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

 

you double posted so here's what i said in the other thread:

 

Any oil will be fine, just change it often because the contaminants and moisture will not get removed from the oil because it does not get up to full operating temp on a regular basis. Your choice of oil will likely not help the engine survive any longer but then again you will be lucky to get 50-75k out of your rebuilt Renesis anyway. Just remember, when you do an oil change you are only removing about half of the oil in the system so your new, fresh oil is getting mixed with old, contaminated oil.

The best thing to do is have your oil tested at blackstone labs to get an idea of how the oil is holding up.

I live very close to the office as well and I don't leave until oil temps are well over 120F and then I drive fairly hard to work to make sure it gets up to temp. Although that is not hard to do this time of year in south Texas. I realize you don't have an oil temp gauge but even when the factory coolant gauges shows a normal reading your oil temps are still very low. It takes a good ten minutes of idling to get the oil temps up to spec and at least five minutes of low speed driving to get them up to temps.

 

FWIW, my '04 has 58k miles on it, and has been driven daily to and from the office (and quite often at lunch as well) pretty much that entire time. So, 7 year-old car + daily driven with 58k miles adds up to very short commutes, like your wife.

This is in Oregon, so morning temps range from 30f to 70f, depending on the season.

I usually wait for the rpms to dip below 1500 before I take off in the morning. In the winter, once or twice a week I like to take a longer drive to get the oil nice & hot. Other than that, no special handling.

I've run everything from 5w20 to 15w40, synthetic & non synthetic.

I'm still on the original motor and, with mods, it consistently makes over 210 hp. So I don't think the short commute and/or lack of extensive warming will dramatically impact the life of the motor.

I do agree that frequent oil changes are in order, as you will get more contamination with short commutes. I change it in the fall, at the new year, and the start of spring at the very least, regardless of mileage. Usually at least once more in the summer, but then I autocross and want the oil in good condition when I compete.

Another item to consider is Seafoam/water cleaning. You will get carbon buildup with short commutes.

If I were you, I'd run 5/30 dino oil in the winter.

 

Seven blocks? Why doesn't she walk?

 

^^ X2

Seriously, I don't know how far is your "7 blocks" actually is, but I think I can manage to "walk" a miles or 2 back to work and forth. its not so bad.

no offense here but I think if ur wife have to drive for 7 blocks worth of distance. your wife is lazy as ... blah.

back to ur original question, if u want "TRUE" Synthetic, try to stay away from 95% of Castrol and 85% of Mobil1 products.

 

...or ride a bike?

 

That would be assuming she is physically able and the conditions permit.

That aside, I would never use a gasoline/diesel powered vehicle to go 7 blocks. I would either walk, bike, bus, etc. Maybe something electric? Short trips like this in cold weather can be detrimental for a gasoline car, especially one that tends to build up carbon anyway.

 

I know this isn't an answer to your question but it's still a possible solution to your problem: Get her a remote car started installed. Since it's not good to be rough on the engine without it REALLy being up to temperature, she can't even really drive the car in a spirited fashion on her way to work if she wants to. If you get her a remote car starter you can avoid the issue of getting a different viscosity oil and she can drive the car how it NEEDS to be driven (to get the carbon out). Just a thought.