what grade oil
Instructor
Joined: Feb 2006
Posts: 205
Likes: 0
From: Fraser MI
What grade oil
Ok, here's what the deal is on a can of oil.
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
I'm currently running Castrol GTX synthetic 10w-30 in my '85 and it runs great. Next oil change i'll be putting 5w-30 in though cause it'll be warmer out. You should use 10w-30 if it regulary drops below freezing in your area like in the winter time, unless of course you dont drive it in the winter. However, 5w-30 wont hurt it in the winter.
Instructor
Joined: Feb 2006
Posts: 205
Likes: 0
From: Fraser MI
oil capacity
4Ever21,
You have it reversed. If you insist on using different wt oils
in different seasons use the 5W-30 in the winter and 10W-30
in the summer.
The lower W # is best in cold temps.
Craig
You have it reversed. If you insist on using different wt oils
in different seasons use the 5W-30 in the winter and 10W-30
in the summer.
The lower W # is best in cold temps.
Craig
Burning Brakes
Joined: Jun 2005
Posts: 861
Likes: 1
From: Hyde Park NY
St. Jude Donor '05
Originally Posted by Craig's Polo '93
Ok, here's what the deal is on a can of oil.
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
NOw this is the best answer on this question I have seen yet.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Jun 2000
Posts: 1,148
Likes: 48
Originally Posted by Craig's Polo '93
Ok, here's what the deal is on a can of oil.
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
5W, is what the oil will flow like when cold.
30, is the grade that the oil reaches when hot, usually
measured at 100 degrees C.
As long as the latter # is the same both oils will
protect the same when hot. The 5W will flow better
than the 10W at startup when cold because it has
less viscosity and is more pumpable.
Therefore IMHO the 5W is a superior oil for that reason.
I like 0W even better.
We can go waaaay further into this comparine "borderline
pumpability", amount of viscosity improvers, yada, yada, yada.
For extremly fascinating (to some) discussions on oil go to:
http://www.bobistheoilguy.com
These folks are beyond **** and I believe even drink oil
upon occasion. Great site.
Craig
Why does 20W50 oil create higher oil pressure@operating temp than 0W50?
Instructor
Joined: Feb 2006
Posts: 205
Likes: 0
From: Fraser MI
grade oil
VetteThreat,
Great question. Oils reach a certain wt by either having that weight
base stock, (the oil itself), or by having VII additives (viscosity index improvers) that bring the oil to that wt in the presence of heat.
The VII's provide the protection of a certain wt, say 50 in this
example while having a lesser base stock wt. VII's are polymers
that thicken and expand in the presence of heat. My favorite
example is like what spagetti does after you boil it. Gets longer
and fatter. VII's return to their original size when the oil cools.
So when you pour in a can of straight 50 it will be thicker and
more viscous than pouring in a can of 20W-50
Pressure is really a sign of "resistance to flow" of which viscosity
of the fluid is a major factor. VII's provide a lesser wt oil more
protective wt when hot, not necessarily more "thickness".
Hence the differences in oil pressure.
Problems in the early days of additive chemistry and cheap VII's
today is that they "shear back". This is the breaking of the polymer
chain under stress and making the spagetti (rotini is a better example) chains shorter hence offering less size and protection
against metal to metal contact and causing what is called
"boundry lubrication".
This is the best answer as I conceive it.
Craig
Great question. Oils reach a certain wt by either having that weight
base stock, (the oil itself), or by having VII additives (viscosity index improvers) that bring the oil to that wt in the presence of heat.
The VII's provide the protection of a certain wt, say 50 in this
example while having a lesser base stock wt. VII's are polymers
that thicken and expand in the presence of heat. My favorite
example is like what spagetti does after you boil it. Gets longer
and fatter. VII's return to their original size when the oil cools.
So when you pour in a can of straight 50 it will be thicker and
more viscous than pouring in a can of 20W-50
Pressure is really a sign of "resistance to flow" of which viscosity
of the fluid is a major factor. VII's provide a lesser wt oil more
protective wt when hot, not necessarily more "thickness".
Hence the differences in oil pressure.
Problems in the early days of additive chemistry and cheap VII's
today is that they "shear back". This is the breaking of the polymer
chain under stress and making the spagetti (rotini is a better example) chains shorter hence offering less size and protection
against metal to metal contact and causing what is called
"boundry lubrication".
