VW Passat TDI and Towing

[AusFletch]

I have a VW Passat TDI that I'd like to use to tow a light (total weight <1,500 pounds) motorcycle trailer. Destinations would include the Rockies.

The owner's manual says the vehicle is not rated for towing. My VW mechanic says to go for it (go figure...guess who would be fixing it? ). Actually, he is a good friend and I trust him but find it hard to ignore the manufacturer's advice.

Typical internet searches have not helped much. Does anyone here have any advice or experience (in this particular topic)???

-FLETCH

[TypeSH]

Have you checked a TDI forum? Surely others have towed with the vehicle and could give you feedback. Are there hitches made for the car? I would say most likely that towing with it would be fine, especially since it is a diesel and drivetrain is probably very strong.

[DANNYROTH]

John Bennett took some pictures of a TDI rigged up for towing and showed them here:
http://z1.invisionfree.com/forums/ET...showtopic=6342

I don't know who owns the vehicle, but it apparently impressed John.

[euromedic]

http://forums.vwvortex.com/zerothread?id=2597294

[sharkey]

I would think you'd be ok. I mean, it has gobs of torque. You might put a tranny cooler on it if it is an auto.

I wanted the new Jetta TDI Wagen and planned to hook up a pop up camper to it.

[Tracker]

I had a TDI. My concern would be the tranny more than the engine. Is it auto or manual?

[John Bennett]

Like Danny said, I saw this guy in Groveton Saturday. He said he was headed to Ohio to pick up a Yamaha Venture and haul it back. He said got this hitch from J.C. Whitney and regularly tows his big Harley Electra-thing.

The guys on TDIclub.com say they tow all the time, even though the manual says don't.





My father has one of these Top Hat trailers. They are pretty heavy.

[prhaussies]

I have pulled trailers with my 50+ HP 66 Bug and my 79 Honda Accord. We went all the way to Ouray, Co. without a problem. I think any modern vehicle with the right hitch will be ok for any light duty towing. RH

[94GTVert]

Originally Posted by AusFletch

I have a VW Passat TDI that I'd like to use to tow a light (total weight <1,500 pounds) motorcycle trailer. Destinations would include the Rockies.

The owner's manual says the vehicle is not rated for towing. My VW mechanic says to go for it (go figure...guess who would be fixing it? ). Actually, he is a good friend and I trust him but find it hard to ignore the manufacturer's advice.

Typical internet searches have not helped much. Does anyone here have any advice or experience (in this particular topic)???

-FLETCH

My advice is to buy a real diesel and get a Powerstroke or Cummins and tow some real trailers more like 15,000lbs lol

[whoa]

Originally Posted by AusFletch

My VW mechanic says to go for it (go figure...guess who would be fixing it? ).

If its Roger at Motormania, he knows more about what the car can handle than VW.

I'd forget the trailer and just drive the car and run it on the track! Fun car.

[KenH]

Passat TDI? 2.0 turbodiesel? I'm guessing 3500 pounds empty. Add 1500 pounds of trailer. Gross weight of the rig, less weight actually carried in the vehicle, will be 5000 pounds. add in people, fuel and other fluids, liggage, tools, and a picnic basket, and I expect your rig will be knocking on 6000 pounds all together.

I was born in a travel trailer and still live in an RV. I could find no information on towing with my van, so I went through this entire process to determine if and what i could tow. Here's more than you ever wanted to know about setting up for towing:

Issue #1: Driveline durability.

6000 pounds is a lot of mass for any 2.0 to push around, so internal engine component loading may be a factor. The engine may make plenty of power to pull the rig, the question is for how long will it be able to do so without over-stressing the engine. In normal situations, high throttle settings are a momentary occurance. When towing in the mountains, it is common to hold the petal near or on the floor for several or many consecutive minutes if you want to make speed.

A marine engine will be rated at various horsepower levels depending on throttle settings. An engine rated for 300hp in a car may only be rated for 250hp in a competition ski boat that only sees a minute or two of high throttle at a time and 150hp in a cruising boat that may run at high throttle settings for hours at a time.

To protect your engine and driveline, do not operate at high throttle settings for a long time. Slow down and manually downshift if necessary to avoid long periods of high throttle settings or lugging the engine. At times coming back from Big Bend, the Roach Coach was slowed to 35mph in 2nd gear at half throttle by headwinds and hills. Patience is the reason the little 2.5 is still running strong at 201,000+ miles.

Issue #2: Vehicle payload capacity and trailer gross vehicle weight (GVW).

It is necessary to consider vehicle payload capacity to determine maximum trailer GVW. If your car weighs 3500 pounds empty, and has a GVWR rating of 4500 pounds, then its payload capacity is 1000 pounds, as long as the payload is properly distributed so that neither axle weight rating is exceeded. You can usually find axle weight ratings and GVW ratings on a placquard affixed to the driver's door or in the owner manual. Note that the GVW rating is not the sum of the axle weight ratings, but somewhat less.

