Deciphering Oil Weights
10-19-2007, 03:34 PM
#1
Three Wheelin'
Thread Starter
Deciphering Oil Weights
what do all those numbers mean.....0,5,10,15 W 15,30,40,50
Anyways...my last oil change was M1 0-W40, and I am going to buy my own oil and bring it to my nech (as he doesnt carry Mobil 1). I cant find 0-W40 for a decent price, so he toild me to just bring 5-W40.....which can be found at wallmart.
Will this be ok?
I dont drive in winter, and dont track my car!
Anyways...my last oil change was M1 0-W40, and I am going to buy my own oil and bring it to my nech (as he doesnt carry Mobil 1). I cant find 0-W40 for a decent price, so he toild me to just bring 5-W40.....which can be found at wallmart.
Will this be ok?
I dont drive in winter, and dont track my car!
10-19-2007, 04:04 PM
#2
Race Car
Join Date: Jul 2005
Location: San Jose Kalifornia Demokratische Republik
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The number before the "W" (0,5,10,15) only comes into effect at cold (Winter) temps, like below zero celsius. HOWEVER, I've heard that a lower 'spread' between the winter and normal numbers is better. I.E. 5-W40 in theory is better than 0-W40 if you don't drive in cold weather.
10-19-2007, 04:40 PM
#3
Instructor
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The numbers relate to viscosity in different temperature environments. You want higher viscosity in hot temps to prevent breakdown in spirited driving. You want low viscosity in cold temps so that the oil can be pressured into every little nook and cranny of your engine as fast as possible to prevent metal-on-metal contact.
Synthetic oils are (generally) better as a lubricant because they (generally) don't include parafins and other waxes that get gummy at low temps. Synthetics also withstand higher temps better as they have better shear strengths (translation: you can push the car harder for longer on a hot day and not have the oil breakdown and lose its lubrication and heat transfer properties).
A tech from one of the local oil companies was invited to talk to our Miata club a few years ago about oils, and he came loaded down with a bunch of graphs and other technical data. He showed us the test results that showed 0Wxx synthetic (in this case, it was Mobil 1 we were discussing) has better high temp viscosity and shear strength than 5Wxx, as well as better low temp flow characteristics. His point to us was that, even though we live in Edmonton with -35C winter temps and +33C summer temps, 0W30 or 0W40 Mobil 1 can be used safely and effectively year round instead of switching oils twice a year to deal with both extremes.
Synthetic oils are (generally) better as a lubricant because they (generally) don't include parafins and other waxes that get gummy at low temps. Synthetics also withstand higher temps better as they have better shear strengths (translation: you can push the car harder for longer on a hot day and not have the oil breakdown and lose its lubrication and heat transfer properties).
A tech from one of the local oil companies was invited to talk to our Miata club a few years ago about oils, and he came loaded down with a bunch of graphs and other technical data. He showed us the test results that showed 0Wxx synthetic (in this case, it was Mobil 1 we were discussing) has better high temp viscosity and shear strength than 5Wxx, as well as better low temp flow characteristics. His point to us was that, even though we live in Edmonton with -35C winter temps and +33C summer temps, 0W30 or 0W40 Mobil 1 can be used safely and effectively year round instead of switching oils twice a year to deal with both extremes.
10-19-2007, 04:48 PM
#4
Three Wheelin'
993MTL - I suggest you do a search on the topic here. There has been LOTS and LOTS of discussion about oil weight, API standards, Zn and P quantity in the oil, etc. Charles Navarro (RL member) has a good article on his website about oil for air-cooled 911 engines. check it out.
10-19-2007, 08:04 PM
#6
Three Wheelin'
Thread Starter
http://www.LNengineering.com/oil.html
As always, if anyone has specific questions, I'm always available by email or a quick phone call away.
As always, if anyone has specific questions, I'm always available by email or a quick phone call away.
my last oil change was M1 0-W40, and I am going to buy my own oil and bring it to my nech (as he doesnt carry Mobil 1). I cant find 0-W40 for a decent price, so he toild me to just bring 5-W40.....which can be found at wallmart.
Will this be ok?
I dont drive in winter, and dont track my car!
10-19-2007, 08:16 PM
#7
Rennlist Member
Although not an approved Porsche oil, the Mobil 1 5w40 (aka Delvac 1) is a better oil, with a higher HTHS viscosity and it also still carries an API SL/CI-4, but this will change within a few months from what I am told.
