Oil cooling questions... lots of them...

[Default]

I might as well just list them:


- How does oil cooling work?
- Does oil cooling constantly work or does it only kick in when the oil has surpassed a certain temperature?
- What are the benefits/disadvantages of oil cooling?
- I have heard rumors that BMWs with the S54 engine are equipped with oil cooling, while the S52s are not, is this true?
- How come there are cars out there like the Ford Explorer that have transmission oil cooling, but most (if not all) BMWs do not have it?
- Why are there high-performance cars out there that do not have oil cooling and then there are others that do?

 

[wood_e]

Are you asking about transmission oil or engine oil?

Oil cooling can work in several ways. Some have an in-line thermostat that opens up at a certain temperature while others just keep circulating the oil no matter what temperature it is.

The benefits are that your oil, whatever it is will not break down as quickly and it may maintain a lower temperature. However you are more prone to leaks.

The ford explorer has a transmission cooler because they sometimes have to tow things. Towing really heats up transmissions and heat is the main reason of transmission failure in cars.

I really can't field the other questions with justice...

 

[Default]

Are you asking about transmission oil or engine oil?

Oil cooling can work in several ways. Some have an in-line thermostat that opens up at a certain temperature while others just keep circulating the oil no matter what temperature it is.

The benefits are that your oil, whatever it is will not break down as quickly and it may maintain a lower temperature. However you are more prone to leaks.

The ford explorer has a transmission cooler because they sometimes have to tow things. Towing really heats up transmissions and heat is the main reason of transmission failure in cars.

I really can't field the other questions with justice...

Engine mostly, I was just wondering why the Explorer had an oil cooler and most high performance cars don't.

 

[wood_e]

Engine mostly, I was just wondering why the Explorer had an oil cooler and most high performance cars don't.

Engine oil cooling is mostly to keep the thermal breakdown to a minimum. Usually the more oil you have the harder it is to break it down. "Air" cooled porsches were really oil cooled. Most cars take 5 quarts of oil, those took in upwards of 12 quarts.

The explorer to my knowledge has a transmission cooler... it also may have an oil cooler that cools the oil with anti-freeze.

FWIW my SHO has an oil cooler that is cooled via anti-freeze as well and I bet most cars actually have them or some simmilar device to aid in cooling. Many don't have external oil coolers though...

 

[Tom]

I agree with wood_e.

The reason why some cars have external/auxiliary oiling cooling systems is due to inadequate radiator capacity. This could be from having an insufficient radiator size due to lack of space, running extra boost on a force induction engine, or having a high compression engine like the S54 motor.

Just think of the oil cooler as another radiator, it uses the car's coolant system to warm the oil as well as keeping it cool. The oil would exit the filter and pass through the cooler before it re-enters back in your engine.

The S54 has a slightly differnt setup, it uses cool air instead of water to cool down the oil, but the process is still very similar.

 

[mjbst111]

all automatics have transmission oil coolers.

I guess its kind of general statement but i have yet to see an automatic without transmission oil lines that go to and share the coolant radiator.

That is why when you order a radiator they ask you if you have an automatic.

 

[poboyis]

"Air" cooled porsches were really oil cooled. Most cars take 5 quarts of oil, those took in upwards of 12 quarts.

you only got out 12 quarts when you changed it, the entire systen holds somewhere between 20 and 30 if i remember right

 

[wood_e]

you only got out 12 quarts when you changed it, the entire systen holds somewhere between 20 and 30 if i remember right

Ah I might be off. My dads 79' SC he said it was like 12 quarts, I don't think he knows though...

 

[Default]

you only got out 12 quarts when you changed it, the entire systen holds somewhere between 20 and 30 if i remember right

30 quarts? That's insane.

So the S54's oil cooling is some sort of an air-cooled system?

 

[poboyis]

no, i was talking about Porsche.

Some cars have an engine oil cooler. often times it is because of higher engine temps, BMWs tend to run a lil bit hotter, so the factory puts an oil cooler on them. Automatic transmissions have tranny fluid coolers. sometimes it is a separete, finned cooler, sometimes it is just a cooler that is built into the radiator, they work best when used together. manual trannys do not have a cooler because there is no way to pump the fluid, it jsut basically gets splashed all over everything. an auto has a pump that is turned by the torque converter. Heat is the #1 killer of auto trannys, so they did the smart thing and do what the can to cool it off a bit.

 

[aNoodle]

no, i was talking about Porsche.

Some cars have an engine oil cooler. often times it is because of higher engine temps, BMWs tend to run a lil bit hotter, so the factory puts an oil cooler on them. Automatic transmissions have tranny fluid coolers. sometimes it is a separete, finned cooler, sometimes it is just a cooler that is built into the radiator, they work best when used together. manual trannys do not have a cooler because there is no way to pump the fluid, it jsut basically gets splashed all over everything. an auto has a pump that is turned by the torque converter. Heat is the #1 killer of auto trannys, so they did the smart thing and do what the can to cool it off a bit.

Well said!! My E46 has lines out of the auto tranny to a seperate radiator attached to the main radiator.

 

[jrt67ss350]

Well said!! My E46 has lines out of the auto tranny to a seperate radiator attached to the main radiator.

It's not unique to your car or BMWs - ALL cars with automatic transmissions have at least a radiator cooler built into the radiator. This has been true ever since autos became mass-producible. Without a fluid cooler, auto transmissions get very hot because they basically work on the premise of slippage - the torque convertor is constantly "slipping" except when the lockup solenoid is engaged - this creates an immense amount of heat (yes, I know that is a huge oversimplification).

In addition to the stock tranny oil cooler in my Camaro, I have removed the lower inspection cover over the torque convertor - exposing the turning torque convertor to the undercar air stream lowers transmission temps about 25-50 degrees. A cool transmission is a happy transmission, particularly if it is driven hard.