People ask me all the time about our experience with the Mercedes GL320 as a tow vehicle.  I think half the people who ask truly want to know if they should consider it for themselves, and the other half are hoping I’ll admit that I really can’t tow my Airstream with anything less than a 3/4 ton truck.  I probably disappoint a lot of people, because I tell the first group the brutal truth about the cost of Mercedes parts and service, and I tell the other half that it has done just fine towing “that big Airstream” for over six years.

It’s time for an update.  The Mercedes now has 107,000 miles.  Probably 80% of those miles were traveled with our 30-foot Airstream Safari in tow, so we’ve certainly worked the Merc as much as we can.

When I bought this car back in 2009 I said it had better give me 250,000 miles of service or I’ve made a big mistake.  To date, I’m encouraged. It hasn’t been amazingly more or less reliable than our previous Nissan Armada, but overall it hasn’t been terrible. There were far too many instances of “Check Engine” lights a few years ago, but all the bugs seem to have been worked out and lately our visits to the dealer have been either routine maintenance or other repairs that are associated with high mileage or age.

The warranty is long gone now, as is the extended warranty.  I pay for all the repairs, so I’m watching the expenses carefully. Here’s what it has consumed (other than routine maintenance like tires and battery) since 2013:

June 2014: Blower motor (for climate control fan) wouldn’t shut off. It was corroded and had shorted out. Replaced at a cost of $539.  Mercedes parts ain’t cheap.

July 2014: The air conditioner had been intermittently failing for years.  It finally got bad enough to replace the compressor, at a cost of $1,289.  Ouch.

October 2014: I tried a shadetree mechanic to save a few bucks on replacing the rear shocks (worn out), right front lower control arm and engine mounts. He screwed it up by failing to tighten a nut on the wheel hub, resulting in a destroyed hub bearing assembly. He also couldn’t get the left engine mount in, so he handed me the part and said, “It’s OK, the right one usually wears out first anyway.” Later I discovered he’d left a wrench under the third row seats, which jammed them until one day the wrench rolled out.

The car ended up at the dealership to finish/correct the work.  Between the hack mechanic and the dealer, the total cost for this debacle was about $3,500 in parts and labor. That included a lot of parts, but still, double ouch. I kept the wrench.

February 2015: The front air struts finally began to leak. This is pretty typical around 100k miles on these cars, sooner if they are driven in the city a lot. Front struts were about $2,000 installed. The rears should be good for a while longer, since they get less stress. We also replaced the battery for the first time.

June 2015: I noticed some weird electrical symptoms following a big rain at Alumapalooza, and went hunting. Sure enough, there was a rain leak around the brake lights that was letting water drip on to one of the very expensive computers that run the car (called a “rear Signal Acquisition Module”). I dried it out and protected the area with a towel until we could get it to the dealership for leak testing and repair.  The tech found two leaks and fixed them at a cost of $247.  Fortunately, the rear SAM survived.

September 2015: During routine service the techs discovered the front propeller shaft (part of the all wheel drive system) had a torn boot and was leaking grease.  There was also an oil leak from the engine.  The oil leak was fixed by replacing two missing screws, but the propeller shaft had to be entirely replaced.  $1,300 for both jobs.

We also finally had to replace the front brakes. They were original brakes!  Normally on a GL most people get about 35,000-45,000 miles, so the Service Advisor did a double-take when he saw we had 107,000 miles on the car. It’s because of the towing, actually.  The Airstream’s excellent disc brakes do most of the work, saving the expensive Mercedes brakes. The dealer price for the front brakes was $551.

OK, so are you falling over with sticker shock or not? The reality of traveling as much as we do and maintaining this car to a high standard is that there’s a definite cost. We spent $5,328 on repairs in 2014, and $4,098 in 2015 (so far), not counting tires, oil changes, battery, etc. That’s over about 17,000 miles of travel, or about $0.55 per mile. It’s a high number but keep in mind we work this machine hard.

Also, the car is paid for, and we like it. Having no monthly payment compensates for a lot of repairs. Realistically, I couldn’t replace the GL320 with anything comparable or more reliable for what we spend on repairs currently*, so economically it makes sense to stick with it.

* For reference, our current repair budget is equivalent to the payment on a $22,000 vehicle financed at 4% for five years.

For me, the key factor is overall reliability. While the car has spent some time in the shop getting replacement parts, those have been planned services. It has never failed us on the road. That’s my personal Rubicon to cross; if the car fails to get us where we are going, I’ll take it out behind the barn and shoot it.  I don’t mind maintenance and replacing worn parts as long as it continues to perform as good as new, but becoming unpredictable and unreliable would put an end to our friendly relationship.

Interestingly, none of the repairs we have had in the first 100,000 miles can be attributed to the “stress of towing.”  A lot of armchair/Internet experts will claim that towing is terribly hard on a vehicle. Our experience has been the opposite. All the highway miles have only lengthened the time certain parts have lasted (front struts and front brakes in particular), and we have had no repairs that can be attributed to towing.

The engine and transmission have yet to show any significant problems at all despite pulling a trailer that typically weighs about 98% of the manufacturer’s suggested tow rating. I have gained a lot of confidence in Mercedes’ design for this V6 Turbodiesel engine. It will probably be the last thing to fail.

I do expect we’ll probably be buying rear air struts and front suspension components in 2016 just due to age and miles, so the budget for annual maintenance will likely stay around $4,000-5,000.  If it gets substantially higher, I’ll start thinking about options for replacement. But for now I’m still aiming to hit 250,000 miles.