Mercedes-Benz is the oldest car manufacturer in the world, producing the first ever car in 1885. From there they have developed a great reputation for reliability and build quality. Despite this, modern cars are complex, and there are some common faults recorded among Mercedes owners. 

Mercedes Benz is known for their reliability, with high ratings in WhatCar and Which surveys in recent years. They do not often top the charts, with brands such as 

Like most modern luxury brands, Mercedes are not low-maintenance cars, and you don’t want to skip scheduled maintenance items. With their dual-

 transmissions and complex turbocharged engines, they need the recommended oil and filter changes, at the least, to keep them running smoothly. 

There are not likely to be any definitive timescales to expect your Mercedes-Benz to start developing issues, but as with many cars, problems generally begin after around 7-10 years and around 100,000 miles. This is when items such as suspension arms, hydraulic engine mounts, and timing belts can need replacing.

 is that the ride is quiet, refined and free of vibrations for the passengers. To achieve this most modern premium vehicles have hydraulic engine mounts. These are oil-filled rubber dampers that are integral to the engine mounting brackets. 

Over time, the rubber wears and perishes by absorbing the engine's vibrations, causing the oil inside to leak out and further reduce its damping effect. Symptoms of this issue all relate to excessive vibration and noise from the engine. 

Another fantastic feature that enhances comfort for passengers is Mercedes' sophisticated air suspension system. It uses an air suspension strut in replacement of a traditional 

 and shock absorber to allow better ride quality and handling characteristics. 

Like the engine mounts, these air suspension components can become worn over time and start to fail. Perishing seals and rubber 

 are the usual culprits, with symptoms being unusual handling, an uneven ride height and errors from the infotainment system. 

to most automatic Mercedes vehicles in the last 10 years or so is a complex piece of engineering that enables fast gear changes and excellent efficiency. Unfortunately, they also need servicing correctly and on time to avoid damage. 

As the interval is usually 5 years or 70,000 miles, check any car you’re considering buying has had the required services, and is on time. Servicing the gearbox is quite a complex procedure, hence why many owners neglect to do it on time. 

As many Mercedes saloons and estates are rear-wheel drives, they have a separate rubber mounting at the rearmost point of the gearbox, where it connects to the propshaft. After a few years of use, this rubber mount can too begin to perish, allowing the metal portions of the mount to collide. 

This will cause a vibration and possibly more cabin noise, that will come from the floor in between the driver and passenger seat. New mounts are relatively inexpensive and not too difficult to replace. 

A problem exclusively affecting the A-Class from March 2018, the brake hose to the rear 

 is not long enough, causing strain on the connections as the suspension goes through its full range of motion. 

Mercedes issued a recall for the fault, and any Mercedes dealer will be happy to investigate and remedy it.

As Mercedes’ best-selling saloon, the C-Class is a popular sight on the road. It offers a good measure of luxury and performance, especially in the higher AMG trim levels. Here are a few common issues to look out for. 

If you notice poor economy and running with your 1.6 diesel C-Class, double-check it was not featured for a software recall. Mercedes updated the software on the car's 

, improving the driveability and emissions performance of the car. 

Affecting cars from 2014 through to 2018, you can check to see if your car, or one you are looking at buying, is affected 

Some high-performance versions of the C-Class were fitted with axle and differential mountings that were not quite up to the task of handling the C63 V8’s power, with differential mounting brackets cracking after hard acceleration. 

Software updates were rolled out to reduce the impact on the part, helping prolong its life. 

Mercedes offers a range of cars that solve multiple needs, from high performance and handling agility to comfort and refinement. If these are qualities you are looking for in your next vehicle and intend to maintain your vehicle well, a Mercedes would be a great fit. 

 can help if your car needs expensive repairs, by offering zero-interest finance plans. We have hundreds of partners 

 has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.

5 Common Mercedes Problems & How To Prevent Them

5 Problemas Comunes en Mercedes y Cómo Prevenirlos

5 häufige Mercedes-Benz-Probleme und wie man sie behebt 

 is vital to the safe operation of your engine, the radiator plays a vital part of that. BMWs are no different, with many having larger or high-performance engines, it's even more important to fix your BMW radiator and get it replaced as soon as it breaks. 

