3rdCoastPowerSports

iTrader: (5)

If your coolant temp is 220*f, your oil temp is 220*f and you shut the car off which one will cool down faster?

just a theory question and no fans running after shut down.

ZouMechE

iTrader: (1)

If I'm not mistaken, motor oil will always cool down faster because coolant remains under pressure in the cooling system, while oil does not, so there is essentially nothing to help it retain heat. Any chemists on here to back me up?

lemons12

iTrader: (71)

I would imagine the water/coolant would cool quicker. This is a guess from just thinking about a few things, I have no evidence to back this.

Why are you wanting to know?

lemons12

iTrader: (71)

This makes sense as well..

Alright... I'm 50/50. LOL

ZouMechE

iTrader: (1)

I was thinking of the equation: pressure x volume = n x r x temperature
This would imply that as pressure increases, so does temperature..I think..not sure, always hated chemistry.

3rdCoastPowerSports

iTrader: (5)

Im almost 100% positive that oil cools quicker than coolant. I know oil take longer to heat up but im pretty sure it doesn't retain heat like coolant does.

What about if I just put oil in a pan and coolant in pan then put both in the oven to under the coolants non pressurized boiling point then hit them with an ir and find out.

RealArmyMan

iTrader: (2)

I would imagine that the coolant would lose heat more quickly. It isn't as dense, not to mention, that's its sole purpose...

96capricemgr

iTrader: (1)

how about the coolant in the radiator will cool quicker than the coolant in the block or the oil in the cast oilpan.............................

TheWolfMatt

I'd say that there is really only one way to look at it as there are too many variables to keep things accurate. Take temp readings from several different places, like the radiator, overflow tank, coolant hoses, heater hoses, engine block. Then do the same thing with the oil in the pan, external oil cooler (if you have one), oil filter, etc. It also is dependent on what the weather is like outside, is it hot/cold. Also, are you taking the readings after the engine has been running hard for a while or let idle so it can cool down?

Like I said, too many variables in this equation to really do the math correctly. Thoughts??

Paul Bell

iTrader: (9)

Coolant absorbs heat more easily than oil therefore coolant releases heat better than oil.

Also, in an automobile, about half the coolant in the system is exposed in the radiator allowing it to cool, even without the fans or pump running. The oil is not exposed.

FuzzyDucks

If I remember my heat transfer correctly, I agree with Paul on this one. Coolant is very good at transferring energy via convection, Oil not as good.
The oil drains into the oil pan where there is little air or oil movement to draw energy away from the oil. The coolant continues to flow through the radiator even after the car is shut-off, albeit slowly, thanks to free-convection from heat differentials through and around the radiator, this helps remove energy from the coolant.

ckpitt55

iTrader: (4)

pressure has nothing to do with temperature retention. it has everything to do with what phase the fluid is in and what it's thermal conductivity is. 220 degree water at atmospheric pressure would be steam. the coolant system pressure keeps it in a liquid state, as liquid water transfers heat much more efficiently than water vapor.

in terms of what cools faster, that's dependent on thermal conductivity and the surface area available for convective heat transfer with the air. I think the coolant would win, though it's probably close because the block itself, being aluminum, is a massive heat sink.

96capricemgr

iTrader: (1)

my comment about the coolant in the radiator was based on the ideas a couple posters since have expanded on.
We could throw out that water is technically a better heat conductor than antifreeze so that would suggest the mix ratio would play into the discussion.
What is the thought behind asking this question?
The oil and coolant are BOTH parts of the cooling system.

redtan

iTrader: (5)

I swear it takes FOREVER for the oil to cool down (like say when doing an oil change), but it seems that the coolant temps goes down rather quickly (like when parking for a few minutes and come back to a water temp gauge that has fallen significantly)

Fastdriver1992

iTrader: (1)

Oil cools down much faster then coolant. I run an oil cooler because i run a cement filled block (filled just under the water pump holes) and i run a temp gauge. After a race. The coolant and oil temp are 180-190 degrees. After roughly 20min the oil temp is back down to 100 or less, while the coolant is still around 150. So to answer your question oil cools down faster then coolant.