Buying a used BMW: what to consider, common problems, what to look for?

What to consider when buying a used BMW

The Bimmer is an excellent driving machine, thanks to its classic rear-wheel drive platform and strong engines. A new BMW costs a lot, so many buyers opt for used models; they are not very expensive and widely available.

What should you consider before buying a used BMW? Are the BMWs reliable? What are the common problems? The first thing to consider is the depreciation.

Depreciation: One issue with BMWs is that they depreciate a lot. For example,  a three-year old 3-Series BMW is priced around $30,000, while a 6-year old 3-Series averages around $17,000.

This means that a three-year old 3-Series will cost you nearly $4,000 per year in lost value alone. Considering this, opting for a 5-6 year old BMW  could be a better option from the financial point of view. It's not too difficult to find a 5-6 year old BMW in good condition.

Ownership costs: Repair, maintenance and insurance costs for BMW are higher than for an average car. With more expensive parts, premium gasoline, synthetic oil, high-end or run-flat tires and higher repair labor costs, expect to pay significantly more per year for a BMW than for a Honda or Toyota. Reliability: BMWs are well-engineered and solidly built, but they won't be as reliable as Japanese brands. Generally, BMW cars are rated 'average' or 'below average' for reliability.

It's pretty much given that a used BMW will need some repairs here and there.  One common issue causing problems with BMW and other European autos is the use of plastic instead of more durable materials. Plastic parts degrade with age.

Another issue is the large amount of complex electronics.

 Long service intervals designed to lure new car buyers don't help either. Turbocharged models are typically more troublesome.

Service and Repairs: If you are planning to buy a used BMW, It might be a good idea to find a local repair shop with good reputation that specializes in BMW.

 These German machines have a lot of specifics and not every garage may be able to handle the repairs.

Servicing at a dealership tends to be crazy expensive, so a local trusted BMW-specialized shop is a big plus. You might even consider using their services to pre-inspect the used car that you want to buy.

DIY is another option. If you like to get your hands dirty and you know what you are doing, you will save a lot of money.

Common problems:

The engine cooling system problems are fairly common including coolant leaks and failed water pumps. The cooling system issues must be addressed as soon as possible, as the overheating can cause serious engine damage.

The crankcase ventilation system (CCV) is another source of many problems. This thread explains the CCV issues in details. Vacuum leaks caused by cracked hoses, intake boots and CCV issues are also common.

Oil leaks often cause a smell of burnt oil under the hood. Repairing oil leaks on a high-mileage engine is a never ending story.

High pressure fuel pumps and fuel injectors fail quite often and they are expensive.

 The DISA valve replacement is another common repair. Of course, many of these issues will also trigger your Check Engine light. This forum, for example, describes many Check Engine issues in the E46.

Issues with the electronics are not uncommon too, especially given that there are so many electronic devices and control modules.

On the plus side, there are a lot of BMW enthusiasts who don't mind sharing the information, so you won't have troubles finding the DIY Youtube videos and forum threads.

What to look for when buying a used BMW:

We recommend to look for a model with a non-turbo engine, as it will be less troublesome and cheaper to keep on the road. The same goes for 4WD: if you don't need it, a rear-wheel drive model will be less expensive in potential repairs.

When checking a used BMW, test all the electronics thoroughly, including the remote, windows, power seats, seat heaters, audio system, Bluetooth, etc.

Electric folding side mirrors, windshield washer functions, power locks also need to be thoroughly tested, as they are common trouble spots.

Check the heater and air conditioner carefully. Watch out for a noisy blower motor. Make sure the blower motor works at all speeds. If there is a lack of heat from the vents at idle, but good heat when driving or revving the engine suspect air pockets in the cooling system which could potentially point to more serious problems.

Check for water damage and corrosion under the carpet, including in the trunk; water is the enemy of electronics. In newer cars, make sure the key fits well in the key holder.

 There are complaints about hairline cracks in the alloy rims causing air leaks; the cracks are very small and difficult to detect, so be suspicious if the tires are low on air.

Watch out for coolant leaks and coolant smell under the hood. Be suspicious if the coolant level is low or if it looks like the coolant was splashing out of the expansion reservoir like in this photo. Was the engine overheated? Overheated engines should be avoided.

Check carefully for oil leaks and watch out for a burnt oil smell under the hood. This 3-series in the photo below has a major oil leak, which is not a good sign.

Engines that have been overheated are more prone to have oil leaks because the seals and gaskets become hard and brittle after overheating.

In the N54 engine (335i, 535i), a long crank and rough idle when started cold usually indicate a failing high pressure fuel pump.

Check the tires, are they run-flat? Run-flat tires are very expensive to replace. Many owners opt for regular tires while adding a spare tire or a tire repair kit to the trunk.

During a test drive, watch out for rough shifts from the transmission and clunks from the drivetrain.

If the vehicle has a manual transmission, all gears should engage smoothly without grinding. If the clutch engages closer to the top of the clutch pedal travel, suspect a worn out clutch disc.

If it's 4WD vehicle, check if the 4WD system engages and disengages. It would help if you could actually test the 4WD system in slippery conditions.

Watch out for warning lights and messages. Any warning light must be thoroughly investigated before purchase.

When it comes to buying used BMW, the mechanical condition is much more important than the age or mileage. Avoid cars that were previously damaged in an accident or if the engine has been overheated. Check out the used car history report. Before signing the deal, have the car thoroughly inspected by a BMW-specialized mechanic.

BMW Tech tips:

If you want to keep your BMW longer, it will need more frequent regular maintenance than specified in the factory maintenance schedule.

Get familiar with common problems and ways to prevent them or at least learn to recognize telltale signs of problems earlier; there are many discussion about common issues on various BMW forums, see a few links below.

Any problem will cost less to repair if caught early. If your car starts overheating, or if you notice coolant leaks on your parking spot, have the car checked out as soon as you can. Overheating can cause serious problems with your engine. For the same reason, periodically check the coolant level and keep it topped up.

For an all-wheel drive model, it's important to keep the tires properly inflated. For some tire sizes, the pressure specs are different for the front and rear tires; check the tire placard located on the driver's door jamb for the correct pressure. Improper tire pressure can cause variety of issues in all-wheel drive models, including jolts when accelerating or coming to a stop.

Keep your BMW dry; spilled coffee or water leaking under the carpet or into the trunk can cause a lot of expensive problems with the electronics.

Resources
Owner's Manuals at BMW USA - download a pdf. owner’s manual
Search for Recalls at NHTSA
Bmwcca.org - BMW Car Club of America
Bimmerfest.com – forum with FAQ for each model