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Re: Sienna Gen-II Towing Capacity.

I read this whole thread and feel a little ill now. I have a 2009 LE and was told multiple times by the dealer that I could tow up to 3500lbs. This is our third Toyota from this dealer and we are fairly good friends with our salesman. We do not tow much, but we do have access to a nice pop-up camper (in-laws) that we wanted to start using more now that our two boys are getting a little older. I was getting ready to order some parts for my Sienna so we could start towing the camper soon and came here to read up on some things first. I am glad I did!

As you can guess by now, I do not have the oil cooler on my Sienna. I had planned on getting a Class 3 hitch (Curt), Prodigy controller and a Reese WDS setup for the camper. My in-laws have a very similar setup on their Odyssey and love it. They used to tow without the WDS and he said that was the biggest single improvement he ever did for towing. He also hauls an enclosed, decent sized tool trailer with it and they camp several times a year driving all over the E Coast so I am trusting of his opinion even if on a different vehicle.

If I setup by LE with that equipment, can I tow the PUP? Most camping would be along the coast, so no mountains. May head to Disney with it, that is all flat driving. Not sure of the weight on the PUP, but it is a newer Rockwood w/ dual king beds, slide out dinette, & AC on a single axle. I have no issues switching out to syn oil or anything else that would be easy to do.

We also have a 2006 Highlander V6 With the factory towing package, but we prefer the Sienna for trips so would like to set it up for towing vs. the Highlander.

Thanks-
 

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Re: Sienna Gen-II Towing Capacity.

frvrngn said:
If I setup by LE with that equipment, can I tow the PUP?
The difference between with and without the towing preparation package (which is an oil cooler for Siennas with the 2GR-FE engine) is all about engine reliability, not safety. You can tow at least up to the 3500 lb limit regardless of the package; I think that the question is whether or not the effect on the engine is acceptable.

frvrngn said:
Not sure of the weight on the PUP, but it is a newer Rockwood w/ dual king beds, slide out dinette, & AC on a single axle.
The only current Rockwood model that I see with a dinette slide-out and dual "King" (almost King - 70"x80") beds is the HW316TH... and that monster is too heavy for even the 3500 lb rating, even when empty and bone dry! I hope that it is a different model, but the point is that it will be far beyond 1200 lb... even the very lightest current Rockwood pop-up is 1471 lb, again empty and dry.
 

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Re: Sienna Gen-II Towing Capacity.

frvrngn said:
Not sure of the weight on the PUP, but it is a newer Rockwood w/ dual king beds, slide out dinette, & AC on a single axle. I have no issues switching out to syn oil or anything else that would be easy to do.

i tow a flagstaff 625d with my 05 ce, as it is a canadian model it has the "tow-prep", at a listed 2500lb, it is an easy tow on my setup. i'm not sure that i would tow it on a non "tow-prep" model
http://www.forestriverinc.com/nd/default22.asp?location=rv&unittype=&page=floorviewertc&model=625D&choice=ftc&nav=rec&name=72&series=classic

the flagstaff has a sister model, 2318g, http://www.forestriverinc.com/nd/default22.asp?location=rv&unittype=&page=floorviewertc&model=2318G&choice=rktc&nav=rec&name=110&series=Freedom that is the same item, just the fabric colors have changed.


My setup has a p3 brake controller, a wd-350 weight distribution and air-lifts.


Paul
 

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Re: Sienna Gen-II Towing Capacity.

pgartner said:
frvrngn said:
Not sure of the weight on the PUP, but it is a newer Rockwood w/ dual king beds, slide out dinette, & AC on a single axle.

i tow a flagstaff 625d with my 05 ce, as it is a canadian model it has the "tow-prep", at a listed 2500lb, it is an easy tow on my setup. i'm not sure that i would tow it on a non "tow-prep" model
http://www.forestriverinc.com/nd/default22.asp?location=rv&unittype=&page=floorviewertc&model=625D&choice=ftc&nav=rec&name=72&series=classic

the flagstaff has a sister model, 2318g, http://www.forestriverinc.com/nd/default22.asp?location=rv&unittype=&page=floorviewertc&model=2318G&choice=rktc&nav=rec&name=110&series=Freedom that is the same item, just the fabric colors have changed.
Those linked models have one Queen bed and one almost-King bed; this is important only because I'm trying to understand how heavy frvrngn's trailer might be, and the beds and dinette are the features to identify the model. The two-King-bed models are half a ton heavier than the Queen+King models, and that's a critical difference for the capacity question.
 

