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Full Test: 2000 Mercedes Benz ML55
Speed-Utility Vehicle
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By Miles Cook
Date posted: 01-01-1999
Does the "fastest sport-utility vehicle in the world" really need to exist? Judging, these days, from all the other outrageous things that occur in the automotive world, we'd wager the answer is yes, an all-hangin'-out SUV needs to be available to those who desire such a conveyance.
What better car/SUV maker to offer such an animal than Mercedes-Benz with its AMG division. Like the BMW M Division or the Special Vehicle Team (SVT) within Ford, AMG is the high-end, be-all-end-all group that turns out no-compromise cars with the three-pointed star on the hood.
Trouble is, while AMG's ML55 has some amazing attributes—namely its rowdy 5.4-liter V8—it suffers from too many compromises to be truly worth its near $70,000 price of admission. Besides its shortcomings, there are things to recommend about it. Just remember that 70 large is a pot full of dough, even for cars or sport-utes much better than the ML55.
As we just said, it's the engine that really floats our boat. Packing 332 cubes of serious earth-rotating power, the 24-valve V8 (that's three valves per cylinder) delivers to the tune of 342 horsepower at 5,500 rpm and a stout 376 foot-pounds of torque at 3,000 rpm. How impressive is this motor? Well, for starters, it's making more than one horsepower per cubic inch, a notable feat for any internal combustion engine. It also matches current V8 heavyweights such as the C5 Corvette's LS1 V8 that makes 345 ponies and surpasses such others as the Ford SVT Mustang Cobra that was optimistically rated at 320 horsepower.
Making its debut in the '99 SL500 roadster, this engine is the result of one of the most tried-and-true hot rodding tricks up an engine builder's sleeve. Starting out as a 5.0-liter engine, the 5.4-liter displacement comes from a stroker crank that provides an added one-third inch stroke, or 8 millimeters if your thinking is metric. The forged-steel crank (a bulletproof piece, probably good for about 600 horsepower) is connected to weight-matched sets of connecting rods and pistons.
To get more air into the stroker V8, AMG updates the magnesium intake with a wider cross section to increase flow. There's also a special butterfly system inside the manifold that redirects airflow below around 3,700 rpm, forcing the air charge through longer runners, improving low and mid-range power. Above 3,700 the butterflies open, allowing the air charge to take a shorter, more direct route to the combustion chambers for optimum high-speed power.
In addition, the ML55 has a unique computer processor, different from lesser ML320s and 430s, to control larger fuel injectors. The AMG engine for the ML55 retains its twin spark plug/three-valve, SOHC design, but replaces the standard cams with modular units that work in conjunction with stiffer valvesprings. The AMG-spec cams also have a longer duration that helps to increase power output.
Behind the engine is a five-speed automatic transmission that continuously networks electronically with the engine and chassis management systems. This allows the trans computer to adapt to a wide variety of driving situations and even to a driver's individual style. One of the more sophisticated systems on the ML55, the transmission's processor retards ignition timing for a fractional second for smooth, and some might say mushy, shifts. By comparing vehicle speed changes and throttle openings, the transmission computer can discern uphill and downhill grades and adjust shifting as a result. It avoids annoying shifts back and forth between two gears on an uphill and delays downshifts on descents for engine braking (as one would do with a manual transmission). The trans computer also measures how fast the driver presses and releases the gas pedal. Of course, really standing on it causes firm downshifts. But beyond that, upshifts are less likely when the pedal is released suddenly. With smaller throttle openings, the transmission shifts according to a basic program that's tuned to provide optimum fuel mileage, an area in which the burly engine can use all the help it can get. The transmission computer is also linked to the electronic traction control and AWD system so that it can recognize cornering and low-traction conditions. Based on acquired data, the gearbox may hasten or delay a gear change to ensure there's no negative effect on traction.
Besides the engine and transmission, the ML's independent rear suspension (IRS) is uncommon in the world of SUVs. The design consists of a double-wishbone arrangement similar to the system used up front. But while the front uses torsion bars, the rear has progressive-rate coil springs. As in the front, the upper control arms and the springs and shocks are connected to the ML's frame, while the lower arms and anti-sway bar are hooked to the subframe. Both upper and lower arms are forged aluminum.