As one of the most popular BMW models, the 3 series has been in production since 1975, with each new version being more sophisticated and better to drive than the last. 

If you take your car to the garage for it to be replaced, you can expect to pay anywhere from £200-1300 for your BMW 3 Series Radiator to be replaced, depending on your exact model and age. 

The smallest BMW in the range, the 1 series, is a practical but compact hatchback. It has been in production since 2004, when the original design was acquired by BMW from the Rover acquisition. 

For a BMW 1 Series radiator replacement, you should expect to pay between £350-1100 in the UK depending on your model. 

BMW offers a few different SUV models, they started with the X5 in 1999, and have since released the X1, X2, and X3. These offer SUV styling in a smaller overall vehicle size, making them more popular in cities and urban areas. 

How do I know if my BMW radiator is bad? 

There are two main warning signs that your 

, or water being lost from the expansion tank. 

An overheating engine can be symptomatic and the cause of serious engine issues, so it’s very important to drive as little as possible if your engine is above the normal temperature level. 

Leaks can sometimes be seen, either when driving or by noticing coolant on the floor when parked. Both of these can be caused by a leaking radiator or coolant system, and can be checked by monitoring the coolant level in the expansion tank. 

Like many vehicles there are some faults that are a common occurrence among BMW owners, alongside the infamous BMW 

 are a few coolant and radiator-related problems, read on to see if your car is affected. 

Used to contain the surplus coolant, and allow a moderate pressure to build in the system, the expansion tank is located under the bonnet, generally somewhere near the radiator. 

On some BMWs, mainly from the model years 2000 to 2008, the plastic expansion tank is known to develop leaks and even split open completely. Causing at first a slow loss of 

, followed by the system draining completely. 

If you notice your coolant tank leaking coolant, there are often uprated replacements you can replace it with, that retain the standard fitment and hose connections. 

Certain high-performance BMW models from 2009 through to 2016 were fitted with the N55 engine, this is a 6-cylinder 3-litre engine fitted to many cars including the 1 Series, 3 Series, X5, and X6. 

Certain versions of these engine and model combinations came fitted from the factory with a hard plastic link pipe on top of the radiator. The material used is susceptible to becoming brittle and cracking with the vibrations of the engine. 

This can cause a significant coolant leak. Thankfully it’s a simple fix that can be done by a home mechanic. 

A common theme from the Bavarian manufacturer is using inferior quality plastic where previously durable rubber or metal was better suited. Whilst not fitted to all their cars, models from the early to mid-2000’s such as E46 3 Series and 5 Series, had a plastic water pump. 

with these cars, the effectiveness of the water pump is the first thing the mechanic should check. 

Composite (plastic with fibre reinforcement) impellers were introduced shortly after BMW became aware of the problem. 

As the radiator is a relatively cheap part, it would usually be worth fixing a BMW radiator, assuming the rest of the car is in reasonably good condition, with no major issues such as rust or mechanical faults. 

Radiators are generally expected to last the economic life of the car, up to around 15-20 years. There is an outside chance it may receive damage by road debris or whilst other work is being carried out. 

That said, on cars 15 years or older, corrosion and wear may begin to catch up, this may be the case when a performance or special edition car has been kept on the road as a classic vehicle. 

What to do if your BMW radiator is leaking 

Because the coolant system is so important to any engine, we suggest not driving the car anymore than is necessary until it can be inspected. Whilst small leaks could be dealt with, they may be an indication of an impending catastrophic failure, which could leave you stranded. 

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interest-free car repair payment with monthly installments

How Much Does A BMW Radiator Replacement Cost?

Wie viel kostet eine Autokühler-Reparatur? 

Door actuators are one of the many things used on modern cars to make them easier and more convenient to live with. In this article we’ll take a look at average costs to replace door actuators on BMWs and what causes them to fail. 

How much does it cost to repair a BMW Door Actuator? 

