Motor Oil

[92Lex]

After reading the extensive pinned post "Everything You Need To Know About Oil" I kind of scratched my head and had second thoughts. I read through my owners manual and the recommended weight is 5w-30..but theres a chart in there showing that if you operate your car in climates from 0 degrees to 100 degrees plus that 10w-30 is okay. I live in California, so I figured 10w-30 would be the oil of choice because it doesnt get anywhere close to 0 degrees anytime of the year here. The thing thats weird is my car is hard to start when cold, its not like i have to crank the !Removed! out of it to start but rather it kind of hesistates when I first start it up, regardless of how warm it is outside. After my car is warmed up I could shut it off and itll start up real real easy for the rest of the day...its just the initial warm up of the day that it has problems with. Does this have anything to do with me using 10w-30 instead of 5w-30? Shouldnt I run 10w-30 anyways because its an older car with higher mileage? I curious to what everyone else on this forum is running in their Lexus, and weather conditions that the vehicle is subjected to. Thanks.

[92Lex]

BTW, Im using Mobil1.

[GRAND_LS 4]

5-30 offers a considerably noticeably better at start up, even more obvious on colder days.

10-30 is good for hot climates like AZ, but in cali, 5-30 makes a better choice.

Some suggest 10-30 with higher mileage engines, so as you can see, there’s a bit left and right on this and this is where you have to make your own choice. But since you have problems during start up (which I had too on my old car till I switched to 5-30) then maybe you should switch to 5-30 and try it out.

[SRK]

I use Mobil 1 5W-30. Regardless of mileage, there is no need to switch viscosities. Much of the information on engine oils out there is seriously out of date. Twenty years ago if you told someone you were using 5W-30, they would call you crazy. Forty years ago if you told someone you were using a multi-grade, they would call you crazy. Fifty years ago if you told someone you were using a detergent oil, they would call you crazy. Today 5W-30 is the accepted viscosity for most car engines, except for Ford and Honda which now spec 5W-20. Put a 10W-30 in one of those engines, and you just blew the warranty.

Use a synthetic like Mobil, use 5W-30, and relax. You will have done all you can do.

[VBdenny]

Use the 5W-30 Almost all cars use it now. The only thing you will accomplish with 10W-30 is to devrease gas milage and increase engine wear at startup. Mobil 1 is awesome stuff and gives all the protection you need. Some new cars use 0(zero)W-30

[92Lex]

Thanks, Im going to switch to 5w-30 for my next oil change. I just thought that once your car has over 75k on it switching to 10w would be more benificial to your motor. With the 10w-30 currently in my car Im getting 350 miles a full tank with the a/c on all day...I guess it wouldnt hurt to get better gas mileage.

[Lexusfreak]

I use 5W30 Mobil 1 as well. I use what the owners manual suggests. Having said that, what is the milage on your LS? Some use the slightly thicker viscosity with a higher milage engine due to a number of reasons, one being the car burns a slight amount of oil due to it's age. Remember to use a top quality oil filter as well. I use either the Mobil 1 or K & N oil filter......stay away from Fram! B)

[Dr. Henry]

Actually 10W-30 is the better choice. Unless you happen to live in maine or montana or alaska, always keep in mind that the less aditives the oil has the better. 5W-30 has more aditives than 10W-30 so it can perform better in colder temperatures, you should look at the second number, the 30, meaning that both oils perform the same in hotter temperature, only 10W-30 does it with more of a pure oil base. Pure oil burns with time, additives dont, they gum up the engine with residue. If the temperature in the area you live goes below 10 degrees in winter (thats what the W stands for), then stick with 5W-30. The owners manual recommends 5W-30 because it is OK for any Lexus sold in the US, from Maine to Florida. But for hotter weather you will be better suited with 10W-30

[92Lex]

My car has 92,xxx miles on it.

I live in California and its been 100 degrees where I live. I have 10w-30 in there but I think its causing my car to kind of hesistate on the first start up of the day....but it starts up just fine the rest of the day. Are you sure 5w-30 has more additives if any?

[SRK]

Quick lesson on multi-grade designations. The first number refers to the oils viscosity at a test temperature of -18 F. and the second its viscosity at a temperture of 210 F. This means that both the 5W-30 and the 10W-30 have the same performance at 210 F. The 5W flows better at cold start, and reaches the lubrication points of the engine faster during start-up. It also produces less parasitic drag in the engine, and better fuel mileage DURING warm-up, but not thereafter. A cold 5 or 10 viscosity oil is still thicker than a hot 30 viscosity. Viscosity is always temperature dependant in non-newtownian fluids.

Although viscosity index improvers are used to produce a muti-grade, they do not produce deposits during the normal service life of the engine. Forty years ago when multi-grade oils were first introduced, a great deal of work was done to ensure that this additive did not produce deposits as it was depleted. Modern wide-range multi-grades have to meet the most stringent tests in this regard, and any oil certified with the SAE, API and ILSAC meets or exceeds them.

Synthetic oils have a naturally high viscosity index, and consequently have smaller additive packages than conventional oils for visosity index, pour point depressants, anti-wear, anti-foaming and anti-oxidizing properties.

Nonetheless modern conventional oils are outstanding in their performance. Myths abound about particular brands producing "waxes" and other deposits, but rest assured the API would not have certified them for warranty purposes if they did.

Anecdotal evidence is no evidence at all.

92Lex, the 10W oil will cause the idle air control valve to open a bit more during warm-up than a 5W, but that will not be noticeable to the driver. The cold hesitation is more likely injector spray pattern and intake valve deposit. A can of Techron fuel additive may cure it.

[Lexls]

I also use Mobil 1 5W-30, I am very happy with it :D

[Lexls]

I also use Mobil 1 5W-30, I am very happy with it :D