kreativ

Lexus manual says to use either 5W-30 (preferred) or 10W-30 motor oil.

I've read it's better to use the smallest spread possible, which means in southern California weather conditions, 10W-30 would work fine all year round.

Is there any reason that the Lexus manual says 5W-30 is "preferred"? Is it just because it provides all-weather protection wherever you are in the US, or is the fuel economy that much better with 5W-30?

Here's an article about motor oil:
http://www.vtr.org/maintain/oil-overview.html

RON430

First number relates to the viscocity of the oil cold. The lower the number, the easier flowing it is when it is cold. Most of the manufacturers have tightened up tolerances to use a low viscocity when cold to get faster warm up and eak a few more percent mileage when cold. A multiweight tries to maintain a certain viscocity over a wide temperature range, the second number indicates the viscocity at higher temperature. In the early days there were probably some legitimate concerns about the additive package to generate a multiweight but I would think that a good quality oil today, particularly the synthetics, have no real problems in this area. There are a couple of guys that work in the oil industry here (Hey Mean Gene, you still here?) and they will probably post their feelings if you get their attention.

Gs400TRD

with a synthetic either is fine. I am running 0w-30 MB one in my car! and I live in TEXAS!!! Most Synthetics doesn't use thickers found in dino oil (castrol does dont use castrol). I haven't had any problems most synthetics have flash points in excess of 400F most engines run between 200-275F under extreme conditions...

So I say fo with a 5w 30 it gets to moving parts faster....Even faster 0w-30

kreativ

I've noticed that the price between the different brands of conventional motor oil can be pretty extreme. Castrol and Valvoline are usually the most expensive while Chevron and Exxon can be had for sometimes half the price. Chevron and Exxon are good gasoline brands, so is there anything to justify the higher price of certain motor oil brands?

RON430

kreativ - I think you could start a great war with that last question among the informed and uninformed. My guess would be that as long as you stay with a good quality name brand and change it regularly, it won't make much difference. Save the money. If you are not a believer in synthetics, I am but I am probably pretty **** in this area, I believe the hydrocarbons are also very good, in some ways superior which is why I like to break in with non synthetic and then switch over. Biggest reason I like synthetics is the extra margin of viscocity control versus temperature versus breakdown of regular hydrocarbon oil. But, I am a firm believer that regardless of the oil the biggest disfavor you can do your engine is convince yourself that oil changes are a waste of money. The oil has a lot of jobs to do and suspends a lot of contaminants from metal particles to dissolved gasoline and you just need to get it out of their on a regular basis or suffer higher wear and deposits. If it's a choice between a pricier name brand and a cheaper one (but still a quality, non reclaimed product) with more frequent changes, I vote for saving the bucks but not skimping on the changes. Now let's not get started and agree that changing oil without changing the filter is also a false economy...

aerodyne

I agree with ron...

I've run mobil 1 for 15 years, I'm a great believer in synthetics.

In answer to the original question, I have found I will get between 5 to 15 miles more per tank using 5w-30 Mobil 1 vs 10w-30.

Mean Gene

Ron - Now ya KNOW ya'll can't get rid of me that easily!! Gotta second the notion of 5W-30 over the 10W-30, even if U live down South like us. The 5W will get flowing quicker in the morning's first start ( where SAE tests have proved that 80-85% of the engine's wear occurs ) & since both of the multi-viscosity oils protect as a straight 30 weight when up to normal operating temps, the cold start lubrication is the deciding factor. Heck, both Reeves Callaway & John Lingenfelter specify M1 5W-30 in their turbocharged & supercharged engines. If U go with a conventional oil, remember that it's all basically the same crude oil when it comes from the ground ( that's my job ). It's the refining process that removes the impurities & undesirable characteristics ( like high paraffin content ). Since a synthetics basically man-made, it's easier to control it's quality. I'd stick with a name brand ( oil & gasoline but that's another thread we had about 3 months ago, wasn't it? ) because they/we monitor our quality control more closely than generics.
Hey mG - Didn't U work for Shell at one time? I just took a field engineering position with them so I'll be in Houston Friday to clean out my desk at Amerada Hess. Trying to see who I can hook up with while I'm there - been PM'ing Fever as well. Keep me in mind, my friend!!

Gs400TRD

Damn and you didn't put me down as a referral!!!
I work for Shell Oil Products...I am a down stream guy

I have mid terms coming up this week. and finals in a month. I decided to go back to school for an MBA...Hey maybe i'll be your boss j/k. But definately would like the meet the great Mean Gene!

let me know where in houston you will be located. I bounce around downtown and far west houston.

Gs400TRD

oopos forgot. Listen to the mean gene he knows.
basically oil is bought and sold from the open market, in most cases, the refineries do the magic and sell it. All dino oil are relatively the same just a few differeny detergents, additves, thickeners, etc. eventhough I heard that once you go havoline you have to stay havoline or you will have more oil burn.

kreativ

Thanks for the feedback everyone. 5W-30 it is. So the 5W-30s made these days aren't any more volatile than the 10W-30s? I forgot the reasoning behind using the smallest multi-weight spread possible.

