Common Problems

The vast majority of W210 owners have very few or only minor problems with their Benzes. Most of the issues these cars have, if any, are minor and best described as irritations. Some the issues are far more serious, but are relatively rare. Here’s a list of some of the common and not-so-common problems with the W210 E-class.

Major Problems

Rust

Some of the E-classes made it out of the factory without propery body panel sealing. This leads to rust in short order — not exactly something you want to see on your shiny Mercedes! The rust is usually pretty easy to spot if you know where to look. When inspecting a prospective car for purchase, look for rust:

  • Under the door seals — Peal back the inside edge of the door seals and look for rust.
  • On the trunk lid around the latch
  • Front spring perch (rare, but serious safety issue! 4Matics not affected) — Rust in the inner fender due to improper sealing weakens the attachment for the front coil spring. If the rust is severe, the spring perch may tear away from the body. If this breaks free at 90 MPH on the interstate, the aftermath won’t be pretty. Turn the wheel all the way each direction and stick your head in the front wheel well to inspect for rust. If there’s no rust, you should be okay. Taking a few moments to check for spring perch rust before you buy should help keep your entrails off the pavement.

Harmonic Balancer: 1998 to 2002 V6 and V8 models only

The main crankshaft pulley on the front of the engine, called the harmonic balancer, on the 1998 to 2002 V6s and V8s deteriorates with age and mileage. If the pulley wears out, it will slide out of position and grind its way through the front of the engine (timing chain cover), the oil pan, and possibly destroy the radiator. Not good for morale, since several thousand dollars to fix all the damage!

The good news is that replacing the pulley before it flies apart only costs $150-$250. The signs of failure are obvious. Check the pulley for separation of the rubber insert from the main body. If it appears to be coming apart, tow it (don’t drive) it to the shop and get it replaced.

Mercedes issued a recall on the harmonic balancer last year. Although the replacement harmonic balancer has been redesigned, there are some reports of it failing as well. Plan to replace the harmonic balancer every 60,000 miles or so. A little preventative maintenance goes a long way.

Head Gasket: 1996 & 1997 E320 only

The head gasket is the Achilles’ Heel of the otherwise superb M104 3.2L engine in the 1996 & 1997 E320. The head gasket tends to develop a leak every 70,000 to 100,000 miles. Usually the leak is visible on the outside of the motor. It’s important to fix this to avoid mixing coolant & oil. Plan to spend about $1100-$2000 to have this replaced, depending on the shop.

Intermediate Problems

Window Regulators

This is like a chapter straight out of A Tale of Two Junkyards. Go to an American junkyard, and you’ll find mountains of cars with blown engines and fully operational power windows. Take a trip to a German junkyard, and you’ll find mountains of Mercedes with healthy engines and broken windows.

In case I wasn’t clear, the power windows are a trouble spot on the W210 and most all Mercedes. The window regulators — the part that connects the window motor to the window glass — are poorly designed, particularly the ones in the rear. They break often. When they break, the window glass falls down into the door and you can’t get it back up. Plastic and duct tape don’t belong on a Mercedes, so it’s not something you can postpone fixing.

If you use your rear windows regularly, you’ll probably be replacing the regulators frequently. The part costs $80, and if you’re slightly mechanically inclined, you can replace it yourself. Otherwise it’ll cost you about $200-$300 each time. It’s financially prudent to avoid rolling down the rear windows.

A/C Receiver-Drier (rare), Compressor (rarer), or Evaporator (very rare) leaks

If and when they conspire, the rear window regulators and a leaky A/C have real potential to make you a sweaty mess. The A/C receiver-drier removes moisture and contaminants from the air conditioning system. Think of it like a filter. If your A/C won’t hold a charge, it’s likely the receiver-drier that’s leaking. Replacing this part is inexpensive.

If you’re an unlucky person, you may at some point have a leaky A/C compressor. The A/C compressor part costs about $600. Any time you crack open the system, you must also replace the receiver-drier. Parts and labor for a new compressor will run you about $1100. Compressor failure isn’t too common.

If you’re really, really unlucky, your A/C evaporator may develop a leak. This isn’t a nightmare to replace like the S-class evaporator. More like a bad dream. Replacement involves removing the dash. Leaks in the evaporator are rare enough that I feel bad about listing it here. Might scare you or something.