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Re: Sienna Gen-II Towing Capacity.

I will need to contact my in-laws to find out the weight and/or model it is. We only used it once over a year ago. I know one side is definitely a king bed, since they bring their two 65lb Boxers with them and they like to sleep in the bed with them! I thought the other side was a king as well, but I may be mistaken.

What I do know is they tow it through the mountains of Virginia, W Virginia and New England with their Odyssey. They said it is not easy at times, but at the same time they are not crawling up the grades either. Having said that, I kind of doubt that it is a dual king model if they weigh that much.

I think at most we would use the camper twice a year. One site is close, only about 90 miles and some mild grades. Second most common site we would visit is about 200 miles and flat driving. Longest trip would be 500 miles and flat.

We did plan on keeping the Sienna long term. Our Highlander is paid off and the van is halfway there. Not sure if two trips a year towing will cause enough wear and tear on the engine to make a difference in the long term or not. That is why I came here to do some research before I invest in all the gear necessary to equip my van for towing. If things went well on our first couple of trips we were going to then go ahead and get our own PUP.
 

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Re: Sienna Gen-II Towing Capacity.

engine and engine cooling are not the issues. suspension capacity and transmission are the serious weak links. suspension is obvious because everyone is running air lifts. remember 3500 lbs is with nothing and no one in the van. as you add passengers you have to derate the trailer. i have towed 3000lbs for about 40K miles. the engine will do fine on flat roads and in mountain climbs the computer will simply detune the engine to avoid heat build up. so you just climb slowly. but the wheel bearings, shocks and transmission just cannot take it. heat and mountain climbs just destroy these parts. like a climb out of Phoenix and up to Flagstaff in August. 115 degree outside temps. the computer shutsdown AC to conserve power and manage heat. not fun with a an full of kids. in the end we learned it's not a vehicle designed for towing
 

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Re: Sienna Gen-II Towing Capacity.

so much wrong here. From my other reply:

Tire remnants in the desert are due to heat from the surface (sand, asphalt, etc) not air moving inside a tire.

Scrubbing is caused by a tire not rotating exactly perpendicular to the road and on camber. The sienna's rear beam holds things as parallel as possible, even under load. If you read the original poster's message(OP) he already uses airbags and WDH, meaning the rear sag on his Sienna isn't great.

Sidewall flex causes heat, but if you actually read the OP message, you'll see his WHEELS were hot and the tires were NOT. That indicates a brake issue vs. tire.

Tongue weight should be 10-15% of trailer weight for stability.

The 3500lbs trailer weight rating leaves about 1100lbs for tongue weight, cargo and passengers inside the Sienna if you actually checked the GCVW, GVWR and hitch capacities. The Sienna's tongue is actually rated for up to 525lbs with the correct WDH system. That's actually in the manual.

Towing a heavy trailer in 115 heat will cause problems in pretty much any tow vehicle running at its weight rating. Do your travelling during cooler daytime hours.

The weight ratings and other things are fully discussed in the towing section of these forums, please read them.

minivan said:
engine and engine cooling are not the issues. suspension capacity and transmission are the serious weak links. suspension is obvious because everyone is running air lifts. remember 3500 lbs is with nothing and no one in the van. as you add passengers you have to derate the trailer. i have towed 3000lbs for about 40K miles. the engine will do fine on flat roads and in mountain climbs the computer will simply detune the engine to avoid heat build up. so you just climb slowly. but the wheel bearings, shocks and transmission just cannot take it. heat and mountain climbs just destroy these parts. like a climb out of Phoenix and up to Flagstaff in August. 115 degree outside temps. the computer shutsdown AC to conserve power and manage heat. not fun with a an full of kids. in the end we learned it's not a vehicle designed for towing
 

