Auto Trans cooler on compact car
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My '03 Toyota Echo comes with a factory ATF cooler integrated in the radiator. Toyota engineers must see some merits for it to be there.
I may be wrong...but i think every automatic comes with some type of cooler, but the additional ones make a big difference.
On a 95F day my ATF temp will reach 180F when stuck in a traffic jam. But on a 32F day it won't even register at 100F after driving for 1 hour and 10 minutes over 35 mile distance to work one way. Additional cooler may be beneficial in summer, but definitely not in winter. ATF has to reach certain temp for AT to operate smoothly.
I'm in Houston. Every auto car I have gets a cooler, as there's no way I can get it TOO cool. If you were in sub-zero or just above zero temps, then maybe. If I were in a typically cold climate, I might put a small aftermarket cooler BEFORE the fluid gets to the radiator "cooler". Keep in mind that the trans temp will be roughly what the coolant temp is, which would be maybe 180-190 on your average newer car. IF the trans temps had climbed significantly (towing, etc), then it would get to the point where the in-radiator cooler wouldn't be able to remove enough heat. That's where the aftermarket cooler would come in. Where I am, it's so hot that I put the biggest stacked plate cooler AFTER the radiator. Therefore, the radiator cooler somewhat stabilizes the temp near coolant temp. After that, the cooler can try to drop it another 10-15 degrees in my experience. Sometimes it's hard to keep it under 200-210 degrees, which is about the highest you want the transmission fluid temp to get.
EDIT: That 180-190 degrees on coolant temp will be on the cold side of the radiator, which, conveniently enough, is where the trans cooler is in the radiator.
Ditto what Earl posted...
I remember reading with my B&M stacked plate design that it has a bypass of some sort if the fluid gets too cold so using it in the winter does not matter. I have three blazers two of the aftermarjet coolers are after the radiator, and in my old 92, it only has the aftermarket cooler due to a leaking transmission cooler in the radiator. All work fine in the summer and winter up here in Michigan. If you are conserned about the fluid being too cold in the winter an old license plate in front of the aftermarket cooler will help warm up thye fluid in the winter.
I like the aftermarket ATF coolers too. The factory 'in radiator tank' coolers are sometimes don't always have enough heat rejection capacity.
What makes you say that?
Agreed!!!~~ I wouldn't own a vehicle without an external cooler, no matter the size or climate.
When my Police Interceptor went home with me, after is was taken out of duty, I replaced the factory transmission cooler, with one rated for a 30,000 pound vehicle!
I have an AAMCO on the corner, that has had the same family running it for over 40 years. A couple of the mechanics have been there since day one, and have seen it all. They say it's hard to get a transmission "too cool."
The stacked-plate type coolers are WORTH the extra $$$, over the cheaper Tube & fin. By-pass valves allow the plate types to warm to a proper temp in winter, while preventing higher rates of damaging heat.
That being said, if a tube & fin style is all you end up with, it's better than none at all, by a great margin. Every little bit helps...
I was just throwing numbers, but I don't think I'm far off. A car running a 195 degree thermo (about the hottest I know of) will have the average coolant temp at least 5 to maybe 10 degrees under the rated temp. The coolant temp, after going through the radiator, should be at its coolest point in the system. I don't think my off-the-cuff numbers are too far from reality. What say ye?
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Sounds about right. The lower end of the rad is probably 15-20F cooler then the coolant leaving the engine (vertical flow rad). On the cross flows, assuming it only has a trans cooler, they usually put it on the outlet tank and, IIRC, run it counter current to the flow. That is, the hottest ATF enters the bottom and exits the top.
Most of the in-radiator coolers have the transmission fluid passages in contact with the radiator coolant. Others give the transmission fluid it's own area in the radiator, like the upper few rows. A while back I was reading about a new car that had it's transmission cooler like the latter, I beileve it was a Dodge Charger. I would think this method would allow for increased cooling.
On older cars I've worked on, I only ran an external cooler, as most do it this way. But these are usually just fair weather vehicles. If I were to put one on a late model vehicle, I'd probably put it after the factory radiator.
On older cars I've worked on, I only ran an external cooler, as most do it this way. But these are usually just fair weather vehicles. If I were to put one on a late model vehicle, I'd probably put it after the factory radiator.
I fully agree that overheating is detrimental to a transmission.
However, if it remains too cool you may lose fuel saving features in some transmissions like torque converter lock up.
Nissans I have been in do not lock up the TC until the transmission has warmed (I do not know the target temperature). In summer it only takes about 2 miles. At mere freezing ambient temperature (car parked outside) it takes 6 miles to warm enough for TC lock up.
However, if it remains too cool you may lose fuel saving features in some transmissions like torque converter lock up.
Nissans I have been in do not lock up the TC until the transmission has warmed (I do not know the target temperature). In summer it only takes about 2 miles. At mere freezing ambient temperature (car parked outside) it takes 6 miles to warm enough for TC lock up.
SO, with all this talk of coolers - recommendations?
Where to buy?
Brands?
Where to buy?
Brands?
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I've never done too much research on this ..but I think that the converter doesn't lock up until the engine coolant reaches a preset temp. The first source that I came to that, more or less, confirmed my "belief". aka ..it agreed with my take on it so far
I'm sure there's exceptions to both. That is, YMMV
..BUT..I've never heard of anyone throwing on a cooler complaining about delayed lockup.
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What are you driving? How big? Anything is an improvement.
Ebay can be your friend here.
I've run B&M from SummitRacing.com, and I've run parts-store Hayden stacked plate coolers. I think they're made in the same plant. I run the biggest one that'll fit, as I don't have to worry about the cold in Houston (except RIGHT NOW, when we've got ice on the roads). As states, if it's that cold, just put something in front of it like a piece of cardboard to block the air flow. It would have to be awfully #@$%! cold for the cooler to keep the fluid cold enough to affect shifing and torque converter lockup!
Quote:
I've never done too much research on this ..but I think that the converter doesn't lock up until the engine coolant reaches a preset temp. The first source that I came to that, more or less, confirmed my "belief". aka ..it agreed with my take on it so far
I'm sure there's exceptions to both. That is, YMMV
..BUT..I've never heard of anyone throwing on a cooler complaining about delayed lockup.I've heard of some super heavy duty diesel pickups waiting for a substantial amount of time/mileage for lockup when driving in cold weather with NO LOAD.
Gary, thanks for the clarification. It is good to know that adding a trans cooler should not delay TC lock up.
The dash temperature gauge reaches normal operating temperature in about half the time it takes for the TC lock up to begin functioning, thus I thought the TCU was monitoring the transmission temperature instead. I realize the dash temp gauge is not precise, but is the program monitoring a different temp sensor than the one driving the dash gauge?
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