Wet Transmission Control Module

The quick disconnect on the transmission wiring harness sometimes leaks fluid. The fluid gets pressurized and shot up through the bundles of wires into the transmission control module. Voila! You have a flooded transmission control unit. It’s important to periodically inspect this to make sure it’s not leaking. If it is, you can often inexpensively repair the problem by replacing the harness. If the fluid fries your control unit, plan on shelling out some money.

Catalytic Converters

The catalytic converters have a procilivity to wear out after about 60,000 to 100,000 miles. The catalyst material inside breaks apart and rattles around inside the body of the converter like loose marbles. If the cats clog, the exhaust backpressure can hurt your engine. You can tell your cat needs replacement if you can hear what sounds like marbles rattling when your engine is running. Replacement catalytic converters cost about $800 for each side from the dealer

Note that sometimes the weld on a small bracket further down the exhaust pipe may break, causing the pipe to rattle and transmitting the noise along the pipe. The broken weld may be very difficult to spot. The sound of this broken bracket may mimic that of failed catalytic converters. The broken bracket can be rewelded by a muffler shop inexpensively.

Mass Airflow Sensor

The mass airflow (MAF) sensor is a small plastic tube with a sensor that fits between the air cleaner box and the intake manifold. This little $300 gem measures the amount of air flowing into the engine to properly set air-fuel mixture for best performance & economy. The sensor typically fails about every 80,000 miles on both diesel and gas W210s. A bad MAF manifests itself with a check engine light (and a more specific computer trouble code) and a very poorly running engine. Sometimes the sensor malfunctions because it is dirty, which can be fixed by a good cleaning. Performance oil-medium air filters like K&N exacerbate the problem because (1) they tend to let more dirt through and (2) they tend to coat the sensor with filter oil.

Although it may be tempting to install a K&N air filter, don’t. The Mercedes air box is well-designed, so the performance gains will be negligible. Moreover, you run the risk of damaging your mass airflow sensor, or worse, your engine. Many people who have their used oil analyzed find higher than normal levels of dirt in the oil (which presumably enters through the intake) when running K&N filters.

Irritations

Squeaky, Creaky Seats

The front seat frames creak on some cars. Unfortunately, replacement frames/rails are expensive. If this bothers you, you’re probably best off rigging something up yourself to tighten it.

Squeaky Power Steering

As one of the bushings on the power steering box wears, it transmits a groan up the steering column every time you turn. The bushing can be replaced, although some dealers may try to sell you a new power steering unit. If you’re looking only to replace the bushing, it’s probably best not to show up wearing your most expensive suit.

Front Sway Bar Links

The front sway bar links wear out somewhat quickly. When worn out, they cause a rattling noise every time you hit bump. You can replace them yourself for about $20 per side.

Sunroof Rattle

The sunroof guides are attached with only one screw on each side. This often rattles and can interfere with the sunroof operation. They should be attached with two screws. The dealer charges a lot of money to put in a second screw. Fix it yourself for less than a dollar.

A/C Blower Regulator

The electronic part that controls the fan speed of the heater and air conditioner fan often burns out in pre-facelift W210s. Mercedes changed the fan design and no longer makes the old regulator. Upgrading the fan and regulator to the newer design costs about $1,000. Inexpensive workaround: the blower regulator from the W140 S-class is a compatible replacement, but its wires are too short. Swap the wiring harnesses with your burned out regulator and install. Total cost: ~$150 and about 45 minutes of your time.

Burned-out Lights

For reasons only explainable by Gottlieb Daimler and Karl Benz, the exterior lightbulbs on some E-class cars like to burn out on what sometimes seems like a weekly schedule. Perhaps its a conspiracy with the lightbulb manufactuers. In any case, the rear taillights tend to be particularly frequent offenders.

Brake Switch

Multiple switches in the brake pedal detect when you apply the brakes. If one of those switches fails, your dash will light up like a Christmas tree with all sorts of errors for the brake assist, traction control and stability control systems when you step on the brake. While uninformed E-class owners may panic about a huge repair bill, well-read people like you will know that the culprit is simply an inexpensive switch that takes only a few minutes to replace.

Rear Brake Rotor Warpage

Mercedes under-spec’d the rear brake rotors. Consequently, they tend to warp prematurely. When they warp, the best solution is to replace the rear rotors with Brembo high performance rotors. The cost is about the same as the replacing with the warp-prone OEM rotors.