Next, add up the weights of fuel, oil, coolant, brake fluid, battery acid, washer fluid (empty vehicle weights are usually dry, figure 8 pounds per gallon of diesel and fluids), people, tools, luggage, and everything else you plan to have in the car during the trip. Subtract the sum from the vehicle's GVWR listed on the placquard. Now deduct the weight of towing equipment (hitch, wiring, electric brake controller, etc.) that will be bolted to the car. This difference is your excess payload capacity.

Rule of thumb: Exchange 1 pound of excess vehicle payload capacity for 10 pounds of trailer GVW. At a ratio of 1 pound payload to 10 pounds trailer GVW, you'll need 150 pounds of excess vehicle payload capacity to tow a 1500 pound trailer.

Now, consider what will happen to load distribution and its affect on axle weights when 150 pounds (minimum hitch load for a 1500 pound trailer) plus the weight of the towing equipment is dropped on the back bumper of your car, loaded and fluids topped for the trip, including passengers. Are the axle weights still within limits? Can you redistribute the load so the axle weights are acceptable? If not, don't plan on making the trip in the Passat.

Issue #2: Cooling. Low air densities at high altitudes do not cool as well as high air densities at lower altitudes. Starting up with a trailer is akin to starting up going up a hill every time. Highway towing is similar to driving uphill all the time. There are several issues to be aware of. Not all will apply to every towing situation. I highly recommend real temp gauges for coolant, engine oil, and transmission fluid if equipped with an automatic. These three guages tell you everything you need to know about threats to your driveline's health when towing. An exhaust gas temp gauge can save an engine with otherwise healthy fluid temperature parameters. The turbo bearings you save from cooked oil may be your own.

Pay particular attention to transmission cooling if you have an automatic trans. Run the trans fluid through a remote cooler, then back through the cooler in the radiator if so equipped. This routing will allow excess cooling capacity in the trans cooler to assist the radiator while preventing over-cooling the trans fluid, which leads to acid buildup in the fluid and ultimately trans failure. You can also run a mechanical thermostat to prevent overcooling the trans, and this is required if there is no cooler in the radiator.

With a manual trans, the clutch will take a beating from standing starts, especially uphill with a load. Keep clutch temps under control by swapping final drive gearsets to a higher numerical ratio.

Engine coolant temp is also critical. Diesels generally run cooler than gas engines, so often a diesel radiator is of lower capacity than the gas-engined brethren of the same model. Sometimes a radiator for a gas engine can solve a multitude of cooling problems for a diesel.

Engine oil temp affects engine longevity. 180*F is ideal. Any lower, and the potential for acid and varnish build-ups in short-trip driving are problems. Any higher and the oil loses its lubricating properties faster. An engine oil cooler can remove significant heat from an engine, taking some load off the radiator. Be sure to include a thermostat to prevent overcooling. Cool oil is vital to the life of turbo shaft bearings.

Added oil capacity is always a benefit for any engine. A good way to increase capacity and insure clean oil for turbo bearings is a dual remote oil filter base that takes a pair of quart spin-on filters.

Fans are most efficient when fully shrouded. If the entire radiator core is not covered by the fan shroud, the fan can't pull air through the entire core, wasting cooling capacity.

Fans are generally not needed at highway speeds because the motion of the vehicle through the air forces enough air through the radiator to keep the coolant temps down. Unfortunately, fan shrouds interfere with this forced air cooling at highway speeds. I've used a speed-sensitive switch to open and close doors in shrouds automatically, and an ordinary generic clutch cable to do the same manually. Chevrolet used spring-loaded doors in some Corvettes because the engine-driven fans so impeded the ram effect at high speeds.

If anything starts to heat up while towing, turn off the air conditioner. Most cars have the condensor placed in front of the radiator. The condensor heats the air before it goes through the radiator. Turning off the AC allows cooler air to reach the radiator. Keep in mind that the defrost setting also runs the air conditioner, so don't use defrost if engine temps rise.

Issue #3: Brakes.

Mountains. Electric trailer brakes very highly recommended. It is possible to make it through the mountains without trailer brakes, and it's also possible to not blow your brains out playing Russian Roulette. Trailer brakes should be set not to lock up in a panic stop. If the trailer brakes lock up and the tow vehicle brakes do not, the trailer will likely try to pass the tow vehicle. Not good.

Towing Tip: Sway induced by crosswinds or passing trucks is easily stopped by slightly dragging the trailer brakes for a second or two.

Issue #4: Electrical system.

Does the tow vehicle have sufficient electrical generation and storage to supply trailer lights and brakes at engine idle speeds in stop and go traffic? Adding trailer lights may drive the turn signal flasher crazy. Solve hyper flash rates with a heavy duty or electronic (non-load sensitive) flasher unit. Does your Passat have separate brake and turn bulbs? If so, you'll need to either add additional trailer lights or wire in an adapter to convert the Passat rear lighting configuration to the trailer lighting configuration. Adapters are about $12 at Walmart. Be sure to hook a gorund to both the tow vehicle and trailer chassis. Trailer hitches and safety chains don't make good grounds.