Thankfully, door actuators can be relatively inexpensive to replace. The parts are readily available and the labour times are not likely to exceed 1-2 hours in total. 

The biggest factor in how much a door actuator costs to replace is if you go with genuine BMW parts, or are happy to use aftermarket ones. 

One other factor is location, garages in and around London, expect to pay around 10-15% more for labour. 

It is likely if your car door won’t unlock using the remote key, or the lock button inside, that the door actuator has broken or seized. Check that the other doors still unlock and lock as they should. 

If more than one door stops working at the same time, it is unlikely both actuators have broken at the same time, after checking the fuses, consult an auto electrician to inspect the BCM or 

. There will be one in each door, including the boot lid. They contain either a small electric motor and mechanism or an electro-magnetic solenoid. 

If you have ever had a car without central locking - where you need to manually unlock and lock every door - you’ll surely appreciate the advantage of having door actuators! 

How Long Does it Take to Replace a Door Actuator? 

Because the door actuator is inside the door itself, usually the only component that needs to be removed is the door card, the upholstered covering you see on the inside of the door. 

After removing the door card, the actuator is often held in with 3 or 4 bolts and connects to the door lock mechanism with a metal or plastic clip. 

Can I replace a BMW Door Actuator Myself? 

If you have a reasonable array of tools and are comfortable with removing and replacing components then there is a good chance that you could replace your door actuator at home. 

Whilst cars differ from model to model, the general procedure to change a door actuator is: 

Because door actuators contain moving parts, there is always the possibility of things wearing out or seizing. Door actuators on older cars will have been activated thousands of times over the years and the grease lubricating them can become dry and ineffective. 

Once this happens, the motor works harder to actuate the door lock, eventually leading to it failing. 

How to Prolong the Life of Your Door Actuators 

If you notice your door locks sounding slower than then used to, creating a slow thud rather than a quick crack noise when locking or unlocking, it could be that the actuator or mechanism is lacking lubrication. 

To help prolong the actuators and make their job easier, remove the door card, and ensure all the mechanisms and links are free moving and not binding or scraping on the door frame. If possible apply some more grease to the lock mechanism and linkages. A PTFE-based spray lubricant would be best for the linkages, and a graphite lubricant for the lock itself. 

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BMW Door Actuator Replacement Cost 

Smoke from your car's exhaust can be a worrying thing to see, regardless of the colour, as it’s usually an indication of something wrong. 

The one upside of seeing said smoke, however, is that it can be very useful in diagnosing the issue, for differing problems cause different colours. 

In this blog, we’ll explain the potential causes for any colour exhaust smoke you’re likely to see. 

Even if a car is running perfectly, you may still see some light white smoke or steam from the exhaust, particularly on cold days, for the first few miles of driving. 

Older diesel-engined vehicles may also emit a small puff of black smoke upon hard acceleration, but not constantly. 

Other than those two cases, an engine that is running well should not produce visible smoke. If your car is producing smoke, pay close attention to the colour of it, as this can often tell you a lot about the nature of the underlying problem. 

What Coloured Smoke Means From an Engine 

, keep an eye out for what colour it is, this can either be done by having a friend rev the engine slightly whilst stationary, or checking behind you whilst driving. 

What causes white smoke from your exhaust? 

A little white smoke at the very start of a journey is normal, but thick consistent clouds of white smoke mean your engine is burning coolant, which tends to indicate a head gasket failure or worse. 

For more information on white smoke, we have an entire blog article about the causes and symptoms. 

. There are a few different ways this can happen, as there are multiple sealing points stopping oil from entering the engine. Likely causes include: 

In cars with turbocharged engines, this is a very common cause of oil being burnt, 

 use oil to lubricate the spinning shaft, they have seals to prevent this oil from entering the air stream into the engine. 

This is a valve that redirects exhaust gases that get past the pistons and into the crankcase (bottom half of the engine), when the system gets blocked oil can be pushed through instead of gas, and be burnt in the cylinders 

Piston rings seal the piston to the cylinder wall when worn from very high mileage and/or poor oil servicing, they then allow oil into the combustion chamber 

Another sealing component, valve guides hold the valves that allow air into the engine. When worn they allow oil into the combustion chamber.

