The engine is the heart and soul of any SUV. A problematic engine can bankrupt us through maintenance and repairs. European luxury SUVs are no exception. Luxury car brands can sometimes disappoint when it comes to engine maintenance. For example, Audi and BMW have made some very reliable engines. On the other hand, some of their engines may disappoint. Engine problems, such as deteriorating pipes and overheating, are some of the issues that can affect some of these problematic SUVs. On the other hand, oil leaks are among the glaring problems with some Mercedes-Benz models that many people ignore.

Identifying the type of engine can help us locate deeper problems. For example, Mercedes-Benz has built some reliable engines, while you may want to stay away from others. Websites such as Car Complaints, Consumer Reports, and NHTSA can offer us some insight into an SUV's reliability and even the problems associated with its engine. Let's check out some of the European luxury SUVs with the most unreliable engines.

RELATED: 5 Porsche Engines That Belong In A Junkyard (5 That’ll Run Forever)

10 2013 BMW X3

2013 BMW X3
BMW

For starters, the BMW N20 engine caused the company some concern, with recalls as a result of timing chain issues. Let's not forget that replacing a timing chain can create added expenses. The 2013 BMW X3 with its N20 engine has created headaches for some owners. Car Complaints notes complaints for the 2013 BMW X3 due to a broken timing chain.

The 2013 BMW X3 was given 1/5 for reliability by Consumer Reports. Trouble spots included the engine, which was also given a score of 1/5. Kelley Blue Book notes a medium risk of repair for the 2013 BMW X3. Engine diagnostics were one of the most common issues for service.

RELATED: 10 Most Reliable BMW Engines Ever Built

9 2004 Porsche Cayenne

Silver Porsche Cayenne SUV parked
Porsche

Some used first-gen Porsche Cayenne models years we wouldn't touch with a 10-foot pole. At the same time, some Porsche engines will run for a lifetime. However, some are not worth a second look. The 2003-2006 turbo 4.5-liter V8 engines came with troublesome plastic cooling pipes. Over time, the pipes deteriorated.

Repair Pal suggests that the main complaints included engine stalling or not starting and coolant leaks. Nine recalls were made. NHTSA recorded 100 complaints for the 2004 Porsche Cayenne. 17 of those complaints were for the engine, along with 12 complaints for engine cooling issues. Car Complaints cites the worst 2004 Porsche Cayenne problems as broken coolant lines, driveshaft problems, and engine not starting.

8 2008 BMW X5

2008 BMW X5
Via: Mecum Auctions

Some BMW engines will annihilate anything, while others belong in a junkyard. The N62 is one of the 'worst' engines. The N62 engine was used in certain BMW models between 2001 and 2010. The N62 engine faced numerous reliability issues, including oil leaks. One of those with the N62 engine is the 2008 BMW X5. The 4.8-liter V8 delivers 350 horsepower.

The 2008 BMW X5 was recalled sixteen times. Three of those times were for engine issues, such as problems with the PCV heater and engine cooling issues. NHTSA recorded 322 complaints for this model year. 121 of those complaints were for engine and engine cooling issues.

RELATED: 5 European V8s That'll Last You A Lifetime (5 That'll Destroy Your Savings)

7 2002 Land Rover Discovery 2

2002 LAND ROVER DISCOVERY II
Via: Mecum Auctions

The Land Rover's TD5 (Turbo Diesel) engine from 1998-2007 was not without problems. Head gasket problems are an issue. Overheating and coolant leaks are some of the symptoms. The Land Rover Defender TD5 is one of the used Land Rovers nobody wants to be associated with.

Land Rover Discovery 2 models suffered their own set of issues, such as problems with the head gaskets and cracked blocks. The 2002 Land Rover Discovery 2 was recalled four times, for issues including the possibility of fluid from the pump joint igniting. NHTSA records 51 complaints. 20 of those complaints related to engine and engine cooling.

