About this model
The second-generation Mercedes-Benz ML (W164) was produced from 2005 to 2011 and in BiH it sells almost exclusively as an import from Germany and Austria. The most common variant on our market is the ML 320 CDI with the 3.0 V6 diesel engine (OM642) and the 7G-Tronic automatic, a status SUV bought in a wide price range depending on mileage and equipment. The typical owner is a family doing up to 25,000 km a year, plus quite a few units with air suspension bought for towing trailers and boats. The W164 has serious equipment for its age (Comand system, leather, xenon, parking sensors), but it demands serious maintenance, this is not a car for a buyer who avoids the workshop.
Engines and variants
In BiH this model is most often available with the following engines.
OM642.940 (3.0 V6 CDI, 224 hp) - the basic 3.0 V6 CDI variant with 224 horsepower and 510 Nm of torque, paired with the 7G-Tronic automatic, model years 2005-2009 (pre-facelift). This is the variant most affected by oil cooler and swirl flap issues because it has more years behind it, but parts are available and the mechanicals are familiar to every serious workshop in Banja Luka. The typical buyer is a driver who consciously chose an older, better-equipped year over a newer but stripped-down SUV.
OM642.940 facelift (BlueEfficiency, 224 hp) - the facelift version from 2009-2011, same mechanicals but with an upgraded DPF system and minor software revisions. Fewer issues with swirl flaps because Mercedes revised the plastic seals, but the DPF is stricter and slips into forced regeneration more easily, especially with city driving. Prices of these examples are noticeably higher than the pre-facelifts and there are fewer of them on our market.
OM642 ML 280/300 CDI (190 hp) - the weaker version of the same V6 engine with 190 hp, model years 2005-2011. Less common in BiH but it exists. Mechanically it is the same engine with the same flaws (oil cooler, swirl flaps), just with a less aggressive turbo, so it is a bit easier on the turbocharger and intercooler. Fuel consumption is closer to the 224 hp version than you would expect, the difference in practice is barely half a litre.
Reliability and reputation on the BiH market
The ML W164 is a car that aged well on German motorways but had a harder time on Bosnian streets. The body is solid and does not catch rust like the older ML, but the chassis takes a beating over potholes, every two years the control arm links, ball joints and wheel bearings need a check. In the workshop we most often see the front suspension being the first thing that needs investment after buying an imported example.
Parts for the OM642 engine and 7G-Tronic are available, there are also quality aftermarket alternatives (Febi, Meyle, Mahle), but you have to watch out for non-original injectors and valve body conductor plates, that is the area where people save in the wrong place and the result is another visit to the workshop in a few months. Compared with the BMW X5 E70 and Audi Q7 4L from the same period, the ML is technically similar but more accessible to maintain than the Q7, while the X5 and ML are roughly equal in running costs. The typical buyer in BiH is a person who does not walk into the first showroom and who knows that a status car requires a status budget for maintenance, anyone who does not understand that becomes disappointed with the W164 very quickly.
Common faults we see
From our practice, here is what most often comes in for repair on this model.
1. Oil cooler leak - the well-known OM642 weak spot
Symptom: Oil seeps over the V-joint of the engine, most often visible as an oily film on the back of the engine when viewed from underneath. In worse cases the oil level drops quickly, a smell of overheated oil appears in the cabin and deposits build up on the turbocharger.
The rubber seals between the oil cooler and the block harden from heat cycles and start to leak. This is the Achilles heel of the OM642 V6 engine and sooner or later it affects practically every example over 150,000 km. The job is labour-intensive because the intake manifold has to come off, so when the car is on the lift this job is rarely done in isolation.
Advice: When you already have the engine open for the oil cooler seals, tackle the swirl flaps at the same time and clean the intake, you save twice the work in the long run.
2. Swirl flaps in the intake manifold
Symptom: Fault code P2015 or 2602/3052/3053, loss of power, going into limp mode, uneven idle. When the intake is opened up you find oily black sludge and broken plastic flap shafts.
The flaps are mounted on a plastic shaft that wears out over time, the flap actuator motor gets contaminated by oil from the oil cooler leak and burns out. It typically pops up in the 180,000-250,000 km range, depending on driving style and service history, more often on cars driven mostly on short trips.
Advice: The most reliable solution is a mechanical removal of the flaps (closing the openings) plus electronic disabling of the motor in software, never a bypass resistor that feeds the ECU a false signal.
3. Piezo injectors on the OM642
Symptom: Hard cold start, grey-white smoke at start-up, uneven idle with a knocking cylinder, fuel return (Mengentest) out of tolerance, smell of diesel when you open the bonnet.
