OT Cars, Radiator, Oil Cooler, Honda,

[micky]

Friday maybe, on the People's Court, a transmission mechanic said that the customer's car had leaked at the engine thermostat, he'd lost a lot of antifreeze, and the antifreeze cooled the transmisson fluid, so the transmission overheated and needed 200 dollars worth of parts (he said he didnt' charge for labor.)

I don't pay much attention to these parts because afaik every water cooled car on earth with an automatic transmission works the same way. That is, the engine cooler and transmission cooler are on the same brackets, but they are totally unrelated to each other. I've never seen a supplementary oil cooler, like with a trailer package, but I figure it's even more! true for that.

IOW, the mechanic was lying. Is my impression of the way all cars are made correct? Was the mechanic lying?

[Stormin Mormon]

My 1995 Chevrolet work van has a transmission cooler line that goes into the radiator (glycol filled radiator) and back to the transmission. The two fluids do not mix, the TX cooler line goes through the bottom of the green glycol. So, in my one vehicle a loss of glycol antifreeze might contribute to TX over heating. My

1998 Blazer also has TX cooling line that goes in and out of the radiator. I side with the mechanic.

[clare]

It's how MOST automatic transmission cars work, but auxilliary oil coolers are direct oil to air coolers - and what makes you say he was lying???

[David L. Martel]

Micky,

I agree with Stormin. Most likely the transmisiion cooler is built into the radiator. When the radiator coolant fails the transmission cooler won't work. This combined radiator is quite common.

Dave M.

[Terry Coombs]

I think it might be the part about "the customer's car had leaked at the engine thermostat, he'd

Which was probably misunderstood by the customer . HOWEVER this time Chris is right , in most vehicles the tranny oil is cooled by a heat exchanger in the radiator , lose coolant and both the motor and tranny overheat . Some vehicles will have a direct air/oil cooler in addition or instead of the in-radiator unit .

[clare]

If properly installed it will ALWAYS be in addition to. It takes a HUGE auxilliary cooler to equal the effect of the radiator mounted (integrated) cooler.

[Tegger]

micky wrote in news: [e-mail]:

He's not likely to be lying..

As pointed out by others, the transmission oil cooler is inside the bottom tank of the radiator. Heat exchange is completely dependent on coolant flow, which is created by the engine's water pump.

If the coolant level is allowed to get too low, the pump will have insufficient "bite" on the fluid to be able to push it around, and either or both engine and transmission will eventually overheat. And it will be the tranny that feels it first. Overheating is a primary cause of automatic transmission failure.

[clare]

Even worse yet - when's the last time you saw a rad with a "bottom" tank - particularly on a Honda?The heat exchanger is vertically mounted in the SIDE tank - and as the water level drops more and more of the cooler is exposed to mostly (hot) air instead of coolant, so the trans can overheat while the engine still gets enough cooling to prevent melt-down.

[Tony Hwang]

Hi, When I had F250(trailer towing special) with 30' 7000 lbs. fiver, I installed aux. cooler in series with original cooler. Mind you the rad. was heavy duty one too. Any how I never exprienced over heating running around in the Rockies during summer month. I know tranny oil running to cool is bad too. I have ??? on this "leaked at the engine thermostat" This sounds funny.

[Tony Hwang]

Hi, Any how good thing head gasket did not blow?!...

[clare]

Running too cool is generally not an issue if you keep the rad cooler installed - idiots that bypass the rad cooler are just asking for trouble, IMHO.

As for the leaking at the thermostat - lots of DIYers, and even a fair number of "mechanics" damage the thermostat housing when replacing thermostats - or just screw up the gasket installation.. Or the hose is a bit loose at the thermostat housing, causing a very slow seepage leak