6 2014 Audi Q5

2014 Audi Q5 SE TDi Quattro Automatic 2.0
Via: Wikimedia

Audi has excited us with some reliable engines. However, some are not as desirable. TecFlow suggests that the problems with the Audi TFSI engine include excessive oil consumption, and timing chain problems, among other things. The 2014 Audi offers the 2.0-liter TFSI engine.

Consumer Reports gives a score of 3/5 for reliability, with 1/5 for major engine issues. Car Complaints cites engine issues as the main complaint. The website suggests that the main problems are excessive oil consumption, the engine dying or not starting, and timing chain problems. Five recalls were made. Two related to issues with the coolant pump. NHTSA recorded 74 complaints. A third of those complaints related to the engine.

5 2011 BMW X6

Black 2011 BMW X6
Via Mecum Auctions

The 2011 BMW X6 is one of those BMWs that may cost more to maintain than to buy. In fact, the annual repair costs for a 2011 BMW X6 come out to about $1205, according to Repair Pal. Some expensive cars are worth the cost of maintenance. However, you may want to take a second look at some of the 2011 BMW X6's engine woes.

The 2011 BMW X6 was recalled thirteen times. One of those times was due to engine overheating. Another time was due to the possibility of engine stalling. Car Complaints suggests the severity rating for engine problems as severe. Engine overheating was among the main complaints, along with oil consumption.

4 2006 Mercedes-Benz ML350

2006 Mercedes-Benz standing still
via NetCarShow

The 2006 Mercedes-Benz ML350 is one of those Mercedes-Benz models you should never buy used. Mercedes-Benz launched the ML350 in 2002. In the infancy of its production, this SUV had its own teething problems. However, the 2006 model year was one of the worst.

Car Complaints cites engine problems as the main complaint. Repair Pal cites the main complaints as camshaft issues, electric problems, and even engine performance as among the main complaints. The 2006 Mercedes-Benz ML-Class was recalled three times. One of those times was for engine stalling.

3 2007 Mercedes-Benz GL450

2007 Mercedes-Benz GL 450
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The M273 engine is one of the Mercedes-Benz engines to stay away from. Timing chain issues causing engine problems and oil leaks are among some of the problems. An M272 and M273 engine class action was even filed because of defective gears causing problems.

One example is the 2007 Mercedes-Benz GL450. Engine stalling, oil consumption, and electrical issues are some of the reported problems. Repair Pal cites internal component failure causing rough shifting, oil leaks, and engine performance due to crankshaft issues as some of the main complaints. The 2007 GL-Class was recalled three times. One of those times was for engine stalling.

2 2017 Audi Q7

2017 Audi Q7
Via: Wikimedia

The 2017 Audi Q7 is powered by a 252 horsepower turbocharged 2.0-liter inline-four engine. Otherwise, you could choose a 333-horsepower supercharged 3.0-liter V6 engine. However, the 2017 Audi Q7 is one of those Audi that you should stay away from.

Consumer Reports rates the reliability of the 2017 Audi Q7 to be 1/5. The reliability of its engine is rated as 1/5. Car Complaints suggests that some of the worst problems for the 2017 Audi Q7 include "catastrophic engine failure", along with engine stalling. This website gives it a severity rating of really awful.

1 2015 Mercedes-Benz GLA

Brown 2015 Mercedes-Benz GLA-Class
Via Mercedes-Benz

The 2015 Mercedes-Benz GLA came with the 208-horsepower turbocharged 2.0-liter four-cylinder engine. The 2015 Mercedes-Benz GLA-Class was recalled four times. One of those times was for the possibility of engine stalling because of engine damage. Car Complaints suggests that the worst problems include the car dying while driving, unable to start the engine, and transmission failure.

Like their American counterparts, we have seen some very reliable European luxury SUVs. However, some luxury SUVs may disappoint. One of the key areas to check is any potential engine problems. Such problems can break the banks when it comes to maintenance and repairs. European luxury SUVs with unreliable engines are best avoided.