OEM Trans Cooler Install?

Messages
96
Location
Maine
2013 Taurus, 270k miles. I'm adding an OEM (PI option) cooler to the car since it's lasted this long, I figure why not help it a bit more? Anyway I have some concerns.

1. I can't tell which line from the trans into the radiator is hot/out, and cool/in. Does it matter where either line goes? Only difference is one is above the other. Both in/out ports on the cooler are on the bottom which is confusing me..

2. The factory cooler is WAY smaller than the radiator. Will bypassing the radiator altogether and only using this cooler affect it negatively, especially in traffic and/or hot weather?

I can post photos if needed. I've looked around but can't find answers to these specific concerns.
 
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Messages
2,260
Location
Seattle-ish, WA
a) which line? two ways to figure this, neither complicated
  1. Trace the lines from the cooler back to the transmission. The return line is going to join just above the pan. The output line is going to originate somewhere about mid-height near the bell-housing (usually).
  2. Just pull a line and crank a second, with a hose attached or catch-pan. You'll figure out which line it is immediately. ;) And yes, it matters which one you use as you don't want the OE cooler re-heating cooled fluid; don't put the aux cooler in the trans output line before the OE cooler.
b) I would (have) always plumb(ed) the aftermarket cooler in series with the factory one, and downstream. Maximum cooling. Even in single digit temps, my vehicles show a "floor" trans temp in the low 100F range. You'll get maximum cooling, and you'll get warming benefit of the radiator in cold conditions w/o a huge penalty.
 
Messages
25,433
Location
MA, Mittelfranken.de
2013 Taurus, 270k miles. I'm adding an OEM (PI option) cooler to the car since it's lasted this long, I figure why not help it a bit more? Anyway I have some concerns.

1. I can't tell which line from the trans into the radiator is hot/out, and cool/in. Does it matter where either line goes? Only difference is one is above the other. Both in/out ports on the cooler are on the bottom which is confusing me..

2. The factory cooler is WAY smaller than the radiator. Will bypassing the radiator altogether and only using this cooler affect it negatively, especially in traffic and/or hot weather?

I can post photos if needed. I've looked around but can't find answers to these specific concerns.

Plumb it in series with the radiator installed one. In Maine it will also help get the fluid up to temp or help maintain it in very cold weather. If using the external cooler only make sure it has a thermostat in the system somewhere, it may have an OE one or you may have to add one.
 

Rochev

Thread starter
Messages
96
Location
Maine
Thanks for the info guys! I attached some pics. The new factory cooler is installed under the bumper, you can see the two connections located only on the bottom, so I assume it doesn't matter where I put the return line since it'll be cooled just the same?

And if I utilize the radiator, which is what I want, I run a return/cooled line from the radiator, to the aux, and then back to the trans...? Just making sure, as I'd hate to be the one to ruin it at so many miles
 

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Messages
1,439
Location
Indiana
Plumb it in series with the radiator installed one. In Maine it will also help get the fluid up to temp or help maintain it in very cold weather. If using the external cooler only make sure it has a thermostat in the system somewhere, it may have an OE one or you may have to add one.
Agree. FWIW can you find the factory parts book illustrations to show the OE routing, or find one in a salvage yard?
 
Messages
25,433
Location
MA, Mittelfranken.de
Thanks for the info guys! I attached some pics. The new factory cooler is installed under the bumper, you can see the two connections located only on the bottom, so I assume it doesn't matter where I put the return line since it'll be cooled just the same?

And if I utilize the radiator, which is what I want, I run a return/cooled line from the radiator, to the aux, and then back to the trans...? Just making sure, as I'd hate to be the one to ruin it at so many miles

The second pic looks like the thermostat.
 

Rochev

Thread starter
Messages
96
Location
Maine
I set it up. However, the fluid coming back out of the new aux and into the transmission-it wouldn't make its way up the hose. Just kept bubbling and not going higher than half way up.
The fluid going out of the radiator leading down to the new aux was also barely moving and not filling the width of the hose.

Is this because the fluid is cold and taking time to run through both radiators, or should the fluid be pushing through the lines quickly? I ran it for a minute with no change. When I pulled the lines to find the trans-out one, the fluid came down the hose pretty quick.
 
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Messages
25,433
Location
MA, Mittelfranken.de
If the thermostat for the oil cooler is closed as it is supposed to be until the fluid comes up to temp it will not go through the lines to the cooler. Get the fluid up to temp and see what you have then, it should be flowing freely.
 
