what's the difference between 10w40 & 5w30 oil & which is better to use in very cold weather?

Answer 1

in the olden days of muscle cars, they only had single viscosity oil.
Like 30 weight, 50 weight, etc.
This type oil was not multi-viscosity like todays' 5w-30, 15w-40

Multi-viscosity oil like 5w-30 is like 5 weight oil when it's cold, and 30 weight when it's hot. Which basicaly make your car start easier because the oil is thinner when cold.

If you look at the back of the oil bottle it will give you a guide for the temperature range you live in.

Realy cold weather 5w-30
Realy, realy cold..0w-30
California weather 10w-30

Answer 2

10w40 is harldy ever used anymore (do not use it unless you have a car that calls for it, mostly older cars). 5w30 is VERY thin, so it heats up & breaks down very fast. You forgot the other option which is 10w30 & this is the oil you should use all year round (unless you are in the artic). People will tell you 5W30 is better (which it is given the choice of that or 10w40) but 10w30 is the best for normal cold winters (like New York or Chicago type). I have driven in some of the coldest of winters (-60 with the wind chills) & have never had a problem with 10w30 oil.

You may also hear that you should let your car warm up for 10 mins before you drive it. This is another myth as you want to put the engine under load (in drive & in motion) as soon as you can. While the engine is "warming up" for the 10 mins (in idle) the rpms are much faster & not much oil is getting to the required parts. There may be times it is sooooo cold that all your fluids are goop, so you have to give it a few mins to warm up. But as soon as it will let you, put the car in motion.

Answer 3

OK, off into the deep end...

The first number denotes how the oil flows at a cold temperature. Lower the number, the easier it flows when cold. Second number (after the W) denotes how the oil flows when hot (operating temperature). Larger the number, the better for some cases.

Most new cars are designed to run 5W30 year-round in most climates. The proper weight for your car depends on year of car, mileage on car, and how cold or hot it's gonna be outside when you start it.

Answer 4

To be simple and brief, you need to understand that there are two kinds of lubricants
1. Monograde
2. Multigrade

A monograde lubricant does not have the ability to maintain its viscosity in hot and cool weather.

Over the period of time the lubricant users felt the need to have a lubricant which could maintain its viscosity in hot and cold weather - (not to be too thin in summer and not to be too thicker in winter or very cold weather). Because people had to travel to a variety of places hot/cold/mild without having oil change, the engineers developed a multigrade oil.


To answer the second part of the question, which oil is better, your OEM recommends the oil viscosity and it is mentioned in the catalog. Use that oil only.

Note: (Original Engine Manufacturer) Like Suzuki, Toyota, Mercedes etc.

Hope it helps :)

Answer 5

5w30 is better suited for cold weather. It is a lighter fluid, therefore having a lower viscosity than 10w30. To put it simply, 5w30 heats up quicker to reduce friction than 10w30. The less dense the oil, the less time it takes to begin circulating at lower temperatures.

Answer 6

The oil differences have being answered above, the rattling under load in high gears is is 'pinking' caused by low grade fuel, (have you filled up at a different place lately?) or ign. timing (too far advanced) worth a trip to your garage for checking as over being advanced can be harmful to the engine..

Answer 7

A lot of new cars recommend 5w30 year around as it is thinner and will get you more mileage, the close tolerances that engines are built to now will not get proper lubrication if heavier oils are used, always consult and follow your owners manuals recommendations.

Answer 8

10w40 Temperature Range