Stepping inside the ML55 the look is very inviting, but the function fails miserably to live up to the form. One of our more notable gripes is with the Modular Control System (MCS). While the CD ROM-based navigation system works well once you learn the basics, the controls for the radio and nav system are quite difficult to access. For example, the volume control for the radio/CD player is on the far right of the head unit. What's the deal with that?! Is this a Japanese, British, or Australian market transplant? We found it extremely irritating to have to reach all the way over to the far side of the dash just to raise or lower the volume output. The most commonly used control on the head unit should simply be more—much more—accessible to the driver. The volume control and the keypad should be swapped with the low-range AWD and fog light switches. These controls almost never get used by comparison. As a matter of fact we tried out the low range only once during the entire week we had the ML55. How many times did we utilize the volume control for the radio? Quite often each time we drove the car, that's for sure.
Furthermore, there are no steering wheel-mounted controls for the radio (or cruise control; the latter is mounted on a flimsy stalk that gets in the way when you use the turn signals). Our long-term Jeep Grand Cherokee not only has steering-wheel controls for the radio, but they're the best we've ever encountered on any vehicle. And it costs less than half the price of the ML55 to boot. Also consider this for a moment: the JGC and the ML55 are made by the same parent company! Completely baffling, in our humble estimation.
We noted numerous other ergonomic sins inside the ML55 and almost don't know where to start. One of our scribes noted that he could use the MCS system, but couldn't stand the joystick button combination that you have to use to navigate through the on-screen menus. "Pushing that little joystick to enter your desired commands without having the joystick slide sideways and move the cursor is way too difficult. Most of the MCS I can deal with, but this control system is clunky and needs to be changed."
Other editors commented on the lack of basic features in the ML's cabin. "Too much money, too few features," executive editor Brauer carped. He elaborates: "Where are the one-touch up and down windows all around? Our $37,000 BMW 328i has them. How about steering wheel controls, automatic climate control and power seat controls that are mounted in clear view on the door panels like on every other $50,000-plus Benz? Why is there no DVD-based navigation system like Lexus and Honda have?" We'll sum up our dismal impressions of this SUV's interior snafus with what another staffer calls "usual complaints about the ML, such as dopey stereo/navigation ergonomics and cheap parts that don't even match a Corolla in terms of fluid operation and movement."
We realize that buyers of the ML55 may not give rat's fanny about where the radio controls are located or the lack of cushy features like auto-up and -down windows. And when the subject turns to the gas pedal having an intimate relationship with the floor's carpeting we almost forget about those things, too. You can bet your bottom dollar that this thing is the fastest factory SUV money can buy; we found that out the fun and safe way during our test session. Sixty mph is served up in a scant 6.7 seconds and the 1320 is dispatched in 15.1 seconds at 93 mph. For a vehicle weighing nearly 5,000 pounds, that's indeed pretty swift and it's also enough oats to dust off any kid who thinks he's a hero in, say, a Mustang GT convertible with an automatic transmission.
Other objective performance numbers are worthy of a look, too, as the ML made its way through our 600-foot slalom at 60.1 mph and stopped from 60 mph in 129 feet. During testing we noticed a lot of pedal travel and one editor thought it felt a bit truck-like for his tastes. Pulling nearly .80g on the skidpad is decent for any vehicle and this SUV-based hot rod delivers checking in with a figure of .78.
But these numbers are merely a black-and-white yardstick and subjective observations are always shrouded in several shades of gray. There, the ML gets mixed reviews when passed around to the various editors on our staff. Our time with the ML was mostly relished when we pointed it down a freeway on-ramp and flat-footed the pedal all the way through third gear and up to 85-90 mph. That's when you feel every bit of those 332 cubic inches as you smile all the way to extralegal velocities.
Other comments about the ML's driving dynamics were not so kind. Some felt the ride was harsh and its handling was not very confidence inspiring. Body roll is notable for what's supposed to be the most performance-oriented SUV on the market. More than one editor commented on the overboosted power steering. Another driver felt the steering lacked usable feedback, much like a truck, while yet another said, "it effectively Novocain's road feel."
Driving impressions and interior problems aside, the actual utilitarian value of the ML55 is pretty decent. With the seats up in back, there's 44.7 cubic feet of cargo volume. With the seats down, it nearly doubles to 85.4. If only that darn spare tire wasn't in the way, then it'd be even better. Furthermore, towing capacity is impressive and when outfitted with an optional Class III hitch, the ML55 will tow 5,000 pounds.
