External Trans Cooler Size -How to know what size?

Hey Guys,

I have a 2008 Volvo XC90 3.2 6 cyl.

My factory trans cooler on the main radiator is leaking AT Fluid on the coolant so I will bypass it and install a external Trans Cooler on the front of the condenser

I'm not sure how many rows on the trans cooler I need. Can you guys advise me what size to get in order that my transmission is on the safe side? (AT Fluid not cooling enough or overcooling)

Here are some things to consider:

  1. I don't tow any trailer, neither do I do any of road driving or racing
  2. I use my car to drive normal in the city to go to work.
  3. I live in Central America, we have "all year" tropical climate temperature, almost 100% humidity and it also rains a lot.
  4. I don't want to buy a new main radiator. It cost more and importing is going to cost and replace it will also cost too.🤑

I was thinking in ordering a HAYDEN Trans Cooler 401

Economy Tube and Fin Style Cooler (Light Duty); Size - 5" x 12 1/2",

HAYDEN 401.jpg

But I don't know if is better to go with the HAYDEN 676.

Premium Plate and Fin Style Cooler (Light Duty); w/o Bypass; Size - 11" x 5 7/8"

HAYDEN 676.jpg

My Concern is that maybe I will be overcooling or not cooling enough.

What's your advice?

Thanks for your time and help

Isaac

 
Messages
5,406
Location
Fort Worth, Texas
The biggest/largest Staked Plate cooler that will physically fit........In your climate you don't have to worry about over cooling.

The Liquid to Liquid cooler in the radiator is very efficient, Air to Liquid are less efficient & have to be a lot larger.

Both the ones you listed look too small, Wouldn't even consider a Tube & Fin style.
 

JHZR2

Staff member
Messages
45,646
Location
New Jersey
I would guess that at minimum you would want to know AT pumping volume, pressure, and allowable delta P. Sure, you can in theory oversize the cooler and make the fluid “too cool”, but in practice aim not sure. I would suspect that you might need a thermostat-controlled unit, because coolant warms up faster than oil, and in some cases it may actually be a heater. You won’t have that situation here. But not sure if you can do that with an AT cooler, since fluid is always pumping... So I think further study may be necessary.
 

Isaac

Thread starter
The biggest/largest Staked Plate cooler that will physically fit........In your climate you don't have to worry about over cooling.

The Liquid to Liquid cooler in the radiator is very efficient, Air to Liquid are less efficient & have to be a lot larger.

Both the ones you listed look too small, Wouldn't even consider a Tube & Fin style.

Hi Clinebarger,

I was checking and HAYDEN recommends the size based on the Gross Vehicle Weight. May car weight 4,000

That's why I was thinking to get the size I mention before.

(Your cooler choice should be based upon the Total Vehicle Weight plus the weight of whatever you might be towing)

Part No. GVW SIZE
Width X Height
1401 12,000 12 ½” X 5”
1402 16,000 15 ½” X 5”
1403 18,000 12” X 7 ½”
1404 22,000 15 ½” X 7 ½”
1405 26,000 15 ½” X 10”


Thx & Rgds

Isaac
 
Messages
161
Location
Texas
I put a 18,800 tube and fin cooler in my 07 Mazda RX8. It took 14 degs F out of system, and will cool engine coolant too when cruising. I can drive 100 mph on a 100 deg f day and coolant and ATF will be 193 deg f. I took out the rock guard, and attached brackets there.
 

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Messages
2,272
Location
Seattle-ish, WA
The bigest/largest Staked Plate cooler that will physically fit........In your climate you don't have to worry about over cooling.

Yes. This again, and yes. Yes to what Clinebarger said.

I have installed coolers on many vehicles, this is the bottom line always.

And to be totally relevant, I have an 04 XC70 with the near same design/drivetrain. I now run a 676 downstream of my working factory cooler. I'm in a COLD climate and both together provide "adequate" cooling, but not too much. I had a 401 installed originally and upgraded it later.

FYI, if you need a 676, I have an extra (in box, new) I could sell cheap and ship as cheaply as possible. I do not mean to be drumming up business, but I see you are outside the US and I know sometimes getting things can be heinously costly. The XC70 could in fact take one larger than the 676, and imagine the XC90 should be able to take a larger one still. In Central America you need to fit the largest one you can and not worry about over-cooling at all. Like what Clinebarger said!
 
Messages
5,027
Location
Ohio
Why not just replace your 12 year old radiator and ditch the aux. cooler idea? It worked for 12 years and you would also benefit from the improved engine cooling of the new radiator. The replacement radiators for your vehicle are not that expensive.
 
Messages
2,272
Location
Seattle-ish, WA
Why not just replace your 12 year old radiator and ditch the aux. cooler idea? It worked for 12 years and you would also benefit from the improved engine cooling of the new radiator. The replacement radiators for your vehicle are not that expensive.

I appreciate your logical construct here, but it also presumes the OP is a fool and can't do the obvious math:

a) He's in Central America,
b) Have you even priced OE Volvo parts in NORTH AMERICA?

I know he's in Panama, and I don't know that at all, but I've spent decent time in Guatemala and Honduras. You can't order up RTV cheaply, much less an OE Volvo rad. Let's presume the OP isn't an idiot, maybe he knows what he's asking...

I point this out since I sometimes define certain mechanical/financial limits and inevitably someone says (effectively) - 'hey Geezs, for just a grand more you can fix it this way - so why are you so cheap?"

Let's try to maybe not do that?
 
Messages
5,027
Location
Ohio
I appreciate your logical construct here, but it also presumes the OP is a fool and can't do the obvious math:

a) He's in Central America,
b) Have you even priced OE Volvo parts in NORTH AMERICA?

I know he's in Panama, and I don't know that at all, but I've spent decent time in Guatemala and Honduras. You can't order up RTV cheaply, much less an OE Volvo rad. Let's presume the OP isn't an idiot, maybe he knows what he's asking...

I point this out since I sometimes define certain mechanical/financial limits and inevitably someone says (effectively) - 'hey Geezs, for just a grand more you can fix it this way - so why are you so cheap?"

Let's try to maybe not do that?
No, I don't assume he is a fool and who says you have to put an OEM radiator on it? I wouldn't. Someone in the aftermarket makes that radiator for Volvo, I doubt Volvo does. I think you are assuming too much. Let him decide with the suggestions being offered. I offered a possible solution, you offered criticism which won't help anyone.
 
Last edited:

Isaac

Thread starter
Hey Guys Chill Out 🤣

Here in my country with the Covid 19, quarantine….. Business are very slow and things are difficult and now its look like we will have to quarantine again because the cases of sick people have risen again….

I really dont know was going to happen on 2021 so I was trying to save some money.

After checking for the bigger Trans Cooler I can fit and the cost of it, I decided to bite the bullet an go with a aftermarket TYC brand Radiator.

I have to bring it to my country so I have to pay S/H + Import Duties🤬 And its look like installing the radiator is a PITA!

What can I say? This car is a money pit 🤑

Just a few weeks ago, I replace the starter motor and now this!

Guys, thanks a lot for your time and help

Rgds

Isaac
 
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