guess the 3k thing was me being a paranoid noob mostly - right now im thinking based on what i've read here & elsewhere that i'll probably look to go 5k with synthetic to start & see how it is from there

the major thing that has me scratching my head right now is the gas mileage. at this point im getting around 25mpg (1700 miles on the car so far), but i notice it creeping up every time i fill...i don't know if this is the engine breaking in, me getting more comfortable with how she shifts or what, but i'd really like to get to that 30+ category that i read about all over these forums - hell if i can get into the high 20's i'll be happy, so i'm looking to see where i can make changes that'll improve this...any suggestions would be greatly appreciated
 

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im at ~12,000 miles and i switched to synthetic around 11,000. havent noticed a difference in mileage but the engine does seem to feel a little smoother (driving/idle). the difference seems to be pretty negligible.
 

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I've used synthetic oil in various engines over the past 20 years or so. The only real difference I've ever seen is in low temperature start-up, where the engine turns over noticeably easier and oil pressure comes up faster. I'm sure synthetics really do stand up better to high temperatures as well but the effects of this are harder to see without tearing the engine apart and measuring things.

For me the better low temperature performance and not having to walk to the grocery store at -30 is good enough reason to use synthetic oil.
 

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My take on it...

Dino is good for 5k in most cases. If you're going to go with syn, run 7.5k, and more with a UOA. I run conventional in the warmer months and syn in the winter. Only real advantage in our cars is the low temp performance. No other need for syn.
 
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