I'd go synthetic, but in the future these cars are going to be off with the ladies of the household, and I doubt they'll be able to keep the synthetic streak going. If they paid for synthetic, the place would probably rip them off and put in recycled dino oil.
And I've heard it's not good to switch from synthetic back to dino oil, although I've also heard that's not a problem.

kreativ

Hey Mean Gene - Yah, we had that gasoline brand thread a few months ago...how all gas brands come from the same local refineries with each brand's additive packaged added in later, how the station brand doesn't necessarily indicate that's the gas brand you're getting, etc. In the end, I'm still going to Costco to fill up for convience's sake. I used to only go to Shell, until I discovered that at Costco's pumps it doesn't reek of chemicals like it does at the Shell pumps.

Do they even sell generic motor oil brands at your usual auto store (Kragen, Pep Boys) or places like Target? When I go there, everything looks name brand to me...Quaker State, Pennzoil, Castrol, Valvoline, Chevron, Mobil, Exxon, etc.

RON430

Hey Gene, I figured you were either spending all your time on some new sound system comp car or work. Houston. Sounds like we will finally meet racing our golf karts in Sun City. For the height of being ****, I like the first oil in the car to be non synthetic to make sure everybody has seated and a chance to build a tiny layer of varnish on rings. Then one load of semisynthetic, then full synthetic.

kreativ - I think it is far more important to have synthetic in my wife's car than mine. I love her dearly but when she walks in and says the car is making a noise, I expect to find three tires and glowing hulk in the garage. That extra temperature protection is for her benefit more than mine. After all, most of us are normally in the lead on the last lap of Indy as far as noticing strange noises in our cars. I have her go to a quickee change place but she buys the oil and filter at Auto Zone and just has them change the oil. Before anyone gets down on me, I don't mind changing her oil but she gets upset if I spend time on routine maintainence on her car so she gets oil changes and definitely gets the synthetic. I think she's special. Hope yours can be reasoned with. Not to continue preeching to the choir but those frequent oil changes and synthetic are definitely worth it. But for continued discussion, what about the 0W-30? Anyone interested or do we think it is advertising hype? Mobil is usually in the lead on this but to the best of my knowledge, no one has followed suit yet. That stuff must pour like water at room temperature.

Gs400TRD

I use it in mine...0w-30 from mobil is fine...actually 0w flows faster than water, Gene could verify this, water is the standard at 1. I have been using it for awhile and have not had any problems. I know amsoil make it also but they are special order and run about $7-8 a quart. Ow-30 is usually the same price as 5w-30.

quote from kreativ:
I've read it's better to use the smallest spread possible, which means in southern California weather conditions, 10W-30 would work fine all year round.

that is true with dino oil, because dino oils ose addtive to make the base oil get thicker (ie the 5w in 5w-30) the danger with a huge spread is under extreme conditions the additives can breakdown and you are left with the base 5w....bad!!! synthetics don't do this. ok

Mean Gene

K - Man, go back to Shell gasoline because it'll help my bonus next year!! Really need the cash flow now that our Brutus TLP platform is shut in until June ( defective valves & gonna cost us close to $400 MILLION in labor & lost revenue ).:eek: I've also adhered to the idea of not switching from syns to conventional oil because of the potential for sludge/varnish buildup but that would apply to running dino oil in the first place. As far as brand names go, I was thinking along the lines of stuff like the "Super Tech" brand of oil U can get from Wally World. Not saying it's a bad oil but just don't know enough about it to run it the GS but it's OK for the company car, IMO. Forgot about the 0W-30 oil but that's a little severe for my tastes - would consider it if I lived up North but since a cold day in Louisiana is right above freezing I'll stay with 5W-30.

Ron - I'm with ya on the gradual integration of syns except that I skip the semi-syn step entirely. Lingenfelter recommends conventional oil for the first 3-5k miles to ensure breaking in the rings properly ( syns can be too slick so it'll take longer but it WILL happen ). The 0W-30 is actually less viscous than water ( as mG said, water's the SAE & API standard of 1 @ 60 degrees F ). They use a special polymer to achieve this viscosity ( or lack of ) but we use a similar treatment offshore to push more heavy crude thru the pipelines & it's safe for an engine. I know the feeling about the "wife" thing. I love mine but since she knows nothing about cars & engines ( nor does she seem to care ) I take the extra precaution of using quality parts for the GS. Don't want here to get stranded plus she'll run the fire outta the car & then just shut it off w/o any cooldown time!!:eek: Maybe it's not necessary but this comes from my years of running turbos that I'll let the car idle for about a minute after a long trip/hard run before I shutdown. Shoot, the helicopters we fly have a 2 minute cooldown period so I figure it can't hurt!!

mG - I didn't use U as a reference because I was afraid Shell WOULDN'T hire me then!! Seriously, Hess is located over on Dallas Street so I'll be downtown myself. Gotta be a Hooters ( isn't that the standard CL meeting place? ) nearby so if ya'll see my black GS parked over there ( there's one off Westheimer, isn't there? ) Friday mid-afternoon, stop in!!

kreativ

Thanks for another round of good info.

Does dino oil go bad after a certain amount of time in the engine?

I noticed that Lexus' oil change interval is in the format of ____ miles or __ months. They say they're just calculating the months based on an average amount of miles driven each month, which sounds like just a way to simplify things for your average driver. They also say to change the oil "whichever comes first, the miles or months". Is that also another simplification for your average driver, or does oil really go bad after 6 months or so?