Automatic trans fluid coolers

[Dommo]

Hi all

I was wondering whether anyone on here had ever fitted or used any automatic transmission fluid coolers? My Soarer ATF is burnt and smells so it's going to be changed and have the filter washed out with petrol, while I was there I was wondering whether to fit a cooler to it. I have read that:
"As a rule of thumb, every 20 degree increase in operating temperature above 175 degrees F. cuts the life of the fluid in half!" (A few sources have mentioned this). 175 degress F is around 80 degrees C, adding 20 degrees F to this gets us to 195 degrees F which is 90 degrees C.. Now the coolant in most cars sits at around 80 degrees C, which is about right in the Soarer which has an 82 degree thermostat. So once the coolant is up to temperature, and assuming the ATF is being WARMED by the heat exhanger during normal driving for instance, the ATF will leave the heat exhanger at a sensible temperature which will increase gradually until it is around 80 degrees C, this is fine.

However once the car gets pushed somewhat, the ATF may then be hotter than the coolant and therefore hotter than 80 or so degrees, at this point it could do with being cooled by the coolant radiator heat exhanger, which is fine in a short thrash as it would soon have adequate time to cool. But what happens on a track day or extended high speed run? My thinking is that the ATF will almost always be above 80 degrees (seeing as the coolant enters the rad at that temperature) unless the radiator is mega efficient at cooling the coolant? Does that seem like a wrong statement to make, anyone?

My plan was to fit a small cooler before the coolant radiator heat exchanger. That way when when the engine is cold, the ATF is 'cooled' by the cooler (but it won't be cooled much at all when everything is cold), before it is then warmed by the coolant radiator/heat exhanger, and once the engine and ATF is up to temperature the ATF will get cooled slightly before going into the coolant rad heat exchanger where it should leave at a fairly optimum temperature.

The ATF cooler I have in mind is nothing big or fancy, it's simply a power steering cooler from a Mondeo V6 my mate bought to strip for bits, it's a U shape that stretches across the length of a coolant radiator, but is fitted with fins on one side of the U, so it wouldn't do much at lower speeds but at higher speeds it should do something, surely?

Any thoughts are much appreciated, I am intending to track this Soarer at least once or twice in it's life hence these plans!

Dom.

[addo]

Get one of the Fleabay B&M copies and splice in with trans cooler flex hose off the roll. No real need for fancy plumbing bits unless they appeal to your inner Barry.

[lexi]

As you know: On an older car the problem with the cooler in rad is that it can clog with metal/debris or contaminate through mixing as innards degrade.
Then kill a transmission. The Mocal type cooler can bypass this . Cold winters may not get fluid to temp quick though

New auto rad and Mocal would be tops......but ££. Sometimes oddball rads come up on Ebay.

[Dippy]

These used to work very well - but I am out of touch with modern stuff

http://www.kenlowe.com/oil-coolers/auto ... nical.html" onclick="window.open(this.href);return false;

[Dommo]

Is the consensus that the U shaped cooler I have wouldn't be enough to bother with? It doesn't have any thin areas on it though it is just one fairly thick pipe, so now I think about it, it might not be worth bothering with. It would be better than nothing though I would have thought..

Ad - my U shaped thing has a fair length of hose on it still which is nice! Are B&M good ones? I figured you Australian types ( ) would have more experience of auto's with the need for a cooler.

Lexi - Is it worth me trying to flush the radiator cooler bit with clean oil if my rad looks in generally good condition? Not sure what the cost would be for a new rad other than 'lots'!! What do you mean 'the Mocal cooler can bypass this', it has the ability to bypass a blockage in the Mocal cooler, or it bypasses the coolant rad alltogether? I'm guessing you mean the second option based on the cold winters comment... I would rather plumb the cooler in before the coolant rad, so that way when the gearbox is cold and engine is warming, the coolant still warms up the oil. It wouldn't if the plumbing was the other way round though as it would get cooled again after the coolant warmed it up..

Dippy - They look alright don't they, shame there's no online prices on there, just to get a rough price more than anything.


Cheers.

[addo]

Trans coolers are a must in countries without real winter. By adding a litre or so of fluid, you are intrinsically adding mileage between changes, too.

Ebay example: http://stores.ebay.com/kkrspeed-perform ... 3479949018" onclick="window.open(this.href);return false;

Stacked plate coolers lose less pressure than "serpentine" coolers for the same volume of fluid cooled. With something like the ones above you would add two -AN to hose barb fittings, and bracket the thing somewhere convenient to shed heat and get a little through airflow. You'd of course delete the OEM cooler at the same time.

[Dommo]

That looks like what I'm after. However I'd like to keep the stock 'cooler' plumbed in as I bet in cold weather the ATF wouldnt warm up. And as far as I understand it, it likes to be around 80 degrees much like engine oil likes to be warm? That's why I'd plumb it in with the aftermarket cooler first. In aus it may be best bypassing the stock radiator/cooler but in the uk I'm not sure it's a good idea.

[addo]

In that case you need two things - a trans temp gauge, and a sandwich type thermostat. The temp gauge may well be able to tee into the sandwich.

I would still flick the OEM cooler as it is extra risk (failure, due to more physical connections) and adds heat to the motor coolant under stress conditions - heat you're now aiming to reject by other means.

[Dommo]

I always thought sandwich type thermostats were for engine oil filter applications? How do you fit one to two flexy hoses?

Cheers

[addo]

You don't have a concentric takeoff on the trans for the cooler lines? Bummer; need to fit an AL4.

Having a read around the 'net suggests that times when the ATF stays cold enough to be a problem, are basically nil. Some of the exxier stacked plate coolers apparently have a couple of passages that allow more fluid flow than the rest, making the passing of slightly thicker (colder) fluid no drama. It may be that knock-offs have got this feature, too.

I don't think it's new enough, but some autos also have a built in thermostatic bypass.

Can't find a viscosity (KV vs Temp) graph for Dex II but honestly would not be worried. it won't sludge up, and you are unlikely to get in and drive off on really icy days without running for a few minutes anyhow - that's just to get some heat in the cabin! Converter slip in this timeframe, will generate plenty of heat.

[lexi]

Adam has covered most of it. Still keep eyes peeled for a new main rad with the cooler. I picked a new one up for a 2.2vtec auto few years back from a parts place.

Expected cheap pattern and it was gen honda and only 60 quid. The Soarer engine may cross over to other Toyota models?

[Dippy]

Dippy - They look alright don't they, shame there's no online prices on there, just to get a rough price more than anything.


Cheers.

There's a link on the menu . sales enquiries.

Kenlowe are a tried and trusted brand , we have had their products fitted to many cars over many years.
Used to be that lots of good car spares shops / garages were agents for kenlow too , don't know now ?