DEX-COOL, Conventional Green, & G-05... My Experiences

Not quite, but they're related and the effects are almost identical.

Cavitation damage occurs anytime a void (bubble) surrounded by a liquid collapses violently, producing a pressure pulse that can damage metal.

In micro-boiling, the "bubbles" are caused by water flashing to steam and they collapse violently when they migrate into cooler water and the steam re-condesnes almost instantly. This is the "hissing" sound you hear when you heat a pan of water on the stove BEFORE it begins to boil visibly.

In a water pump, the bubbles aren't caused by true "boiling", but are actually caused by the process of cavitation (local reduction in ambient pressure to a point below the vapor pressure of the fluid) caused by the motion of the impeller blades. But when the bubbles collapse, the pressure pulses still erode metal.

Reply to
Steve
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"Steve" wrote

Audi

Audi

Ian

Reply to
shiden_kai

I would still think any liquid in the situation would boil if it got hot enough.

BTJustice

Reply to
Buford T. Justice

Thanks for the information in this and the post 5 minutes before. Good information.

BTJustice

Reply to
Buford T. Justice

Because of that? Don't be silly. Show me 1 mechanic that knows everything. None of them. Everyone has to learn from someone that knows more hopefully. That is where I got that information; from someone who knew more at the time. Someone just posted that the car is an Audi.

BTJustice

Reply to
Buford T. Justice

Am I reading this right? The Audi pumps coolant through the tranny? Learn something new everyday.

"Buford T. Justice"

Reply to
Joe Poitras

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LOL

Reply to
andre

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cooler is mounted on top of the tranny

Reply to
andre

That is the make that "shiden_kai" says does it.

BTJustice

Reply to
Buford T. Justice

Thank you! And why does that NOT surprise me that a company that should have stuck to air-cooled engines would be the one to do it that way? :-)

Reply to
Steve

"Joe Poitras" wrote

It doesn't "pump" coolant through the transmission, it just has coolant pipes running back to a cooler that sits at the rear of the transmission. I know this, because my wife owned an 87 Audi 5000 and I had to do all the repair work on it.

In this case, Audi decided to run coolant back to the transmission, instead of running trans fluid up to the radiator.

Ian

Reply to
shiden_kai

Does transmission fluid really get so hot that the hot engine coolant helps keep it cool?

I'd think that there were better ways to cool a tranny!

Reply to
Phrederik

Approximately 10/8/03 17:05, Phrederik uttered for posterity:

Yes. Particularly under heavy load, which is why transmission coolers are so often part of any heavy duty tow package.

That *could* be politically incorrect.

Reply to
Lon Stowell

Mine didn't like ethanol.

Reply to
TJ 727

But... you CAN overcool an engine and affect performance. Can you overcool a tranny?

Reply to
Phrederik

Not really. There's no source of moisture or volitiles to contaminate auto tranny fluid as there is in an engine (combustion blow-by) so unless you make a habit of fording streams, you don't need the oil to get hot to drive away accumulated moisture.

I suppose that if you lived in a VERY cold climate and, for example, your transmission fluid never got above freezing, you might have a problem. But as long as it gets to "room temperature" I'd think it should be fine.

Reply to
Steve

Some transmissions will not lock the torque converter untill they see a certain trans fluid temp. So I'd have to say yes, it is possible to overcool a transmission. Bob

Reply to
Bob

My Saturn SL2 won't shift into 4th gear until it reaches an operating temperature on cold days. So, on really cold days, the engine rpm's can get up there in the morning commute.

later,

tom

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Reply to
junkmail01

Ensure it will handle the pressure.

ATF coolers don't run at nearly the pressure that engine oil does.

Reply to
Stephen Bigelow

I think it is actually going into 4th gear and it's the torque converter lockup that you are not feeling. They let the converter slip to purposely build heat in the trans until it comes up to operating temp. Bob

Reply to
Bob

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