The OM642 uses piezo injectors that are sensitive to fuel quality and high rail pressures. In BiH, where fuel can be of lower quality, the injectors start to leak or lose atomisation in the 200,000-280,000 km range, depending on fuel quality and oil change intervals. Copper seals often "eat" into the injector and when you try to pull it out the injector seizes in the head.
Advice: Measure fuel return (Mengentest) every two years as a preventive check, and at the first sign of trouble do not keep driving for long, one leaking injector quickly dilutes fuel into the oil and damages the turbocharger and DPF.
4. Airmatic air suspension (Airmatic ADS)
Symptom: The car leans to one side after sitting overnight, the compressor runs too long or constantly, message "Air Suspension - Vehicle too low - Stop the car", a difference in height between left and right side.
The version with Airmatic (an option on the ML 320 CDI) has two typical faults, a punctured air spring bellows (most often at the rear) and a worn compressor that no longer holds pressure. The bellows splits along its fold from salt and UV exposure, the compressor burns out because it works too hard trying to compensate for the leak.
Advice: When buying a car with Airmatic, leave it switched off for 8-12 hours and come back in the morning, if it is still level, the bellows and compressor are healthy. Otherwise the repair is expensive and we recommend the steel-spring version if you can choose.
5. 7G-Tronic automatic gearbox (722.9) - conductor plate and oil
Symptom: Jerks shifting from second to third when cold, hesitation when pulling away, occasionally a "dead" D or R, fault on the gearbox electronics, some vehicles drop into limp with a fixed gear.
The 722.9 7G-Tronic is generally a solid gearbox, but the conductor plate (valve body with speed sensors and electrical connector) is prone to oil seeping into the connector and to faults. Mercedes long claimed it was "lifetime" oil, which in BiH conditions simply is not true, short trips and heat cycles degrade ATF faster than the specification predicts.
Advice: Our recommendation is a gearbox oil service every 60,000-80,000 km with replacement of the filter and pan, that is the cheapest insurance for the 7G-Tronic. The conductor plate is a standard service part when a fault comes up, you do not need to replace the entire gearbox.
6. DPF and EGR system - clogging from short trips
Symptom: DPF warning light, occasional loss of power, increased fuel consumption, regeneration interrupted, oily black deposits when the EGR valve is opened, occasional fault P0401 or P244B.
The car weighs more than two tonnes, the OM642 produces a lot of soot on short trips, and the DPF needs exhaust temperature to regenerate. Owners who drive their ML mostly in town (status car, not motorway) quickly clog both the DPF and the EGR. The EGR cooler can also crack and pump coolant into the intake, which is diagnosed by pressurising the cooling system.
Advice: The ML 320 CDI is not a city car, if you are not regularly doing trips longer than 30-40 minutes, this engine will not last long. EGR cleaning at 100,000 km and DPF diagnostics every year are the reality with this car.
7. Timing chain - tensioner and guides
Symptom: Rattle in the first few seconds at cold start, later a noise at idle on a warm engine, occasional crankshaft/camshaft timing position fault.
The OM642 has a timing chain that nominally lasts the engine's lifetime, but the plastic guides and the hydraulic tensioner show signs of ageing past 250,000 km, especially on engines that have been starved of oil or run on overly extended service intervals.
Advice: When the chain is suspect, check with a dial indicator and endoscope, removing the front timing cover is a big job and is not done "just in case". Often it is enough to just replace the tensioner and guides without pulling the chain itself.
8. Turbocharger and intercooler - leaks on the hoses
Symptom: Loss of power above 2500 rpm, bluish smoke under load, hissing during acceleration, oil bubbles in the intercooler or on the hoses.
The Garrett VGT turbocharger on the ML 320 CDI is solid, but the silicone intercooler hoses split along their folds and start blowing oil. The turbine vanes stick from soot on cars that are not given a regular "Italian tune-up", in practice the solution is a good thermal drive once a month and boost pressure diagnostics at the first symptoms.
Mercedes ML fault code P2015
P2015 is the best-known fault code on the ML 320 CDI and is directly linked to the swirl flaps in the intake manifold. The code is thrown when the ECU detects that the flap actuator motor is not moving the shaft on command (most often because the shaft has broken or the motor is dead). In practice this fault comes packaged with a loss of power and entry into limp mode above 2500 rpm, so P2015 is the number one reason for booking an appointment with us. The solution is mechanical removal of the flaps plus software deactivation, as described in point 2.
