Toyota Repair: Sienna cooling/towing, engine oil coolers, warm climates

Question
Thanks, Ted.
A lot of towing/trailer places online recommend adding transmission oil and/or engine oil coolers.  Do you think it would be a good idea to add one or the other (and which one)?  Would there be any harm from adding them?

Dick H.
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Followup To
Question -
Hi,
I have a 1998 Sienna.  It came without the towing package, and I'm wondering what the OEM towing package included (other than a hitch, of course).  I haven't gotten a straight answer out of 3 dealers or Toyota.  I want to tow up to 3500 lbs, the max rating for the vehicle with towing package.
1. What would I have to add/change to equal the OEM towing package?
2. (Semi-related question) Why are there two cooling fans on the radiator?

Thanks,
Dick H.
Answer -
Hello Dick, welcome to my expert page.
Looking through the factory repair manual I could not determine if there are any other options as far as the tow package is concerned so I'm going to assume that there are none, there are two cooling fans because one is the main fan and one is the auxillary fan(condenser fan) both will turn on when the air conditioning is used regardless of engine temperature. With the a/c off only the main fan is controlled by the temp sensor.

Answer
Yes it is probably a good idea to add some additional cooling device especially if you live in a or travel to warm climates or mountain driving, I'm not familiar with the different systems that are available, have you checked with the dealer to see if they have anything to offer?