Messages
26
Location
AZ
I just added an aux cooler for my 4th gen 4runner.
1. Consensus is to connect it in series after the stock cooling circuit.
2. Best way to be absolutely sure on what hose to use is to disconnect one hose at the radiator. To keep from making a mess, I use clear tubing, connect one tube to the radiator, and another with a splice to the loose hose end. Route both tubes to an oil drain pan and run your car for a few seconds. The tube with oil in it will tell you which way the fluid is coming and going.
 

Rochev

Thread starter
Messages
96
Location
Maine
Bronx, that's exactly what I did to figure out the line routing. Super easy way to know for sure. I figured it'd have to generate some heat before flowing, but I did drive it an hour today, 85+ degrees out and when I got home I checked the return line from the aux and it was empty again. I did see fluid moving through it yesterday. I know I'll get a message it the trans is getting too hot. I don't see how there could be an issue so I'll just keep checking on it to make sure.
Thanks to everyones input!
 
Messages
25,433
Location
MA, Mittelfranken.de
Bronx, that's exactly what I did to figure out the line routing. Super easy way to know for sure. I figured it'd have to generate some heat before flowing, but I did drive it an hour today, 85+ degrees out and when I got home I checked the return line from the aux and it was empty again. I did see fluid moving through it yesterday. I know I'll get a message it the trans is getting too hot. I don't see how there could be an issue so I'll just keep checking on it to make sure.
Thanks to everyones input!

Try moving the lines from the radiator to the thermostat, I am guessing it only works one way.
 

Rochev

Thread starter
Messages
96
Location
Maine
Trav-
I'm not trying to be a dud but I'm not sure what you mean. Both lines join together through the t-stat and go right to the radiator. The only thing I know for sure is the hoses are in the right place. It's been driving fine, doesn't seem to be too hot. I'm thinking its not continuously sending fluid back out the radiator as that line sometimes has some fluid and sometimes is dry. However, a foot length of the hoses to and from the aux cooler are always full. Just the section of the return line out of the radiator is suspect, unless it's not continuously flowing.
 
Messages
25,433
Location
MA, Mittelfranken.de
I understand I am just a bit lost with this. I don't know this car or the parts you are installing but usually the line out from the trans goes to the bottom and the return out at the top, the do this to prevent air being trapped. in the cooler that is in the radiator tank if its mounted vertically.
When the fluid to air cooler is added into the system there is no return from the radiator it is in series.

Leaving the thermostat out of the equation for now the line out from the trans goes into the lower radiator fitting, the out line from the radiator goes to the inlet side of the other cooler and the out side is the return to the transmission.
Everything is the same with the thermostat installed it just loops the most of fluid back to the trans without ever getting into the coolers until a set temp is reached. The thermostat block the out flow from the trans to the cooler and the return from the cooler that is why I question the dry return line.

It may well be fine, I dont know as I am not familiar with it and heve no info.
 

Rochev

Thread starter
Messages
96
Location
Maine
I appreciate your input! So basically there's no hose going to the lower end of the radiator, they both go in/out the top. In the picture, it's #5.(Disregard #1, diagram is for an older model. The t-stat is in #5 in mine.) You can see the nipples (only word I thought would work) sticking out the top side of the radiator. Long story short, the trans-out line remains in the radiator, radiator-out line goes to the new aux- and the aux-out line is routed into the trans-in. Why there's never close to a full amount of fluid in the trans return/suction line I have no idea but it is worrying me. Again, she's driving just the same...I would think it would be noticeable if there's no fluid circulating, if not at least a vivid warning like any other it displays.
 

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Rochev

Thread starter
Messages
96
Location
Maine
Just an update, I caught it at the right time. Even after shutting it off there was a lot of fluid in the return line. However using vinyl wasn't the best idea as it won't stop kinking and flattening itself at every bend. Will have to get OEM hoses from a wrecked police car.
 
Messages
25,433
Location
MA, Mittelfranken.de
Vinyl is the worst possible hose for this application, if it is just hose with no fittings you can buy transmission rated hose at Napa by the foot.
If it is 3/8 hose get Honda spring clamps from any Honda dealer or online. Honda Part# 90635RV0003, they are the best I can ever remember using, seriously heavy duty spring clamps.
 

Rochev

Thread starter
Messages
96
Location
Maine
Just to update. The OEM cooler I installed is for the Police package cars. They have NO connection to the radiator, it's a standalone aux cooler for the transmission. That's why I had such a hard time trying to figure out how to route it. I'll have to add some lines and couplers. Vinyl was indeed the worst material I could have used. Too difficult to maneuver without it bending, especially when cold. I'm going to pick up rubber fuel/oil lines but I need to figure out the diameter. I believe it's 5/8.
 
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