Service and maintenance
The timing drive is a chain, nominally with no service interval, but an inspection at 200,000 km is reasonable, especially if the car has a history of extended oil change intervals. Engine oil every 10,000 km with specification MB 229.51 or 229.52, viscosity 5W-30, never the extended "longlife" interval of 25,000 km that Mercedes once advertised, Bosnian short trips and fuel quality cannot handle it. 7G-Tronic gearbox oil every 60,000-80,000 km with pan and filter (original red ATF oil MB 236.14 or 236.15), depending on driving style and operating conditions. DPF diagnostics every 30,000 km and EGR cleaning at the first symptoms.
7G-Tronic 722.9 oil service
A 7G-Tronic gearbox oil service is not a simple oil change, it includes a complete new pan, a new filter inside the pan, a new connector seal and roughly 7-9 litres of MB 236.14/15 ATF. Mercedes told us for generations that the 722.9 has "lifetime oil", but in the BiH climate and with our way of driving that simply does not hold up, we see ATF that after 100,000 km is black and smells burnt. Our recommendation is an interval of 60,000-80,000 km, even when the gearbox is working without problems.
Owner tips
- Before buying a specific example: use the VIN to pull the full history of the car via carVertical. From international registries it usually shows real odometer figures by date, recorded accidents, the number of previous owners and indicators of theft or total loss. We consider it mandatory before buying any used car, and especially with German imports like the W164. When paying for the report you can use the code GAGA for a 20% discount.
- Every two months check the back of the engine from underneath - early detection of an oil cooler leak saves a lot of work and prevents major damage to the swirl flap actuator.
- Change 5W-30 oil to MB 229.51 or 229.52 specification at 10,000 km, not the 25,000 km printed in the service book, Bosnian short trips do not handle "longlife".
- Measure fuel return (Mengentest) every two years, that is a preventive injector check that costs an hour or two of labour and can prevent serious damage to the turbo and DPF.
- If you are buying an ML with Airmatic, definitely leave the car overnight and in the morning check for any lean, that is the most honest test of the air suspension's condition.
- Service the 7G-Tronic gearbox oil every 60-80,000 km with pan and filter replacement, that is the cheapest insurance against major gearbox failures.
Frequently asked questions
Is the ML W164 320 CDI reliable for 300,000 km?
Yes, but only if it is serviced regularly and if the known weak spots are addressed in time, oil cooler, swirl flaps and gearbox oil. A car that has been starved of servicing very rarely passes 250,000 km without a major investment. Our recommendation is to factor in a preventive service straight after purchase, do not buy an ML and then start thinking about it next summer.
What is the realistic fuel consumption of the ML 320 CDI in BiH?
In town expect 11-13 litres, combined 9-10, on the open road 8-9 litres of diesel per 100 kilometres. The version with Airmatic and 19-inch wheels uses noticeably more than the basic one. If you are looking at the ML purely for status, know that it is not a car for 6.5 litres of consumption like a compact-class hatchback.
Is it worth fitting LPG on an ML 320 CDI?
No, it is a diesel engine, and LPG (auto-gas) is fitted only on petrol engines. On diesel MLs people use a dual-fuel diesel+gas system instead of LPG, which in BiH is not economically viable for private users and we generally do not recommend it.
Which ML W164 should you avoid when buying?
Avoid examples with Airmatic if you cannot verify that the system holds pressure overnight, examples without a documented service history (especially for the 7G-Tronic), and those with the AdBlue system from the latest model years if they are imports, AdBlue diagnostics here can be complicated. Look for an example with steel springs and without the rear extra system.
How much does a swirl flap and oil cooler service cost?
The price depends on the specific condition and scope of work, and these two jobs are generally done together because the intake manifold has to come off anyway. For an accurate on-the-spot estimate get in touch for a quote, it is better to see the engine in person than to estimate blindly.
Does the ML 7G-Tronic hold up to high mileage?
It does, but on the condition that the oil and conductor plate are serviced on time. The 722.9 7G-Tronic passes 350,000 km without major overhauls when the oil is changed every 60-80,000 km. The biggest mistake is to believe Mercedes' old story that the "oil is lifetime", it is not and never was.
ML W164 or BMW X5 E70 - which is the better choice for BiH?
Technically they are very close, both engines (OM642 and M57N2 in the X5 30d) require similar maintenance and have similar problems, timing chain, injectors, DPF. The ML is somewhat more accessible to service and has a simpler electronics package, the X5 drives more sportily but has more expensive tyres and higher fuel consumption. For BiH roads and family use we lean towards the ML.
If you notice any of these symptoms on your W164, drop by the workshop, it is better to check early than to pay for an expensive repair.