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Re: Sienna Gen-II Towing Capacity.

just trying to help... tires are in fact air pumps. wheels feel hot because they are aluminum. aluminum is a conductor and ribber is an insulator. you feel heat on the rims due to efficiency in transferring and dissipating heat. with regards to scrub; this one is easy. jack your car up and watch the camber/caster shift. then do the same while compressing the rear suspension. this is exactly what happens (not to the same degree) while travelling down a road. If he is experiencing it on the front tires it may likely be wheel slip. FWD is terrible for towing heavy. weight shifts to the back (especially up hill) and traction losses occur. accelerate somewhat aggressively in rain with Traction control off and you will experience it. WDH helps slightly but it is a relatively slow system which does not respond well to dynamic loads (bumps). August is a great time to travel. Kids are out of school and the country is beautiful. can't see much in the dark. 115 degrees, uphill, in thin air is fine.... in the right vehicle correctly loaded.
 

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Re: Sienna Gen-II Towing Capacity.

Perhaps it would be a good idea to keep the discussion of the Wheels hot after towing? issue in that topic, and not confuse this one.

minivan said:
engine and engine cooling are not the issues.
Engine oil cooling is a limiting factor in Siennas with the 2GR-FE engine, as is quite clear from the towing preparation package contents and corresponding ratings. Engine oil cooling may be a factor for Siennas with the 3MZ-FE engine, as it may be a limitation on GCWR, but only at the level of the package-equipped vehicles. The ability of the engine cooling system to dissipate heat may also be a factor in the GCWR, which in turn limits the combination of trailer and cargo which can be towed (but is not the source of the 3500 lb trailer limit in the absence of load carried in the van).

minivan said:
suspension capacity and transmission are the serious weak links.
Suspension capacity is always a potentially limiting factor for any towing vehicle. Rear suspension load rating (GAWR) is a limitation for weight-carrying towing only if also carrying a significant cargo load; without cargo, a tongue weight far beyond the vehicle's rating (which may be due to structure) and corresponding to an enormous trailer could be accommodated by the rear suspension.

The current Highlander - with the same engine as the current Sienna and presumably the same transmission - has a higher towing rating; I suspect that this is related to the taller and thus higher-capacity tires which come with the "SUV" style, as the stock Sienna tires limit the GAWR.

The transmission may indeed be a limiting factor to GCWR, and thus to trailer towing but only when also carrying significant passenger and cargo load.

minivan said:
suspension is obvious because everyone is running air lifts.
I agree that it is obvious from the effective and popular use of air bags in the springs that towing is better with more rear suspension stiffness, and with rear suspension adjustability. This doesn't change the towing rating, which is the subject of this discussion.

minivan said:
remember 3500 lbs is with nothing and no one in the van. as you add passengers you have to derate the trailer.
As already mentioned, this is incorrect, although it is a somewhat common misconception as people apply a general rule of thumb where it is not appropriate. With the full 3500 lb of trailer, there is still room to the GCWR. The Sienna's trailer rating is not determined as the difference between the curb weight (with driver allowance) and GCWR, as is common for light trucks; if done on that basis, it would be considerably higher.

minivan said:
i have towed 3000lbs for about 40K miles. the engine will do fine on flat roads and in mountain climbs the computer will simply detune the engine to avoid heat build up. so you just climb slowly.
I have not noticed this effect. I can understand how the engine running hot could increase the tendency to preignition (pinging) and cause the engine to adjust (presumably by retarded timing) to compensate, which would reduce power. I would be surprised if engine power were limited in response to engine temperature, but it is possible to do.

minivan said:
but the wheel bearings, shocks and transmission just cannot take it. heat and mountain climbs just destroy these parts. like a climb out of Phoenix and up to Flagstaff in August. 115 degree outside temps. the computer shutsdown AC to conserve power and manage heat. not fun with a an full of kids.
I find it hard to imagine that the bearings of a modern vehicle operated within GAWRs on a highway would have any problems. SiennaChat members who have been towing for several years are not reporting bearing failures, as far as I know.

