Yeah, tell me about it. If you work in an un-air-conditioned shop, I feel sorry for you.
The grand-kids and their mother just came for a visit from Pa... during the worst time of the year. +100* every stinkin' day. If it hadn't been for a our pool, they would have spent the entire 3 weeks in the house. Boy are we glad to have our house back again. I had had enough of the Disney channel and Hannah Montana to last me the rest of my life, not to mention, "MOM!! MOM!!!" every five minutes.
RP seems to get very good reviews and is easier to get than Ams-Oil. It may be a lil' cheaper too. They are really pushing hard to go National.
I'm just outside of Austin and it can get pretty cold here during the winter too. The good thing is that it usually doesn't last that long... not like the summer. I love going outside on Christmas day in shorts and a t-shirt though, and like to rub it in whenever I talk to the rest of my family in Pa.

 

Haha, I go up to Oklahoma most of the time for Christmas. Once the temp drops below 55 I won't leave the house. They all look at me like I'm crazy. But being raised in 100+ temps for most of the year, you forget how cold 50 degrees is, haha.

 

If you run Thicker, the pump will not flow correctly.

The oil has been selected by people who are specifically trained in university to a doctorate level.

I really hope you don't think that you are more qualified than the people who made the motor to decide what is best for it..

Synthetic of the same weight is perfect if not better.

 

And how many of these "people who are specifically trained in university to a doctorate level." Actually drive a Mazda 3 and know my driving habits? Just curious.

 

I'm sure Brian is referring to the people that designed the engine to specific tolerances and know what the oil weight should be for that particular design.
I agree. Best bet is go with what the designers and builders suggest. They know the engine inside and out better than any of us.

 

The Engineers that Designed, built and tested your engine selected the oil that would keep it running the best.

Car companies love money and hate warranty claims.. If there was a better oil, they would have put it in there for you...

 

Lucky people,
Here in IL this year the winter went through a week with nothing but at least -17F, now in the summer between 75-85.

This can't be good on a car can it?

 

Well, the -17 can't be too good on the battery. That's for sure.
My last winter in Pa (and ultimately the reason I decided I'd had enough) it was -10 for two weeks straight. Some said (+/-)-30 with wind chill. That did make it feel much worse than it actually was, I'm sure.
It was so cold, even with my heavy parka and gloves on, that I had to deice the car 5mins at a time, then go in for 15-20mins just to feel my fingers again. That was not a typical Pa winter where I'm from however.

75-80 sounds pretty good to me!! It was again 104* here today. It was already 80* when I got up @ 4AM.

 

I've run Castrol synthetic in all my vehicles especially in winter and from my experience, you can feel the engine run smoother and with less vibrations (in some older cars).
Also, type of oil brand does make a difference. Castrol cleans as it lubricates and as a result has a tendency to turn dark sooner, but when you look inside your oil fill cap and see no oil residue and the metal is clean, like original, you know the oil is doing it's job. I once knew a jet engine mechanic who owned a Mazda MPV and lived in a hot climate. He ran only 20-50 and never had a problem. He stated the viscosity was needed in such hot weather otherwise the oil was like water and offered little if any lubrication. Where I live, I run 10-30 in summer and 5-30 in winter (Castrol or Mobil synthetic) and still change the oil every 5000Kms.

 

1. I don't see the cause/effect or any correlation btw tighter tolerances and engine oil weight......and I don't believe any car engines are designed to run on only one oil weight.
2. I own a 2000 mazda mpv, with a Ford duratec V6 2.5L, in year 2000, they spec'ed 5w30, and in year 2001, they spec'ed 5w20, for the same engine. Did they reduce the tolerances from 2000 to 2001? don't think so. I also don't think the PhD engineers have anything to do with this either.
3. For mazda3's I4 engine, I'd use a good synthetic oil, 5w30 is my choice, or 0w30 all year round.
4. Regarding start up wear, you'll NOT run dry with 5w30. At the initial start-up moment, you rely on the oil film that's left there on your previous car run, this is where synthetic oil could help, and a heavier weight oil helps too. ( also at play is the additive package.....but higher detergent works against shear stability)
5. mazda3 manual states that if you can not find 5w20 use 5w30 (in Maxico), which means the engine is designed to run fine with 5w30. In addition, the same engine/car is spec'ed for 5w30 in Europe. I highly suspect that spec'ing 5w20 is for their fleet fuel efficiency (CAFE?) reasons in the US.
6. If you look at ACEA (european) oil specs, 5w20 oils are all A1, which has a HTHS (high heat high shear) of 2.6, while 5w30 has HTHS as 2.9 (minimum, requirement). I'd find a good A1/A5 ACEA rated oil as ACEA is more stringent that API rating.
7. based on the comparisons I went though, Castrol Edge 5w30 is my choice.
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