[williamssd]

I am the proud new owner of a 2007 Mazda 3s GT sedan (loaded w/ MTX) and live in Bullhead City, AZ. If you're familiar with this area of the US, we regularly get daytime temps during the summer exceeding 120 degrees (but it's a dry heat! :lol: ). Everyone here recommends thicker weight oil because of the temps (during this past winter, the coldest we got during the night was 30 degrees, which caused near hysteria).

My manual says that if 5w20 is not available, 5w30 can be used. I've used Mobil1 5w30 every 3,000 in my 00 Honda Civic EX for nearly five years and it was great -- still no burning of oil and I regularly exceeded the old EPA mileage numbers (this was while I was still in Wisconsin). I am now considering using Amsoil every 5,000 miles for severe duty because of the heat, but given that I'm a "hard" driver (not afraid to rev a little during the summer with the A/C on, but no dumping of clutches, etc.) I want a little extra protection for my new baby.

I have even had close friends recommend a 40 weight oil here, but I doubt I can find a 5w40 in synthetic nor a 10w40 and even if I could it would probably void my warranty somehow (with my luck, anyway).

Thanks for all of the help,
- Steve

 

[D Bone]

I live in the high desert of SoCal, and it gets almost as hot as Bull Head. I use 5w-20 year round and would not hesitate to do so in BH. Mazda recommends 5w-20 for all climate conditions, and the many good UOA's of 5w-20 in hot weather climates prove it's a quality oil.



Darryl

 

[HouRman]

5w30 also works fine in hot weather. I've used it and can't say it decreased my MPG.

5w40 is not that hard to find.

Shell Rotella 5w40 Full Synthetic is a good oil I used in my motorcycles. I bet it's thick for your car though and might make it feel sluggish so I'd stick to 5w30 if I wanted a thicker oil. Best part is its only $13 for a jug at walmart.

 

[williamssd]

Many thanks for the advice. I've got a while 'til it starts getting really hot here, so I'll continue with 5w20. I may even stick with Mobil1 since I've found a replacement for the Mobil1 oil filter I used on my Honda... the Purolator Pure One. Many people tell me that I'm really into "overkill" with my oil change montra, but my Civic has served me well at 153,000 miles (131,000 over the five years I've owned the car).

Thanks again,
- Steve

 

[mshu7]

Ditto the 5w20! As SiXX has said, our engines are very easy on oil so you should have no worries with 5w20. If you're in a pinch and can't find 5w20, 5w30 will suffice. However, I wouldn't suggest going to a 40-weight just because I think you'll see a drop in performance and MPG's.

Advance Auto is running a BOGOF (no rebates) right now on Pennzoil Platinum which puts it somewhere around $3.00/qt which is good (for no rebates). M1 is good too but has gotten expensive so some have gone to other oils. Either way, sounds like you're 3 will be running good for quite a while. Good luck w/it!

 

[raitchison]

Personally I would (and do) use 10w30 in the summer and 5w30 in the winter. I'm not saying that 5w20 is a bad oil, but I believe that 10w30 provides better protection.

Remember Mazda (or more specifically Ford) only recommends 5w20 for North America for fuel economy reasons (makes their CAFE numbers look better). If you look at an owners manual for a Mazda3 in other places you will see they specify a range of viscosities depending on climate.

As for your warranty, they recommend that the oil be 5w20 but the only requirement is that it is API SL rated, which pretty much all oil is nowadays. You could (but I wouldn't) run 20w50 oil in your car without risking your warranty as long as it was API SL rated.

 

[cali_axela]

Has anyone here used 0w30? I'm about to do my first synthetic change (after a lazy 20k mile break-in period of letting the dealer change my oil with whatever the hell they normally use). I'm 99% positive I'll be going with my trusty Mobil1 0w30 synthetic, unless anyone has a good reason why it's worse for this engine than what others are recommending. It seems to clearly have the best viscosity range for both reducing startup friction in cold winter starts, and putting up with high-RPM racing in summer heat.

I don't see why any smaller viscosity range, such as 5w20, could possibly ever be better for our engine than 5w30 or 0w30. All this talk of using different SYNTHETIC weights in cold vs. hot weather seems a bit silly. I can see why if you don't wanna upgrade to synthetic you need to switch, but when better viscosity vs. temp ranges are available for about the same price, then why don't more people use the 0wNN synthetic weights instead of the 5wNN variant?

And don't tell me your 3 is ALREADY losing oil when it's too thin... no one here has a 3 that's old enough for that

 

[mshu7]

SiXX ran German Castrol 0w30 a while back but only stayed with it for one interval because it's just too thick to be running in our engines. I'm pretty sure he said there was a drop in performance & gas mileage.

5w20 has proven itself so I personally don't see any reason to use anything else. If you doubt 5w20, run it for a single interval and then send a sample in for testing to see how it comes back. Obviously, if you're racing you're gonna want to go with a good synthetic.

If you want more expert opinions, check out BobIsTheOilGuy.com