Im going to switch to 10w 40 Next week im done with 5w20

 

does the brand of the oil really mean much??? i mean by the looks of things, im probably going to go with 10w-30...but does is matter what brand of oil i use???

 

i live is southern california, the weather is mostly warm lowest probably around 40-50 C in the winter and 90-100C in the summer... ive been using 5-20, what do u guys recommend? ive been going by the manual since day one...

 

I've been using 5w-30 Royal Purple in mine, WV here.

 

I would go 10W-40 in SoCal. (and you meant F not C, right

 

lol yeah... he he...my bad. F not C...

 

Here's the big question for me, if my motor fails and I have documented 10w-30 oil changes.. How good of a defense do I have when they say "the manual states 5w-20, 5w-30". I really believe 10w-30 or 10w-40 is best, but at 60k is it worth the serious risk having them void out the warrenty and having a solid argument... Just curious about opinions on that


Ha, and bump to a 1+ year old oil thread

 

i live in southeast Texas (Houston), had my car since summer 05', been using Castrol gtx 5w-20, car runs fine. The summers are HOT and the winters aren't that cold, very few nights at or below freezing, although this last one had snow, which is an oddity around here.

Shall I stick with 5w-20?

 

In Dallas texas and its too hot to run 5w-20 IMO. Ran 5w-30 gtx on my last engine and on this new one ive switched to 10w-30.

 

I'll probably bump up... It's that idea that if my engine blows and all my receipts say 10w-30 there's a good chance I'm out of luck.. That's what's killin me about making the switch.

 

I have the same problem. I'd like to switch, but I can't imagine a dealer would overlook that.

 

Buy your oil at Walmart. Their receipts dont specify oil weight, just oil brand. So make sure you dont buy something obviosly synthetic like royal purple. I buy castrol gtx in 10w30

 

good idea.

 

at least 10w40.

 

not doubting your guys oil theory, but is thicker really better?
I still dont get why summer requires thicker oil since engine temperature is regulated by the cooling system.
and also thicker oil means lower flow, so would it be slower to take all the heat out of the engine than thinner oil?

 

well, the engine will be sucking in hotter air... how much difference it makes to engine temp, I don't know.

I think some of it might have to do with start up. Think of syrup in the microwave. If the oil is too thick when it's cold, it puts more wear on the engine until it's warmed up and flowing well.

However if it's too thin and the engine gets hot (running it hard or whatever), the oil will start to break down and not protect as well...or something like that.

I think that's how it works.

Having two rotary cars, I should know this kind of stuff more than I do.

 

I think oil is magic.
gets hot, I think the oil inside the rotary doesnt really get that hot comparing to a piston engine cuz its only to lubricate the gears and shaft.
too thick oil creates more ash thus more carbon build up
and I dont think it would get that hot since oil coolers would regulate the temperature too

 

that makes more sense than how I tried to explain it.

...maybe it's a government conspiracy meant to confuse us all

maybe. that's beyond my level of knowledge.

 

Because there are so few moving parts in a rotary engine, oil is just as important as water/coolant to remove the heat from the engine. And, there is more heat produced in a rotary engine than a conventional piston one.

 

then I think higher velocity is better in this case.

 

maybe thicker oil absorbs more heat?

 

oil has very simular heat absorption values, so...

 

This prompted me to look at my Pep Boys receipt from my last oil change. It only shows "Castrol GTX" (no weight), so I'm happy !

 

The motor oil plays a big part in internal engine cooling, as it is used to cool the rotors (which get very hot). Why do you think Mazda included 2 large oil coolers?

 

IF it comes down to it, use the chart you see in my link, it comes from japanese Mazda RX-8 manual and is as close to base as you can get with this car.


To answer some questions. the only time we need to really worry about the first number is if the weather routinely goes below freezing, if so, may want to run lighter W weight so the engine IS properly lubricated at start up. if 0W-40/5W-40 exist, i would recommend it for cars in the northern areas. for warm climates, 10W-30, 10W-40 is what i recommend.