[2004Owner]

will be doing some towing with my 2004 sienna next year, boat/trailer total weight is about 2200lb. I believe my van has the integrated tran cooler (it has two cooler hoses going between the rad. and the tran.) Thinking about renewing the rad as a preventive maintenance in the near future.

question, is it better to get a non-integrated one and add on an external tran cooler or just go with the same design?

 

[Roader]

I'd go with the latter. 2007+ Siennas with the 2GR engines seem to have occasional problems with a trans cooler pipe cracking outside the radiator, where it enters the radiator, but not so much your '04 with the 3MZ engine. Mine got a new Denso from Rock Auto a few years ago due to coolant seeping from the tank/body interface. No problems since. It's a sturdy, all aluminum design:

Maybe a bit sturdier than the the aluminum pipes-into-plastic-tank on the 2GR?

 

[wag3719]

The internal radiator transmission cooler serves two purposes, to cool the transmission fluid when it is hot and to warm it up when it is cold. Both are important.

 

[sixto]

All Siennas have the transmission fluid cooler in the radiator. I believe there is a towing package option with additional external transmission fluid cooler. You might look into that whether with Toyota parts or aftermarket.

Sixto
‘04 LE FWD 203K miles

 

[paul r]

I installed a transmission cooler a while back. I did it coz I could. Here is the discussion.

Installed a transmission cooler today

Its a B&M 70268 This is what it looks like. It came with some hardware and I modified the lower right bracket a bit. Note that I drilled through the plastic baffle with a 3/4 inch hole bit to pass the hoses through . For the top right bracket I used a dremel to make a slit for passing the...

www.siennachat.com

 

[DC_Dave]

We installed an external cooler in series with the radiator cooler. Transmission fluid temps were high when climbing - and stayed there for a while. If I was towing, I'd want an external cooler as well.

Easy transmission cooler install in Gen 2

New to me 2008 Limited AWD had fairly warm transmission fluid temperatures according to ScangaugeII, so we needed a cooler. Installed a Hayden 678 ($50 at amazon). To complete the install also needed 8" (hole-to-hole) of 3/4" strap iron, 2 small bolts & nuts, 4 washers, 2 zipties, and the kit...

www.siennachat.com

 

[Roader]

From my time on this forum, all North American Siennas have the towing package. I don't know this for a fact but I've yet to see a post with anyone buying a radiator w/o the towing package..

No NA Siennas came with external trans coolers in addition to the oil-to-water trans cooler built into the radiator, to my knowledge.

 

[sixto]

Back to my ‘72 Corolla, any Toyota automatic I’ve seen has a transmission fluid cooler in the radiator.

I replaced the radiator fans recently. There was an option for towing package which had a bigger driver side fan. I couldn’t find one for a reasonable price so I replaced my fan with a not specified for towing package fan that looks just like the original one. So what’s in the towing package besides a bigger driver side fan? Bigger radiator?

Sixto
‘04 LE FWD 203K miles

 

[Roader]

So what’s in the towing package besides a bigger driver side fan? Bigger radiator?

Sixto
‘04 LE FWD 203K miles

Yes. The dimensions are listed on RockAuto's website. The core thickness on the one without the towing package is 5/8" vs. 7/8" for the towing package model.

 

[2004Owner]

not sure if rockauto had a typo or what but just bought a denso rad w/ tow pkg for my 2004 for $47. (2nd in the list)

 

[Roader]

Sweet! I paid almost $100 for the same radiator over three years ago. Denso must be overstocked in the PRC.

 

[paul r]

Its back up in price. It is now $183.99

 

[2004Owner]

Its back up in price. It is now $183.99

 

[tonystewart]

Good day
Consider servicing the transmission as well.
220,000+ miles with original transmission, I service every 30K miles

 

[Craigrrr]

add an external tranny cooler and a magnefine filter

 

[tonystewart]

add an external tranny cooler and a magnefine filter

Great idea

 

[qgjrtys3851]

" 2007+ Siennas with the 2GR engines seem to have occasional problems with a trans cooler pipe cracking outside the radiator, where it enters the radiator, but not so much your '04 with the 3MZ engine."

According to Car Care Nut, he has seen many Sienna's lose the transmission for just this reason. And there is no warning when the pipe cracks and then all the fluid dumps and the transmission is ruined. He recommends not to take a chance and change out the radiator and cooler on older Sienna's (start at 15:57 in link below). I have a 2009 and will be doing this.

(290) 2004-2010 Toyota Sienna Buying Guide Part 1 : Engine and Transmission - YouTube

 

[mtdelvecchio]

will be doing some towing with my 2004 sienna next year, boat/trailer total weight is about 2200lb. I believe my van has the integrated tran cooler (it has two cooler hoses going between the rad. and the tran.) Thinking about renewing the rad as a preventive maintenance in the near future.

question, is it better to get a non-integrated one and add on an external tran cooler or just go with the same design?

I have a 2006 LE, 194,000. I tow a 2100lb pop up. I use a scan guage to monitor my trans temp. I did get a lot of high temps with hill climbs. I replaced my radiator about 2 years ago and while doing that I put an external trans cooler on. Quite easy with the radiator replacement. I run about 15 degrees cooler since putting on the cooler.

 

[msteel]

From my time on this forum, all North American Siennas have the towing package. I don't know this for a fact but I've yet to see a post with anyone buying a radiator w/o the towing package..

No NA Siennas came with external trans coolers in addition to the oil-to-water trans cooler built into the radiator, to my knowledge.

My 1999 Sienna LE has a transmission cooler in the left front fender. It looks factory to me, but I'm not the original owner. It is a California emissions model. It also started out as a fleet vehicle so I suppose if the original buyer put in a large enough order it could have been custom ordered with special options.

It looks to me like vehicles that have the transmission cooler in the fender will not have fog lights, because the fog light location appears to be about the only place air can enter to flow over the transmission cooler.

 

[MiniVan2001]

The Toyota external tow cooler is very well designed with a bypass if the ATF is too cold. It will flow to the extra cooler when the ATF is hot.