Oil weight?

[weekend warrior]

I have a 95 MX-3 with a 1.6L dual overhead cam.
What oil weight is recommended from the Mazda?
How many qts to fill?

Thank you

[Yoda]

I believe the correct weight of oil is 5W30 and you will need 4 litres

[rosso75]

3.5 quarts of 10w30

[RoundTop]

according to mazda 10w30.

warning: do not mix synthetic/non oils, or different weights. Only change when doing an oil change.

[dj inferno]

really... it depends on the temp... i belive that when it starts getting colder it says 5w30... and when its warmer 10W30

[manowar821]

DJ Inferno is right!

It depends on the weather. Colder weather calls for 5w30.

[Josh]

i run 10W40. i wouldent run anything else, 10w30 is too thin, and 5w30 i wouldent even consider that unless you lived in the mid west or something and it got down to tempratures like under 0deg. all threw the winter. thats the only time you would even need oil that thin.

[guyaverage]

5w30 and 10w30 oils are NOT too thin for this engine (or just about any modern engine any more). You want thin, try the 5w20 the Rx8 uses.

I dont know of any manufacturer that recommends 10w40 anymore. Dino 10w40 requires a lot of polymers to maintain a spread that wide and those polymers eventually burn and form deposits. And once they do burn, its not 10w40 anymore. I would stay away from it, unless you are doing very frequent oil changes. Its not like you are going to ruin your engine in short notice if you dont stop using it, but its definitely not the best choice.

If you are using a synthetic, then use just about any weight you want. Synthetic 10w30 is safe year round in just about any car. It wont shear and stays plenty thick to keep oil pressure high enough in a healthy engine.

[rosso75]

5w30 is recommended below 32 degrees. If you live in Alaska, use it in the winter. As for manufacturer recommendations of thin oils (5w30, or even 0w20 in some cases), this is all a bunch of crap. They recommend thin oils to help meet CAFE standards. You will not void your warranty by using thicker oils so long as they meet the API grade required.
Bryan

[guyaverage]

They recommend thin oils to help meet CAFE standards.

Absolutely right. Still, on the other hand, if they werent sufficiently thick for lubrication, they wouldnt recommend them either. They arent in the business of rebuilding and replacing engines under warranty that spun bearings for lack of lubrication. Oil doesnt need to be as thick as many think it does, especially synthetics.

As far as voiding warranty, be carefull with that. My friend had a Saturn that he was trying to do a lemon law return on (excessive oil consumption, been back to the dealer several times, they rebuilt the head, etc), and Saturn was refusing to allow it because he had receipts showing he had used 10w30 oil instead of 5w30, which was what the manual said to use. Its wasnt until after he got an attorney that they allowed it. So they WILL give grief over it if they think it will help their side, even if it is BS. My neighbor was the service mgr at the local Mazda dealer in the early '90's and he told me basically the same thing.

I have another friend who uses nothing but regular non-synthetic dino 15w50 year round, regardless of temperature, in his 2.8 v-6 S-10. He has over 300,000 miles on it now and its still going strong. Go figure..

[LongJohn]

Oil has multiple issues to deal with. It doesn't just coat the main bearings. Next time you are inside your 1.6L SOHC, take a close look at those tiny pin holes in the HLAs that it has to pass through, and you will start to worry about using oil that is too thick. Even the DOHC HLAs need thin oil.

Even when you talk about main bearings, then check the tolerance on a freshly rebuilt engine. There are not that many 0.001" clearance in the main bearings and the oil has to squeeze its way in there.

I laugh when I see that Lucas gearbox on the counter at the parts store. My oil doesn't have to climb up a stack of gears, it has to flow through small passageways and pump up tiny HLA mechanisms.

Big American V8's are built to looser tolerances, and the thicker oils are ok. Each design is different, and the designers know what they are talking about with their recommendations.

