Mercedes Diesels to Avoid: A Comprehensive Guide
Mercedes-Benz has a long and storied history of producing diesel engines, with some of the most iconic and reliable powertrains ever made. However, not all Mercedes diesels are created equal. Some models are known for their longevity and trouble-free operation, while others have been plagued with problems.
If you're considering buying a used Mercedes diesel, it's important to do your research and avoid the models that are known for being problematic. Here are some of the Mercedes diesels to avoid:
1. OM601/602/603/604/605/606 Engines (1985-2002)
These inline-6 diesel engines were used in a variety of Mercedes models, including the W123, W124, W126, and W140. They're known for being over-engineered and durable, but they can also be expensive to maintain and repair.
Common problems with these engines include head gasket failure, oil leaks, and turbocharger failure. The OM606 is generally considered to be the most reliable of the bunch, but it's still not without its problems.
2. OM642/646/647/648 Engines (1997-2016)
These V6 diesel engines were used in a variety of Mercedes models, including the W211, W212, W204, and W205. They're known for being smooth and powerful, but they can also be expensive to maintain and repair.
Common problems with these engines include injector failure, turbocharger failure, and EGR valve problems. The OM642 is generally considered to be the most reliable of the bunch, but it's still not without its problems.
3. OM651 Engine (2008-2016)
This inline-4 diesel engine was used in a variety of Mercedes models, including the W204, W205, and W212. It's known for being fuel-efficient and powerful, but it can also be expensive to maintain and repair.
Common problems with this engine include injector failure, turbocharger failure, and EGR valve problems. The OM651 is generally considered to be more reliable than the OM642 and OM646, but it's still not without its problems.
4. OM628/629 Engines (1998-2016)
These inline-5 diesel engines were used in a variety of Mercedes models, including the W163, W164, and W166. They're known for being powerful and torquey, but they can also be expensive to maintain and repair.
Common problems with these engines include injector failure, turbocharger failure, and EGR valve problems. The OM628 is generally considered to be more reliable than the OM629, but they're both still not without their problems.
5. OM611/612/613 Engines (2001-2010)
These inline-4 diesel engines were used in a variety of Mercedes models, including the W203, W204, and W211. They're known for being fuel-efficient and reliable, but they can also be expensive to maintain and repair.
Common problems with these engines include injector failure, turbocharger failure, and EGR valve problems. The OM612 is generally considered to be the most reliable of the bunch, but they're all still not without their problems.
Conclusion
If you're considering buying a used Mercedes diesel, it's important to do your research and avoid the models that are known for being problematic. By following the advice in this guide, you can help ensure that you get a reliable and trouble-free Mercedes diesel.
