10 Engines Mechanics Warn You Never to Buy | Common Car Problems

The journalists note that the assumption that “there are no bad engines” anymore is demonstrably false. There’s a perception that manufacturers have accumulated enough experience to identify and avoid problematic solutions. However, reliability statistics, such as those from JD Power and similar organizations, show that the defect rate per vehicle has increased over the past 5-7 years, even during the early stages of ownership. German TUV inspection data also reveals a higher failure rate for relatively new vehicles compared to those inspected a decade ago. This suggests a rise in engines with flawed engineering, exacerbated by extended oil change intervals, lower viscosity oils, and other contributing factors.

Despite these trends, German journalists have pinpointed specific engines that mechanics consistently flag as having chronic, widespread issues.

The 1.2 PureTech engine from Stellantis, in its wet-belt version, found in numerous Stellantis and Toyota models, tops the list of engines to avoid. The primary concern is the wet timing belt, manufactured by Continental, which degrades due to the chemical composition of the engine oil it’s immersed in. This degradation is accelerated by gasoline contamination or oil breakdown, causing the belt to disintegrate. Fibers from the belt then contaminate the oil pump, restricting oil flow and potentially leading to engine failure.

The belt’s deterioration is expedited by using oil of the same viscosity as recommended but from manufacturers other than the original equipment supplier, where slight chemical composition differences can exist. Mixing different oil types, such as adding a cheaper oil to a premium one, further accelerates the process.

Even with strict adherence to recommended oil specifications, the belt is prone to failure. The initial “lifetime” recommendation for the belt should be disregarded, with replacement occurring at a maximum of 70,000 km or every 3 years – and potentially sooner. Mechanics in Germany caution that the complexity of access makes this repair particularly expensive, potentially rendering some compact models uneconomical to repair.

The Ford 1.0/1.5 EcoBoost and 2.0 EcoBlue engines share the same timing belt issue, exhibiting identical symptoms – belt disintegration from oil and fuel contamination, accelerated by infrequent oil changes or short trips that fail to adequately warm the engine and evaporate fuel from the oil. This ultimately leads to oil pump blockage and potential engine failure.

These engines also feature a second belt at the oil pump, constructed from a similar material and susceptible to the same problems. Both Stellantis and Ford have since transitioned to timing chains to address these issues, but the oil pump belt remains vulnerable. A timing belt replacement on a Ford can cost up to 2,500 euros in Germany, a significant expense considering the recommended replacement interval of 70-80,000 km.

The Ford 2.0 EcoBoost engine, with four cylinders, experiences a different problem: frequent block cracking, particularly in the Ford Kuga. A sudden loss of coolant is a key indicator of this issue, rendering the engine irreparable – requiring a complete block replacement.

Land Rover’s 2.0-liter engines also made the list, alongside other issues within the brand. The 2.0-liter gasoline engines suffer from block cracking similar to the Ford Kuga. Older models experience problems with the 2.7-liter and 3.0-liter diesel V6 engines, co-developed with PSA and Ford. Timing belt replacement is required more frequently than initially recommended, and on Land Rover models with a body-on-frame construction, the body must be detached from the frame and the engine decoupled from the transmission to perform the replacement, according to official instructions. The newer 2.0-liter Ingenium engines are less problematic regarding timing, but often experience critical bearing failures and subsequent engine seizure.

BMW’s 2.0-liter diesel and gasoline engines, produced from 2007 to 2014, are identified as a large group of engines prone to maintenance issues. The timing chain was reportedly too tiny and lacked sufficient strength, leading to premature stretching and a cascade of related problems. Affected engines include the N47, B47, N20, B20, B48, and B38. A rattling sound upon startup, initially brief but progressively worsening, is a symptom of these issues. The chain’s rear location necessitates transmission decoupling for replacement, increasing labor costs. However, mechanics note that proactive chain monitoring and timely replacement can ensure longevity and a pleasant driving experience, allowing some to capitalize on others’ avoidance of these engines.

The 1.4-liter engine from Opel, particularly paired with the M32 transmission (produced between 2004 and 2012), is considered highly problematic. The transmission’s fragile construction warrants avoiding all vehicles equipped with it. Mechanics caution that the same transmission was also used in Alfa Romeo 159, Spider, and Mito, Fiat Punto, Chevrolet Cruze, Saab 9-3 and 9-5, and Lancia Delta.

The Mercedes V8 4.6-liter engine is a surprising inclusion, but mechanics advise against it. Designated M278, versions produced between 2010 and 2015 are commonly found in models with the 500 designation. The engine’s issue stems from the special Silitec coating inside the cylinders, which lasts only 150,000-200,000 km. Once the coating wears away, increased friction between the piston and cylinder leads to rough running and eventual failure. Mercedes acknowledged the problem and switched to a different coating starting in 2015.

The VW TDI biturbo engine in the VW T5/T6 has proven exceptionally problematic. Designated CFCA, CXEB, or CXEC, these engines often exhibit excessive oil consumption, turbocharger issues, and are primarily attributed to a poorly designed EGR valve. Coolant loss is also common. Shortening maintenance intervals to a maximum of 15,000 km and continuous component checks are recommended for preventative repairs.

The VW EA111 engines, 1.2-liter and 1.4-liter, particularly from the early production periods, were notorious for timing chain tensioner problems. Turbine lines were another vulnerability, and versions with both a mechanical compressor and turbocharger often suffer from piston ring failure due to thermal stress. Shortening the service interval, checking the injectors, and ensuring fuel quality are crucial preventative measures.

Finally, with Nissan, mechanics pointed to a problematic transmission rather than an engine – specifically, Nissan’s CVT transmission, manufactured by Jatco. It’s poorly designed with insufficient cooling for intensive use, leading to a high failure rate and irreparable repairs due to its construction.

German journalists therefore recommend avoiding these engines, whether currently in production or found in used vehicles. Those already owning such an engine are advised to be aware of the vulnerabilities and implement preventative maintenance to avoid costly repairs.