Working on the HLAs in my SOHC, and rebuilding a BP have given me a new perspective on the requirements of oil. I'm going 5W-30 synthetic as soon as the BP is broken in. I used to think you wanted to run the thickest oil you could get away with. Now I know better.

[Josh]

10w40 by no means is too thick, 20w50 definatly. 10w40 is probably the thichest you want to run in an import like our cars. the main reason i run it is to keep lifter chatter down. its not any different of a blend than 10w30, all conventional oils are going to break down burn and have deposits, its what they do. thats the whole reason to change your oil every 3K miles. and synthetics seem to be alot thinner in comparrison to conventional oils in the same weight. but thats the whole point w/ synthetic, lubrication.
also on a motor with over 100K miles on it, it would probably be a good idea to run 10w40 just for the fact its thicker. cause as the engine wears, oil clearences get a little bigger than when they were new. what do you think the whole point of the high milege oils are for.

[mitmaks]

5w-30, 10W-30, fine for mx-3. 10W-40 I use on my high compression 440 big block

[guyaverage]

its not any different of a blend than 10w30, all conventional oils are going to break down burn and have deposits, its what they do. thats the whole reason to change your oil every 3K miles.

Actually it is, in dino oils the higher the spread the more polymers are needed to give the base oil its multi-viscosity properties. They break down and form more deposits than a lower spread number would for that very reason.

10w40 and 20w50 have the same 30-point spread, but since the 20w50 starts with a higher-viscosity base oil it needs less polymers added to give it its properties and would be a better bet than 10w40 (in warmer weather).

and synthetics seem to be alot thinner in comparrison to conventional oils in the same weight. but thats the whole point w/ synthetic, lubrication.

Synthetics will lubricate better because they dont shear on the molecular level nearly as much as regular dino oils, they are more stable, and the ingredients that form sludge just arent there, so the engine stays 'cleaner'. A synthetic will lubricate at a much higher temperature and at a much thinner viscosity better than a thicker dino oil will in the same situation.

also on a motor with over 100K miles on it, it would probably be a good idea to run 10w40 just for the fact its thicker. cause as the engine wears, oil clearences get a little bigger than when they were new.

High mileage oils contain special conditioners to keep seals from drying out, some have 'friction modifiers' (probably zinc...I'm guessing, it may be something else) added, more detergents, and more additives to keep it at its intended viscosity. 10w30 "high mileage" oil isnt any thicker than regular 10w30 oil. It doesnt thin out as fast, but its not thicker to being with.

what do you think the whole point of the high milege oils are for.

Quite frankly, to make the oil companies more money. The world got by the last 80 years without it just fine. If you start out with the proper viscosity oil to begin with and change it at the proper intervals you really dont need it.

<small>[ November 11, 2004, 12:52 PM: Message edited by: guyaverage ]</small>

[rosso75]

As far as voiding warranty, be carefull with that. My friend had a Saturn that he was trying to do a lemon law return on...and Saturn was refusing to allow it because he had...used 10w30 oil instead of 5w30, which was what the manual said to use. Its wasnt until after he got an attorney that they allowed it. So they WILL give grief over it...

Yes, thats true. In most cases though they are wrong and they know it. Your friend got a lawyer, and they gave in. GM has a history of that kind of thing. Back in the '80's, when computers were becoming the big new thing on cars, Cadillac had their system set up such that the dealer could read the computer when the vehicle came in for repairs. The computer was programed to log any time that the car went over 65 mph during the first 1000 miles, and the dealers/GM were using that info to void the warranty. Their excuse was "Hey, the manual says don't go over 65 mph until the engine is broken in." They got sued. They lost.
On a slightly different topic, someone mentioned above that you shouldn't mix conventional oil with synthetic. Thats a common myth, and even the oil companies will tell you so on their web sites. From the Quaker State web site: "As long as the synthetic motor oil product and conventional motor oil product meet the viscosity and performance requirements outlined in the vehicle’s owner’s manual, you may interchange them with each other."

Bryan