This is the best answer as I conceive it.
Craig
Drifting
Joined: Jun 2002
Posts: 1,945
Likes: 41
From: Corinth TX
This was posted in the C5 section recently. The article contains alot of good information. It really answers alot of questions that you may have and alot of answers that you didn't know you had questions for. 
It actually made me sleepy reading alot of it. Hope it helps.
It actually made me sleepy reading alot of it. Hope it helps.
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
Originally Posted by NocarbutaVetteforme
This was posted in the C5 section recently. The article contains alot of good information. It really answers alot of questions that you may have and alot of answers that you didn't know you had questions for. It actually made me sleepy reading alot of it. Hope it helps.
It actually made me sleepy reading alot of it. Hope it helps.
Race Director
Joined: Jul 2004
Posts: 16,795
Likes: 62
From: Lake Havasu City, AZ
5W30 will give better lubrication on start-up ( less wear) , better fuel economy and more Horsepower than a 10W30 motor oil.
0W30 will give the same improvements over 5W30.
As long as the oil meets or exceeds the minimum API specs for your car you are fine. I don't think you can find any multigrade on the US market that is not better (exceed) the API specs that were in place when your C4 was built.
0W30 will give the same improvements over 5W30.
As long as the oil meets or exceeds the minimum API specs for your car you are fine. I don't think you can find any multigrade on the US market that is not better (exceed) the API specs that were in place when your C4 was built.
Burning Brakes
Joined: Apr 2000
Posts: 980
Likes: 2
From: Chandler AZ
I have often wondered
What temperature is the cold rating done at? If it is 0°C then in Arizona in the garage it wouldn't matter. If it is 40°C then it might be another issue whether one would run 5W30 or 10W30.
Burning Brakes
Joined: Jun 2000
Posts: 1,148
Likes: 48
Bottom line, 20W50 oil is thicker than 0W50 at ALL temperatures as is 10W30 vs 0W30.
Don't believe me? Okay, tell me then: Why after many years do we still have 10W30 oils available if 5W30 oil would have the same protection hot yet better flow when it's cold?
Don't believe me? Okay, tell me then: Why after many years do we still have 10W30 oils available if 5W30 oil would have the same protection hot yet better flow when it's cold?
Instructor
Joined: Feb 2006
Posts: 205
Likes: 0
From: Fraser MI
oil
Because there's still a market for 10W-30. Getting people to
change to somthing that has a lower #, even though a superior
product is not easy. More is better right? So there is still
demand for 10W-30.
Takes a long time for the uneducated public to change especially
when nothing bad happened when using the older product.
The current uproar about 5W-20 is an example about the same
issue.
Thin is in.
Craig
change to somthing that has a lower #, even though a superior
product is not easy. More is better right? So there is still
demand for 10W-30.
Takes a long time for the uneducated public to change especially
when nothing bad happened when using the older product.
The current uproar about 5W-20 is an example about the same
issue.
Thin is in.
Craig
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
You have to look at the Product Data Sheets for the oils, specifically at the 100C cSt value, to see which oil is thicker when hot.
Pages below show that Mobil 1 10W-30 is thinner hot than either the 5W-30 or the 0W-30 Mobil 1. The German Castrol Syntec 0W-30 is thicker hot than all of the other 30 weights listed.
http://www.mobil.com/USA-English/Lub...bil1_0W-30.asp
http://www.mobiloil.com/USA-English/...bil1_5W-30.asp
http://www.mobil.com/USA-English/Lub...l_1_10W-30.asp
http://www.castrol.com/liveassets/bp...syntec_usa.pdf
Pages below show that Mobil 1 10W-30 is thinner hot than either the 5W-30 or the 0W-30 Mobil 1. The German Castrol Syntec 0W-30 is thicker hot than all of the other 30 weights listed.
http://www.mobil.com/USA-English/Lub...bil1_0W-30.asp
http://www.mobiloil.com/USA-English/...bil1_5W-30.asp
http://www.mobil.com/USA-English/Lub...l_1_10W-30.asp
http://www.castrol.com/liveassets/bp...syntec_usa.pdf
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by VAHROOM
What temperature is the cold rating done at? If it is 0°C then in Arizona in the garage it wouldn't matter. If it is 40°C then it might be another issue whether one would run 5W30 or 10W30.
