10w 30 oil

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kpack

Joined
Mar 25, 2016
Messages
6
Location
Bryan Texas
If I understand this right 10w is when the oil is cold and the 30 is the viscosity when it’s at operating temperature, let’s say 190 degrees.
My question is how long does the oil stay at 10 .
My truck probably takes 6 miles to get the temp all the way up.
 
The 10W is how the oil acts in cold temperature, oil cannot thicken when warming up, although it would be cool, physically it cannot work that way.
30W is how it acts when the engine is at operating temperature.
 
kpack said:
If I understand this right 10w is when the oil is cold and the 30 is the viscosity when it’s at operating temperature, let’s say 190 degrees.
My question is how long does the oil stay at 10 .
My truck probably takes 6 miles to get the temp all the way up.
Click to expand...

The number in front of the W is the "Winter" rating of the lubricant, it does not correspond to a viscosity figure, it simply means that the oil is able to pass the two viscosity limit tests for that Winter rating. These tests are:

1. CCS - Cold Cranking simulator - This measures the impact the oil has on cranking speed. This has a lower limit and is measured 5C higher than the 2nd test
2. MRV - Mini Rotary Viscometer - This measures the ability of the oil tp be pumped. This has a much higher limit and is measured 5C lower.

The number after the W is the SAE grade of the lubricant when hot, measured at 100C.

You can see the Winter rating limits as well as the hot viscosity ranges in SAE J300:
sae-j300-motor-oil-viscosities.jpg
 
Castrol claims that their research shows that it takes about 20 minutes for the sump oil to come up to full operating temperature. It is during this time frame that most of the wear occurs. They have papers written on this topic and of course there are numerous advertisements for their Magnatec product that is specifically designed to protect engines during this warming up period.
 
FowVay said:
Castrol claims that their research shows that it takes about 20 minutes for the sump oil to come up to full operating temperature. It is during this time frame that most of the wear occurs. They have papers written on this topic and of course there are numerous advertisements for their Magnatec product that is specifically designed to protect engines during this warming up period.
Click to expand...

The time that it takes the sump to come up to temperature varies massively by design, the presence of coolant/oil heat exchangers, sump volume...etc. There is no universal figure. Both my vehicles have coolant/oil heat exchangers but my wife's truck comes up to temp MUCH faster than my SRT. Both take less than 20 minutes. My old M5 would take forever to come up to temp in comparison, as it had a massive thermostatically controlled oil cooler.
 
Oil starts out thicker when cold, the higher the “W” number, the thicker it is. Pour point depressants help, but even the upper number has an effect on cold temperature performance & flow too. A fully synthetic SAE 30 (like the Amsoil HDD 30) can flow better at colder temperatures than a conventional 10W30. When a multi-viscosity oil gets hot, the viscosity index improvers help keep the oil thicker than it otherwise would be at high temperature, although the VIIs can shear with use & cause thinner oil & potential sludge.
 
kpack said:
If I understand this right 10w is when the oil is cold and the 30 is the viscosity when it’s at operating temperature, let’s say 190 degrees.
My question is how long does the oil stay at 10 .
My truck probably takes 6 miles to get the temp all the way up.
Click to expand...
It means if you live in a hot part of Texas where it never gets below 50 degrees...... you can use any weight oil you like.
 
OVERKILL said:
The time that it takes the sump to come up to temperature varies massively by design, the presence of coolant/oil heat exchangers, sump volume...etc. There is no universal figure. Both my vehicles have coolant/oil heat exchangers but my wife's truck comes up to temp MUCH faster than my SRT. Both take less than 20 minutes. My old M5 would take forever to come up to temp in comparison, as it had a massive thermostatically controlled oil cooler.
Click to expand...


True indeed ^^^^^

The lady's 98 Camry takes a LONG time to warm up. My car takes way, way less time vs her Camry. My car maybe 10 minutes. Her car is at least 20 minutes and cold enough... 25+ minutes.
 
10W30 flows like a cold 10W on cold start-up and a 30W at temp...the former being much slower/thicker cold than the later when warm....a straight 30W30 would be much slower/thicker on a cold start.
 
dblshock said:
10W30 flows like a cold 10W on cold start-up and a 30W at temp...the former being much slower/thicker cold than the later when warm....a straight 30W30 would be much slower/thicker on a cold start.
Click to expand...

Please see my explanation earlier in the thread.
 
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