duworm

I have a 2005 with 48K miles. Dealer just put in a new engine. HOLY CRAP, it is way better than the original engine.

I hate to say it, but was my wife’s birthday present so I don’t get to drive it as much as I would like.

I know it is a terrible way to treat a rotary, but my wife’s office is seven blocks from the house. The engine does not get warm before she makes it to the office. Winters here have low temperatures in the upper 20’s. Summer at her mom’s is as high as 104. Most of the time it is pretty mild.

So here is my question. What is the best oil weight for a car that has a LOT of short, very short trips on it? I am asking about viscosity not brand names

I did a lot of research on this web site. There is a lot of discussions for the “best” oil or oil for racing conditions, but I could not find any for my situation. Reading a LOT of posts here and places like Bob the oil guy, it seems like 0w is the best oil for those early morning starts and a lot of short trip starts. 30 or more seems like the best for the heat. So it seems that a 0w30 or 0w40 is the best answer to the question. So did I get this right? I am not worried about cost.

I am going to run synthetic, not a blend (so that seems to take Castrol and Mobile1 out of the mix). However, I get lost when it comes to the additives that vary from mfg. to mfg. The list is long and there seems to be some debate as to how much of each additive or base material is good. Are there particular additives that a rotary would benefit from? Are there certain oils or brands I should stay away from?

Please, I know many of you out there are in love with your particular brand of oil. I know what the owner’s manual recommends. I am most interested in why doesn’t every engine require 0w30 or 0w40. It seems like a no brainer. (I know the cost argument).

Am I headed in the right direction for an oil choice for short trips? Yeah, I know the best solution is to buy a different car……………………………………………

Thanks in advance.

Sherman

laythor

any oil will be fine. Don't get caught up in the best oil argument that has been raging here since the boards began.

If you're really scared you can switch viscosity for summer and winter.

Regular maintenance is the only proven thing to help the longevity of our engine. People have lost engines early regardless of what type of oil, premixing, sohn adapters, etc. Other people have had engines hit over 100k with nothing more then regular oil changes using the mazda recommended oil weight.

Just enjoy the car and follow regular maintenance, and enjoy the heck out of your wife's car.

usnidc

Also, getting the car out once or twice a week for a few WOT runs after it has been warmed all the way up will help keep the carbon away and burn off any condensation in the oil built up from the short trips.

40w8

You got the point of different weights.

It's whatever the operating temp hits.

I do mostly 80mph cruises to the track for 400 miles, then, put the hammer down for 100 miles, and I use 0w40.

So for someone that does'nt put the hammer down or warm the oil?

0w30; you answered your own question right!

The 0w's are the latest oils and I think are synthetic by default (even Mobil), so you can't find something bad in these weights.

5w20 is still too thin unless used below zero during the winter (front bearing wear).

monchie

Do you really need 2 threads about this? Here's the other one you've posted...

https://www.rx8club.com/series-i-tech-garage-22/short-trip-really-short-trip-engine-oil-218032/

slvrmzdrx8

I drive about a mile to work one way, so the car just gets warmed up when i get to or from work, red lights depending. So what i do is on like Wednesday night i will go for a little run around the block and get her hot and run a couple cycle up to 7-8 grand. Then i always go for a good drive on the weekends somewhere and give her a good run then too. I feel like its sufficient, not as good as giving her a good run everyday i drive her im assuming, but better than none at all i guess.