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Our Top 5: Engines that can survive with next to no maintenance.

This is a follow-up to a recent post of ours, where we discussed five car & truck engines that require very religious maintenance in order to survive. This time, we’re looking in the opposite direction with our list of the five toughest engines that seem to keep on ticking, no matter what – even when a questionable oil change history is involved.

You’ll notice that compared to our other list, most of the engines on this list are older powerplants. There’s a reason for that, and it brings up an interesting point: While engines have become more and more reliable over time, we reached a bit of a “reliability peak” around 2010. Now as consumers (and the government) seek better and better fuel economy without being willing to give up horsepower, car manufacturers are squeezing more and more power out of smaller engines. This has necessitated technologies like variable valve timing; direct injection; and turbocharging; among others. Today’s engines are incredibly complex, and regular maintenance (like oil changes) is starting to become much more important again.

General Motors 4.8L/5.3L/6.0L LS V8, 1999-2007

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Applications (Partial List):
Chevrolet Silverado/GMC Sierra, 1999 – 2007
Chevrolet Tahoe/GMC Yukon, 2000 – 2006
Chevrolet Suburban/GMC Yukon XL, 2000 – 2006
Chevrolet Express/GMC Savana, 2003-2006
Chevrolet Avalanche, 2002 – 2007

The introduction of the LS-series engines in the late nineties marked the first major update of the Chevrolet small-block V8 engine in decades. The redesign was a success, resulting in an engine that made more power; achieved better fuel economy; and ran very smoothly while still maintaining a very simple engine design. Many of the issues that plagued earlier GM V8s (such as leaks) were eliminated, and the engine was made stronger.

These engines have proven very reliable and have become very popular for engine swaps into other vehicles because of their compact dimensions and simplicity. The LS engines have also earned a reputation as the cheapest way to make big horsepower, because of how plentiful these engines are and how well the stout blocks hold up under extreme pressure. It’s not uncommon for a weekend racer to take a completely stock junkyard 5.3L V8 with 300,000 km; install a supercharger or turbocharger setup; and make a fairly reliable 600-700 horsepower.

In their intended applications (GM trucks and SUVs) we see these engines last a very long time, even when they are very poorly maintained. Newer versions of the LS V8 introduced in 2007 are very good too, but not as “bullet proof” as their older siblings. The 2007+ engines can be prone to oil consumption, and experience problems with their Active Fuel Management (cylinder deactivation) systems.

AMC/Jeep 4.0L Inline Six

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Applications:
Jeep Comanche, 1987 – 1992
Jeep Cherokee, 1987 – 2001
Jeep YJ, 1991 – 1995
Jeep Grand Cherokee, 1993 – 2004
Jeep TJ, 1997 – 2006

Introduced in 1987 but loosely based on AMC engines that were much older, the Jeep 4.0L inline six cylinder engine was an absolute tank. With an inline configuration (vs the more traditional V6) and camshaft-in-block valvetrain, the design was super simple. Simplicity, as we often see in the automotive world, can be a major contributor to reliability. The engine also proved to be very robust, and produced lots of torque at low RPM – perfect for the off road vehicles that it powered.

The 4.0L engine also made very respectable horsepower for its day; about 25 hp more than similarly-sized engines from GM, Ford and Nissan at the time. The only strike against these engines was that – like many older engines – they were known for leaking oil; to the point where some mechanics joked, “If it’s not leaking, it’s not working right”. However, if you kept the oil topped up (and sometimes, even if you didn’t), the 4.0L inline six seemed to last forever with very little maintenance.

Used for an astounding 20 years, the 4.0L was finally retired in 2006 in favor of newer, cleaner and more fuel-efficient alternatives like Chrysler’s 3.8L minivan engine. (Which unfortunately proved to be much less reliable.)

Dodge/Ram 5.9L & 6.7L Cummins Diesel

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Automotive Applications:
Dodge (Ram) Trucks, 1989 – Present

It has been said that if it wasn’t for their business partnership with Cummins, Dodge wouldn’t have sold half as many 2500 and 3500-series trucks as they have; and most Ram salespeople agree! These engines have earned such a reputation that many buyers choose a Dodge truck only because it has the Cummins powerplant under the hood.

Using a super simple inline-six and cam-in-block configuration like our Jeep 4.0L above (and like many larger Cummins engines used in heavy trucks), the Cummins diesel is definitely the easiest light duty diesel engine to service. First introduced in 1989, the now-legendary 5.9L “12 Valve” Cummins engine powered Dodge trucks until 1998. After that it was replaced with several 5.9L 24 valve versions, and then in 2007 the displacement was increased to 6.7 litres.

We regularly see Cummins-powered Dodge trucks reach very high mileage levels, sometimes with a not-so-great maintenance history. Several years ago we repaired a very poorly-maintained 5.9L Cummins with 276,000 km that looked remarkable inside; with very little wear on its cylinders and bearings. These engines can reach a million kilometers with diligent maintenance, and my list of awesome customers includes a couple Dodge owners who are getting close: one with 850,000 km and one with 986,000 km.

Volkswagen 1.9L ALH TDI Diesel

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Applications:
Volkswagen Jetta, 1999 – 2005
Volkswagen Golf, 1998-2006
Volkswagen New Beetle, 1998 – 2005

While Volkswagen has produced many very good diesel engines over the years, the “ALH” engine used between 1998 and 2006 is regarded as one of the best. These engines were only used in cars, with 1.9 litres litres of displacement over 4 cylinders; direct injected and turbocharged.

These engines not only became known for their outstanding reliability, but also for the amazing fuel economy that they could achieve. Around 2005 the ALH engine was replaced with the Pumpe Düse engines that used camshaft-driven fuel injectors, and proved to be less reliable. Later still in 2008, the TDI engine was updated with a common rail fuel system, and it is these newer engines that became the subject of the Volkswagen emissions cheating scandal.

It’s not uncommon to see diesel-powered Volkswagens still on the road with 500,000 km on their odometer. We have disassembled and inspected various 1.9L ALH engines with between 300,000 and 500,000 km on them, and were very impressed with how little wear or damage we found inside them. Some of these engines were not very well maintained, which speaks to their durability. To date, the highest mileage ALH TDI engine we’ve had through our shop was underneath the hood of a 2004 Jetta with 720,000 km on it!

General Motors 3.8L “3800 Series 2” V6

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Applications:
Dozens of GM models from 1996 – 2005 including Chevrolet Impala, Lumina and Monte Carlo; Pontiac Bonneville and Grand Prix; Buick LeSabre, Park Avenue and Regal; Oldsmobile Intrique; and many others.

Introduced in 1995, the “3800 Series 2” was a 3.8L V6 that replaced the well-regarded “Series 1” engines used since 1991. These engines became known for their power; smoothness and great fuel economy for the time. They could also take a beating, either in the form of hard driving; poor maintenance; or both!

The 3800 V6 was offered in the “L36” naturally aspirated version, or an “L67” supercharged version that made up to 240 horsepower; a lot for an engine of this size in the late nineties. These engines could also deliver this power reliably and without major issues for 400,000 km or more. Because of their dependability; low maintenance costs; and engine block strength, the 3800 became a popular choice for custom high-performance and racing usage.

In 2004 the Series 2 3800 was replaced with the “Series 3” engine, also a very reliable performer. This engine was finally discontinued in 2009.

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