Better fluid = Lower temps... or does it?

[Eskimo]

Disclaimer: I'm not an ME, so anything I'm hypothesising here is straight outta my hindquarters.

I hear people say "I changed to this ATF and my transmission temps are now 10° cooler" or "My oil temps are down 10° after changing to xxxx", or my favorite "My coolant temps are down 10° after adding xxxx additive to my coolant"

In my mind, an engine that's being loaded the same as it was before chaning from X to Y now has more heat trapped in the pistons, the block, etc. if the oil temps are down. Heat is energy, and energy doesn't just go away, or is the reduced heat ACTUALLY because the miracle oil/ATF is that much better at reducing friction of parts?

For water temps after adding Water Wetter or the like, I REALLY have to wonder.. Water's only job is to let heat transfer from the hot parts into the water. The better it does at that job (all other things being equal), wouldn't the coolant temp being warmer show that it's more effectively carrying the heat away from the hot engine parts??

Let's take thermostats out of the equation, as the temp decreases I'm talking about are in race-type applications where any thermostats are already fully open.

 

[chubbs1]

Very good questions and thoughts. I will not comment on Water Wetter or the like because I have no idea how they work...(you made an excellent point. Better oil per se can reduce temps in an engine slightly in reduction of friction, moreso lubes that are slightly thinner at operating temps can transfer heat more quickly. Nothing should be astronomical though. I have a temp gauge and I have noticed some small variations between lubes.

 

[zfasts03]

2003 Z06 corvette ls6 engine

years ago; went from Mobil 1 5w-30 to Amsoil Series 2000 SSO 0w-30 and saw and 18 degree F drop in engine oil temp.

Same driving conditions; went from 217 to 199. Readings were taken at Driver Info Center (DIC) on dash.

Now that series 2000 is no longer available I am running Amsoil ASL 5w-30. Seeing temps around ~203 ish.

 

[bvance554]

I'm not saying that these fluids work... Never heard of an oil that is supposed to reduce temps. However, i think your theory that if the fluid was cooler the. The engine must be warmer may be incorrect. Water Wetter is said to work because it is a better conducter of heat, thus drawing heat away from the engine and out the radiator more efficiently. If a fluid were much cooler than the engine, this would mean it is a poor conducter of heat. I guess a lubricant that reduced friction would mean cooler temps but i doubt it would be measureable.

 

[147_Grain]

A thinner oil is pumped through the engine more quickly and EASIER than a thicker oil - removing more heat from the engine that also doesn't have to work quite as hard (versus a more viscous fluid) to push the oil through the galleys and filter.

 

[Shannow]

Originally Posted By: Eskimo
Let's take thermostats out of the equation, as the temp decreases I'm talking about are in race-type applications where any thermostats are already fully open.


Not dissing your line of questioning, as it's a great set...

However, by ruling out thermostats, and in racing, it falls out of the automotive general topics, where these types of consumer products usually end up in discussion.

 

[meep]

Syn oils are supposefly slightly better at conducting heat. I know it still doesn't answer the heart of the question.... one would have to compare temps internally in multiple locations to see where the heat was, and where it's going. without multiple measurements, everything here will be pure conjecture.

 

[Eskimo]

Originally Posted By: Shannow
Originally Posted By: Eskimo
Let's take thermostats out of the equation, as the temp decreases I'm talking about are in race-type applications where any thermostats are already fully open.


Not dissing your line of questioning, as it's a great set...

However, by ruling out thermostats, and in racing, it falls out of the automotive general topics, where these types of consumer products usually end up in discussion.


True, I was just wanting to take the inevitable "It doesn't matter - the thermostat will keep the coolant at a set temperature anyway" response away..