Honda Civic Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
266 Posts
Discussion Starter #1
At which temperature does an oil flow better?

There is no temperature where oil suddenly starts to flow better.

A 10W/40 for example will flow between -25C and 100C or more, but there is some difference in the rate of flow! (True viscosity at -25C is about 7000 Centistoke(cSt) units, dropping to 14 at 100C. ‘Viscosity’ is really just another name for ‘rate of flow’.)

The correct question is at what (sump) temperature is an oil at a viscosity that suits a modern high-RPM engine? Present day designs are happy on an oil viscosity of 10 to 15 cSt. (But many are OK on less than 10.) 30cSt is too high at high RPM. It can lead to foaming, air entrainment and cavitation.

Temp. for 30cSt (DegC)..........Temp. for 15cSt ............Temp. for 10cSt

5W/40.........71.............................90.................................117

10W/40.......70.............................99.................................118

10W/50.......80............................109................................130

10W/60.......89............................119................................142


As you will see from the above table a 5W/40 or a 10W/40 is perfectly adequate for all engines except those that run unusually high temperatures (120degC plus)

Cheers
The Opie Oils Team
 

·
Registered
Joined
·
5,006 Posts
For fuel not oil? If it's diesel, then yeah that's fine if you mix it. An old teacher of mine used to do that.

My friend runs a farm and he gets his diesel/petrol dirt cheap. it's a different colour though and if you get stopped you get a fine if you have farm fuel in your non farm vehicle :p
 

·
Registered
Joined
·
4,092 Posts
Alec said:
For fuel not oil? If it's diesel, then yeah that's fine if you mix it. An old teacher of mine used to do that.

My friend runs a farm and he gets his diesel/petrol dirt cheap. it's a different colour though and if you get stopped you get a fine if you have farm fuel in your non farm vehicle :p
Tis True, I used to know someone who worked for a water purifying company and the same crystals that they used to use for purifying water used to take all the dye out of red diesel 8-|
 

·
Registered
Joined
·
7,629 Posts
hi
i think someone is mixing things up intresting oil facts no1 is here http://www.the-corrado.net/forum/viewto ... =1&t=66752" onclick="window.open(this.href);return false; i was wondering when we were getting a second helping i see i am going to have to keep an eye on this ,
my question is were is intresting oil facts no 3 going to be and can you give us all a link to it :)
 

·
Registered
Joined
·
7,629 Posts
Alec said:
For fuel not oil? If it's diesel, then yeah that's fine if you mix it. An old teacher of mine used to do that.

My friend runs a farm and he gets his diesel/petrol dirt cheap. it's a different colour though and if you get stopped you get a fine if you have farm fuel in your non farm vehicle :p
more than a fine customs and excise have the rights to take your car :eek:
 
1 - 16 of 16 Posts
Top