What causes black smoke from a petrol engine? 

Large amounts of black smoke tend to indicate the fuel-air ratio is too rich - that is there is too much fuel for the amount of air entering the cylinders. This can be from either too much fuel, or not enough air. 

Too much fuel entering can be caused by the 

 not properly metering the fuel when spraying into the engine, allowing excess fuel to go unburnt and appear as black smoke.

The main job of the turbo is to increase the amount of air entering the cylinders, a fault with the turbo e.g. worn bearings or a stuck actuator, will have a dramatic effect on the amount of air entering the combustion chambers, causing air/fuel mixture that is far too rich. 

What causes black smoke from a Diesel engine? 

Diesel engines are different in their operation to petrol engines, whilst all of the issues listed above can be present in a 

, there are other causes only a diesel car will experience. 

The diesel particulate filter is a diesel-specific emissions device used to reduce the amount of soot present in an engine's exhaust gases. Soot is created as part of the diesel engine cycle, but in cars fitted with a DPF, this is trapped and converted to ash. 

 can cause visible soot to be emitted, the removal of the DPF entirely is also another cause for soot to exit the exhaust. This will usually occur on heavy acceleration. 

Every diesel car from 2009 will have a DPF - and some made before then too - check out our guide on 

What causes grey smoke from your exhaust? 

Grey smoke can be caused by a few different things, if a small amount of engine oil is being burnt, this may not present as thick black smoke but a lighter colour that looks grey in daylight. 

 use a modulator system that is powered by negative pressure. As the engine's intake manifold experiences negative pressure in most situations, gearbox modulators are sometimes connected to the intake manifold. 

If a problem occurs with the modulator, the vacuum in the intake manifold can suck transmission fluid into the intake, causing it to be ignited along with the fuel. This isn’t a very common problem and will only happen if the following conditions are met: 

Can I drive my car if the exhaust is smoking? 

If the smoke dissipates quickly after the engine has warmed up, it's probably just water vapour and the car will be okay to drive. However, if the smoke is constant, regardless of the colour, you should not drive any further than necessary, ideally to a garage or repair centre. 

Not only could the smoke-causing issue damage your engine, but it could also get you in trouble with the police if you’re obstructing the view of other drivers. 

If you can smell exhaust or fuel fumes inside the car, refrain from driving as soon as possible, finishing the journey with the windows open. Being able to smell exhaust fumes inside the car is an indication there is a significant exhaust leak. 

If you can smell exhaust or fuel fumes inside your car, take it to a mechanic or garage as soon as possible, continuing to drive could cause coughing, breathing difficulties and other long-term effects. 

, you can split the cost of repairs and services into monthly payments at no additional cost. Choose from 1000s of reliable garages and dealerships across the country.

Why Is Smoke Coming Out of My Exhaust & What The Different Colours Mean 

¿Por qué sale humo de distintos colores del tubo de escape?

Cars are complex things, and because of this, they have many different ways of telling us as drivers, when something is going wrong. Often this appears in an easy-to-see 

 or a written warning, but sometimes it’s more subtle. 

The colour of the smoke from your exhaust can be a real indicator of the health of the engine, if you have white smoke coming from your exhaust, be sure to read on. 

In an ideal world, and with a car that’s running well, you should never expect to see much from the 

Light-coloured white smoke/steam is normal especially when starting the engine on a cold day, the moisture from the air condenses in the exhaust as it heats up. The force of the exhaust gases then expels this as steam from the tailpipe. 

What Causes White Smoke from the Exhaust 

Large amounts of thick white smoke from the exhaust are usually caused by the engine burning water in the cylinders, producing steam that looks just like smoke. This can be caused by a few different issues, one of which is a 

Unfortunately, a blown head gasket is the best-case scenario for an engine producing white smoke, other causes can be from a cracked or warped engine block, or cracked cylinder head. 