Many years ago cars were equipped with switches which disengaged the air conditioning compressor at wide-open-throttle to leave full power for acceleration during those brief periods. I can only speculate that keeping the accelerator to the floor may still have the same effect, which could be annoying if full throttle is used for sustained periods. I have towed up long mountain grades with the pedal to the floor, but do not recall if A/C was interrupted.

minivan said:
in the end we learned it's not a vehicle designed for towing
I agree. The only vehicles designed specifically for towing are tractors; even a "one-ton" pickup truck is far from ideal for towing. In the continuum of design priorities for a road vehicle from a single-seat race car to a highway tractor, the Sienna is toward the passenger end, but still far more multi-purpose than a typical sedan. I think it makes a very capable tug within its rated range.
 

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Re: Sienna Gen-II Towing Capacity.

I am one of poor souls w/o the oil cooler, but am trying to see if it would be realistic to source the parts and install them.

Apologize in advance for double posting, but here's the EPC diagram that I've got from a good friend of mine who works at Toyota.

Would any of you be able to identify exactly which ones of these parts (and how many of them ) will be needed for retrofitting the oil cooler?

Thanks a bunch!!

Mot
 

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Re: Sienna Gen-II Towing Capacity.

We just returned from another 2 weeks of camping through the Canadian Rockies with the Sienna and our F-18Bantam. 3600lb trailer and a loaded up Sienna did fine through all the roads and mountain passes. Calgary-Edmonton-Jasper-Kamloops-Kelowna-Revelstoke-Golden-Radium-Banff and back to Calgary. 2800kms covered and the sienna was a champ. blew past a bunch of RVs struggling up Sinclair pass out of Radium at 80km/hr without issue. Roger's pass, not even a concern.

I logged speed, engine rpm, water temperature, throttle position and engine load throughout the trip on my OBD logger. never broke 4000rpm. water temps stayed at 180-195F throughout except for a slow windy section up to Kicking Horse Resort in golden where we got to about 205F. throttle position at <70% throughout and engine load never broke 80%.

I just swapped out 5liters of transmission fluid tonight and the old stuff looks a tiny bit darker than the new, but smells and feels exactly the same. Great tow vehicle.
 

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Just to add my 2 cents, one could add an oil filter heatsink with thermal paste which may be almost as effective as the oil cooler in the tow package. Google "oil filter heatsink"
 

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briank said:
... one could add an oil filter heatsink with thermal paste which may be almost as effective as the oil cooler in the tow package...
I understand the idea, and I suppose it couldn't hurt, but it would take a lot to convince me that some fins on the filter housing would have any substantial effect, let alone approach the effectiveness of the factory oil-to-coolant heat exchanger.
 

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Can anyone offer thoughts as to what gear(s) they typically use when towing? We just got a new(used) pop-up for our family and it has an unloaded weight of ~2400lbs.

Being new to towing with my 2006 Sienna, I do not want to neglect or abuse the automatic transmission, but want to be a good steward by finding out what it best on how to use it properly from experienced folks.

Also, can someone expand on the necessity of a Weight Distribution? It seems that most people here have them, but do we know why? Why is it good for the Sienna?

Thanks in advance for your thoughts.
 

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cmarks said:
Can anyone offer thoughts as to what gear(s) they typically use when towing? We just got a new(used) pop-up for our family and it has an unloaded weight of ~2400lbs.
I generally leave it in Drive.

The Sienna has no special "tow/haul" mode, so the shifting may not be quite as desired in some loaded conditions, so it may be prudent to manually take some action:
  • If the transmission "hunts" - shifting often between two gears as if uncertain which one is appropriate - this can be stopped by manually selecting the lower of the two gears. I have rarely noticed this, but it can happen while climbing steep extended grades, or even in more moderate condition if travelling right around the appropriate speed to change gears.
  • The Sienna's "grade logic" downshifts for engine braking on descents, but occasionally it may not downshift enough for the conditions (to avoid riding the brake to keep speed down as desired), so it makes sense to downshift to a low enough gear. I have only found this on very steep and slow grades.
  • The only perhaps "abusive" condition would be running with the torque converter not locked, instead of one gear lower and locked up. This would be a reason to shift down to the lower gear.