After reading our rants and raves you'd probably surmise that we dislike the ML55 and think it's a complete strikeout. Yes, it has some serious flaws that other less expensive utility vehicles just don't have. In the final analysis, we'd probably have to recommend the BMW X5 over the ML to just about anyone comparing the two, since we have trouble justifying in our own minds, let alone recommending that others pay its asking price of nearly 70 grand.
But in some ways we have an affinity for the ML that's mostly bolstered by its fantastic V8 furnace, breathed on by the gearheads at AMG. If you must have an SUV that's the fastest in the land, without the aftermarket getting its hand involved, then the ML is the only choice. Just be sure you drive the nearly-as-fast X5 first before plunking down those greenbacks—and don't say we didn't warn you about our already-emerging fantasies of a BMW M version of the X5 that'll almost certainly put the ML55 to shame.
Town Hall Commentary from Owners:
545 of 657: My ML55AMG Pictures… (mbml55amg) Tue 01 Feb '00 (05:37 PM)
The ML55 is everything I expected it to be, it's hard for me to separate the 2K M Class upgrades from the ML55 upgrades since I own the 99 Ml430, but the 55 is in another class. The steering, power, HID lighting &seats are way better than my ML430's. The steering is feather light @ parking lot speeds, yet very firm @ freeway speeds. The power doesn't seem all that different from the ML430 off the line, but @ 20-30 mph it is awesome. The greatest difference in power however is @ 55-70 mph, when you decide to pass, it does so &I mean RIGHT NOW. The looks are just right, &the Bordeaux/Charcoal complement one another very well. I hope MB will offer the ML55 flare &body enhancement package as an option on all MLs soon. I was glad to see the bumpers painted to match on the 320 this year, &hope the "Sports Package" will be available soon with the ML55 look on all MLs. I wonder if the ML430 will receive dual exhausts soon, or at least the fuel tank upgrade. If you get an opportunity, drive the ML55, it is a spectacular vehicle.
#476 of 549: ML55 fuel consumption (bobfra) Thu 13 Apr '00 (03:12 AM)
(…) What should I mention first? The incredible performance of this monster or how incredible the fuel economy (?) is. OK, OK, I get a whopping 14 mpg. When I called my dealer, the first thing that he asked me was "Did you get any speeding tickets yet?" He said the engine was tuned for performance, NOT fuel economy. If the engine craves more fuel, the computer does not tell it that it has to be a little more frugal with the fuel . It gives it all it wants! Consequently, you step on the pedal and it pushes you back into your seat. It is rated to go 0 - 60 in 6.4 seconds.
615 of 644: ML55 is da bomb (bobfra) Fri 05 May '00 (08:54 AM)
I've had my ML55 for almost 2 months now with 1400 miles. The only problem I had was the stuff on the front passenger window that other people said they had. Some people said they thought it was glue. It appeared to me to be white grease. Dealer removed door panel and resolved the issue. I have no rattles or creaks. The truck seems to be very solidly built. But of course for $66,000 ……
Anyway, it easily goes 100+ mph. To be honest, I don't have the nerve to see if it goes the rated 150 mph. I LOVE the xenon headlights!! MB really should make them an option. I have them on both my Y2K S500 and ML55. No question, I would buy xenon again! It is too easy to overdrive the quartz lights. My S500 has a switch that changes the feel of the suspension. Push it and it is in "sport mode". Even though my ML55 has been tuned by AMG to give a sporty ride, I still wish it had a setting that I could switch it to a firmer ride for better cornering for the times I am able to drive more "spirited". (…)
82 of 181: Vanessa's right… (mbml55amg) Wed 28 Jun '00 (08:07 PM)
The peace you get when driving the M CLass in inclement weather with your family aboard is priceless. Knowing that the many computers will respond so much more quickly than you could when an unforseen obstacle requires an emergency avoidance tactic that would upset &ultimately end in disaster if you were piloting almost any other vehicle. How much is it worth to drive the safest SUV?? Well, much more than the price of my ML55, I'm sure of that!
See all the Ratings: 2000 Mercedes-Benz ML55 AMG 4 Dr ML55 AWD Wagon Road Test Scoreboard
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