White smoke coming from the exhaust in cold weather 

A small amount of white smoke when just starting the car, that dissipates into the air quickly, is usually not a sign of anything serious, it’s actually just water vapour and is usually more noticeable on colder days. 

Minimal white ‘smoke’ when the engine is cold is caused by a similar principle to us being able to see our breath on a cold winter's day; the cold humid air condenses inside the exhaust and is then turned into steam by the extremely hot exhaust gases. 

Once the exhaust has warmed up fully, the smoke will stop.

How to Check if White Smoke is Caused by a Blown Head Gasket 

If your car is producing white smoke, it may be caused by a blown head gasket. There are a few key points to check, to help diagnose the problem 

Does the smoke continue after a few minutes of driving?

If so then there’s a good chance the engine is burning coolant, through either the head gasket or a cracked cylinder head and/or block. 

Coolant should stay at a constant level, with only very minimal losses over many thousands of miles. If you’re having to top up your 

 regularly, and have constant white smoke, it’s likely your head gasket has blown. 

If you can see bubbles rising inside your expansion tank, along with the two previous symptoms, there is a strong chance the pressure inside the cylinder is pressurising the coolant system, through a break in the head gasket. 

An inexpensive test you can do at home is a block leak test, which uses a simple device to check if exhaust gases are escaping through the coolant system, a surefire sign the head gasket is blown. 

The kits are around £20 and involve adding some of the included liquid into the plastic device, then this is held over the coolant expansion tank with the engine running. Be sure to follow the instructions on the product, and never open the coolant tank when the engine is already hot. 

For more information on what a blown head gasket means for your car, read our guide 

How to Fix White Smoke Coming From Your Exhaust 

As we’ve discussed, if the white smoke or steam is thick and continues even after the engine is warm, it is likely to be a blown head gasket. You can follow the steps above to check for this. 

In the event of a blown head gasket, the engine will need substantial work at a garage, thankfully many engines can be stripped and rebuilt without the need for expensive machining work, as long as the engine hasn’t overheated severely. 

If it has overheated, though, the block and head may have been warped - resurfacing of one or both parts will then be needed, adding more time and expense to the job. 

Unfortunately, there are no real solutions to a cracked engine block that doesn't require a new engine. The cheapest way to achieve this is often with a second-hand engine from a breaker’s yard or dismantler. 

Is White Smoke from the Exhaust in Winter Normal? 

White smoke isn't always a serious issue, if the smoke/steam dissipates easily and stops after the engine is warm, it is caused purely by condensation in the exhaust. 

This is much more prominent in winter, due to the water vapour being easier to spot - just like being able to see your breath.

To conclude, white smoke from your exhaust is often seen on cold days and is generally harmless, but it’s good to be aware of what to look out for if it persists. For more information on car maintenance and car repair tips, check 

een writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Why is white smoke coming out of my exhaust?

¿Qué significa el humo blanco del tubo de escape?

Warum kommt weißer Rauch aus dem Auspuff meines Autos?

It can be easy to miss, but water leaking into your car can cause serious issues if left to worsen. Thankfully there are some telltale signs to identify when you have rainwater leaking into your car interior, and some common causes that can help identify the cause. 

If you notice any of these signs, it’s wise to investigate fully to find the cause of the leak, before it causes irreparable or expensive damage. 

An unmistakable sign that water is entering your car is if the floor mats are sodden, which is likely to be especially noticeable after heavy rain or a period of not driving the vehicle. 

It's likely if the floor mats are wet, then the carpet too will be soaked through, the extent of which can help identify where the leak has originated from. 

When water leaks in through seals, it is likely to also bring some road grime, dust and dirt. If this water soaks into your upholstery, be that the seats, carpet or headliner, it is likely to leave a discolouration. 

Usually an off-white or light brown colour, discoloured fabric is an easy way to identify where the water is entering, marks on the headliner are likely to be from a leaky sunroof, for example. 