In practice, even while towing in Drive 5th gear is rarely used except on flat or gradually descending roads; it is an automatic and generally downshifts as appropriate.

This is a common topic, so I suggest looking for previous discussions in this forum before adding further to this topic, which is about capacity.
 

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cmarks said:
Also, can someone expand on the necessity of a Weight Distribution?
From the viewpoint of capacity, there are two considerations for use of a weight-distribution system.

The hitch weight limit in weight-carrying mode (no WD system) is 350 lb; any higher, and WD is required. This may be a structural limit, or perhaps set by Toyota to make it less likely that people exceed the other relevant limit...

... which is rear axle load. A WD system exists to remove load from the tug's rear axle, transferring it to the tug's front axle and to the trailer axle, in a proportion determined by relative inter-axle distances. The Sienna's Gross Axle Weight Rating or GAWR (for both front and rear) is 1290 kg (2838 lb), as shown in the manual and on the certification label at the driver's door. If hitching the trailer while carrying the passenger and cargo that are also along for the trip would exceed that limit, a WD system can reduce the load to an acceptable level... but so can shifting the load in the trailer and van in some cases.

Our travel trailer weighs about 2400 lb empty and we tow it at about 3000 lb loaded. The tongue weight is within the weight-carrying limit (about 305 lb typically) and with it hitched our rear axle load is no more than the GAWR. We do not use a WD system

Weight distribution system use is often discussed and can be controversial. For additional discussion, I suggest searching this forum for existing topics, and if appropriate starting a new one, rather than adding further to this topic... which is supposed to be about towing capacity.
 

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According to Toyota.com, the 2011 Sienna XLE (FWD) has the towing prep as "Standard". Would that be true of XLE models in 2008? Our 2008 Sienna XLE did not list the Towing Prep as an option on the window sticker from the factory; but the last time I had the van serviced at our Toyota dealer, they charged me to replace an "oiler cooler line".
 

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Got my answer from Toyota. So I don't have the towing package...but why is it that they charged me to change the oil cooler line? See response:
Subject

Towing Capacity for 2008 Sienna XLE



Discussion Thread

Response (ATia)
05/23/2011 12:49 PM

Dear Mr. Burns,

Thank you for contacting Toyota Motor Sales, U.S.A., Inc.

We appreciate the opportunity to address your inquiry.

We have researched your provided Vehicle Identification Number (VIN), 5TDZK22C88S117421, and can advise that this 2008 Toyota Sienna XLE is not equipped with the Towing Prep Package. You are correct that for the 2011 model year, the Sienna XLE receives the Towing Prep Option as standard equipment; however, the sales brochure for the 2008 Sienna, located at http://www.toyotacertified.com/ebrochures/08_sienna.pdf, lists the Towing Prep Package as optional for all 2008 Siennas. Referring to the specific list of factory options for the Sienna in question, it was not built with this factory option. As such, the maximum towing capacity for this vehicle will be 1,200 lbs. This recommendation is made in section 6-1 of the vehicle's owner's manual, titled "Specifications". We apologize for any confusion regarding the equipment level of your mother-in-law's vehicle.

If we can be of further assistance, please feel free to contact us at http://www.toyota.com/help/contactus.html.

Sincerely,

Alex Tiampo
Toyota Customer Experience
 

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jeburns55 said:
So I don't have the towing package...but why is it that they charged me to change the oil cooler line?
I don't know what happened in this case, but if it were my vehicle I would want a much more specific description. Automatic transmission fluid (ATF) is also casually (and correctly) called "oil", and there is a transmission fluid cooler. There's also a hose carrying engine oil for the VVT system which is not associated with a cooler, but is still and oil line and has needed replacement in many Siennas with the 2GR-FE engine (2007-current).
 

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I have a 2006 AWD limited, according to the brochure and some discussions here, I have the tow package as standard equipment. Based on the first pictures however my sienna doesn't look anything like what is shown. Do i for sure have the package? I got my hitch installed and just want to be safe.
 
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