Here's how the numbers worked out with the Roach Coach:

GVWR = 4080 pounds
- Empty weight 2800 pounds
= payload capacity 1280 pounds

- 20 gallons gas @ 6.2 pounds each = 124 pounds
- 1.25 gallons oil @ 8 pounds each = 10 pounds
- 1.5 gallons coolant @ 8 pounds each =12 pounds
- 1 gallon washer fluid @ 8 pounds each = 8 pounds
- .25 gallon brake fluid @ 8 pounds each = 2 pounds
- 52 pounds towing equipment = 52 pounds
- 650 pounds people and luggage = 650 pounds
= excess payload capacity of 422 pounds.

422 x 10 = 4220 pounds theoretical trailer GVW without overloading the suspension or tires, and axle weight ratings of 2800 pounds each easily in limits.

Now, my bike weighs 274 pounds wet, and may trailer weighs 140 pounds total, so I could throw the bike in the back of the van, toss the trailer on top, and still not overload the driveline, engine, brakes, steering, or suspension. However, I also had to plan for a second bike at 550 pounds. The GVW of the loaded trailer was still under 1000 pounds, with a 100 pound hitch load, so I am still good to go suspension and tire wise.Adding 800+ pounds of passenger, bike, and luggage was definately noticable with throttle response and braking. Trailer brakes would have provided peace of mind with two bikes, not a problem with just T-dub back there. I used 2nd gear coming down past the observatory to ease the load on the brakes.

I don't plan to add trailer brakes because my street bike is 475 pounds wet, and without a passenger and that luggage, my trailer with both bikes will be under 900 pounds and my excess carrying capacity will be increased by 300 pounds.

I've replaced the OEM single core radiator with a dual core radiator and added a transmission cooler. Since the Roach Coach is a base model with no electrical options, the standard alternator and battery have plenty of capacity for the added trailer lights.

[euromedic]

It took some research, but based on the new Passat TDI that is available in Europe i have found the following. This is from the dutch Volkswagen website:

Trailer w/o brakes capacity , kg 740 = 1628 pounds
Trailer with brakes capacity, kg 1500 = 3300 pounds
Hitch weight capacity, kg 85 = 187 pounds

When you travel to Europe during the summer vacation season, you will see countless compact cars, sedans, and wagons; pulling travel trailers of all shapes and sizes. Count in all the weight of luggage/people/recreational items, and you will see that you car is more than able to pull a motorcycle trailer over a long distance. This is the rig i had when I picked up the motorcycle from the airport:



Volkswagen Golf with 110 hp 4 cylinder, pulling approx. 1000 pounds of trailer/motorcycle/crate.

[AusFletch]

Wow. That is tons of helpful information. Thanks to everyone. I think I know what I am going to do now. -FLETCH

[flb_78]

The engine will handle it with no problems. It would be the transmission that I would be concerned with.

[AusFletch]

Originally Posted by KenH

Here's more than you ever wanted to know about setting up for towing:

Ask for the time, learn to build a watch? Just teasing. That is TONS of useful information. Thanks for taking the time to share it. You have given me a great deal to consider. And re-consider. -FLETCH

[KenH]

I worked for a Horizon trailer in south Florida. Mostly boat and utility trailers, but they also did custom toy haulers with RV acommodations. Most of our customers were boat dealers and knew little or nothing about setting up tow vehicles.

My job was to assist dealers with planning tow vehicle preps to insure safe and trouble free towing. I also did a lot of problem solving. For instance, a man towed a 24-foot, 6200 pound boat/trailer with a Cadillac Eldorado. With 650 pounds of tongue weight, air bags were installed to level the car. Problem was, Eldorados are front wheel drive and the tires spun too easily going up hill on a wet ramp. One steep ramp the car/trailer combo had to be towed up by a 4x4 pickup. The solution was two parts: first, ditch the air bags and add an equalizer hitch to transfer tongue weight to the front wheels. Now the car sat level, just a little lower than without the trailer, and more weight was on the front axle, which provided more traction. On that one steep ramp, the guy could use his electric tongue jack to raise the tongue and lift the back of the car, snap the equalizers up as tight as possible, then lower the weight back onto the hitch. This added a few hundred more pounds to the front axle. Second part of the fix was to swap the P235/75R15 tires for a set of P255/70R15 tires, which added an inch of tread width and more traction. No more problems.

[FatalException0E]

One of the best tow vehicles I've known for hauling a pair of small dual sports to Big Bend and back was my dad's '93 Taurus SHO. That car didn't even really have a lot of torque. When they started putting auto transmissions on the SHO, they had to add a little displacement to the engine to get enough torque to run the slushbox.

The low-ish gearing and stick shift is what made that car so great. If the car has a tachometer, how many RPMs does it turn when cruising ~70?