3. Window misting or screen freezing on the inside 

Excess moisture inside a vehicle will present itself in a couple of ways, if it's particularly cold outside the vapour may condense on the inside of the 

. Alternatively, it can simply fog up the windows, requiring wiping or airing to remove. 

If your windows constantly fog up, check for other signs of leaking. Usually, the windows will fog nearer the source first, for instance, a broken boot seal will cause the rear window to fog most.

One of the most common causes of a smelly car interior is an old water leak that has not been addressed, or at least the upholstery is not sufficiently dried out. 

To remedy a mouldy-smelling interior, with no obvious leak, thoroughly clean the carpets and floor mats. Once clean and dried, monitor closely the carpets around the problem areas for dampness, especially after rain. 

If you’re experiencing strange electrical faults with no apparent cause, ruling out a water leak is a good step. Problems usually occur in cars that have the 

 located in or around footwells and by door frames. 

This is one of the most unfortunate ways to find out you have a water leak, as it may be too late to save the damaged components if the faults are caused by water damage. Check with an auto electrician if the faults persist. 

A noise similar to water moving around in a half-full water bottle is often caused by water getting into your doors. 

Water entering the door frames is not actually uncommon, the seals on the outside are not designed to prevent all water ingress. Instead, the doors have drain holes to allow the water to simply drain away. 

If these drain holes become clogged, the water can build up, potentially leaking into the car, causing problems with electric windows and speakers, or causing the door itself to rust. 

Water leaks can be difficult to trace, but there are only a certain amount of entry points on most cars. 

Whilst there aren’t likely to be any specialist damp/leak experts for cars, any general mechanic should be able to investigate water leaks in your car. 

If possible, we’d suggest a garage that specialises in your make of car, as they are more likely to have come across the common causes on that specific model before. 

Split the cost of repairs into interest-free monthly repayments with 

The cost to fix water leaks can be anywhere from £50 to £2,000+, depending on the level of damage caused by the water before it is fixed. 

Some water leaks can be fixed simply by replacing a broken seal or rubber, some may even still be present but have simply become dislodged from their intended position. Both situations would be reasonably cheap to fix. 

If there has been rainwater leaking into the car for a while, costs could quickly rise if electrical systems have been damaged, or upholstery needs to be professionally cleaned or replaced. 

If you have a water leak and are wondering whether to bother getting it sorted, we would recommend doing so as soon as possible, purely to avoid hefty bills down the road. Water damage can be significant. 

 controls every electrical system in a car, and the module is sometimes mounted near potential water ingress points. 

The cost of repairing water damage to your car's ECU could easily run into the thousands, as a replacement often involves also replacing ignition key modules, immobiliser modules, door locks and more.

If water leaks are left unabated, mould is likely to develop, this combined with staining, carpets and seats can be damaged to the point of being uneconomical to repair. 

As they’re not a service item, replacement carpets and seats can be hard to come by, and take many hours to replace. 

, and whereas modern cars are protected from this by design (as well as their paint), water-logged carpets and upholstery can cause untimely corrosion to areas such as floor pans, bulkheads and roof panels. 

We’ve explained why it's critical to fix a water leak, and how to spot one, but how do you fix a water leak in your car? The answer generally depends on where the leak is from. 

Once located, assess the area from where the water is leaking, if a seal is obviously damaged or not properly secured, try to reattach or affix this. When investigating a leak, check for any loose bolts, screws or trim panels, as these could be preventing a seal where required. 

If the leak is not easily apparent, or you need to remove panels or components for better access, we’d advise seeking professional advice first. 

Whilst a short-term solution may not be perfect, it could help prevent further damage, as long as it doesn't become an insufficient long-term fix. 

Plastic bags or sheeting can be used to stop water ingress, or if the area of the leak is not known exactly, a car cover could be used to shield the affected area during a shower. Half covers are also available that just cover the roof and windows. 

We would not suggest using silicone sealant or glue as these can sometimes make the problem more difficult to fix permanently later on. 

, you can split the cost of car repairs at 4000+ expert repairers across the UK. Apply online before your visit to the garage in just a few clicks. 

Joseph Law

Bumper Content Writer

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