Detroit Series 60: Life Expectancy and Common Problems

The Detroit 60 is a heavy-duty diesel engine by Detroit Diesel. It is their most successful diesel engine, selling over 1.2 million units. The Detroit Series 60 was produced between 1987 and 2011 and can be gotten with either 11.1-, 12.7- or 14.0-liter displacements.

This article has two focus areas. First, it discusses the life expectancy of the Detroit Series 60 engine. Then, we assess some of the series 60's common problems. Before both, we set the foundation by running through some specifications and features of the Detroit Series 60.

Detroit Series 60: Specifications and features

The Detroit Series 60 is an inline four-stroke diesel engine. It was the first heavy-duty engine with an electrical control system in on-highway engines. The Detroit Series 60 also had a unique camshaft arrangement. It used an overhead camshaft, which operated the intake and exhaust valves as well as the fuel injector plunger.

The Detroit Series 60 was launched with two different engine displacements, 11.1L (Liter) and 12.7L. Yet, in 2001, Detroit Diesel launched a 14L displacement edition. The 11L variant was discontinued in 1997, and the 12.7L version was produced until 2007. Only the 14L version was produced from then until the Series 60's discontinuation in 2011 in favor of the DD15 engine.

The Detroit Series 60 engine is large, and it gets larger with the displacement. Larger displacement engines move more air and fuel, producing more power, faster acceleration, and increased towing capacity.

The 14L Series 60 is a bit larger than the others. The cylinder bore and stroke on the 14L are 5.24 and 6.62 inches, respectively. The 12.7L and 11.1L share the same cylinder bore at 5.12 inches. However, the 11.1L has a smaller 5.47-inch stroke than the 12.7L's 6.30-inch stroke.

The rated horsepower (hp) of the Series 60 is quite impressive. The 11.1L has a 250 to 350 hp at 1800 Revolutions Per Minute (rpm). For the 12.7L, the rated hp is between 380 and 455 hp at 1800 rpm. The highest rated hp is the 14L and stands between 425 and 515 hp at 1800 rpm. The rated torque of these machines is a similar story, with the higher displacement producing more.

One of the key innovations of the Series 60 was its use of electronic injection control. The Series 60 engines used the Detroit Diesel Electronic Control (DDEC) fuel injection system. The Series 60 engines have Electronic Unit Injector (EUI) fuel injectors, which are operated by the engine control module (ECM). With the aid of sensors, the ECM controls injection timing, pump pressure, and pulse width. DDEC can also shut down the engine in case of an emergency.

Detroit Diesel updated and improved DDEC several times. The versions are DDECI, DDECII, DDECIII and DDECIV. Each version came with several improvements, including upgrades in emission management and diagnostic capabilities.

Life Expectancy of Detroit Series 60

Besides the new technology that came with the Series 60 engines, the longevity of these engines was also compelling. At launch, Detroit Diesel's recommendation for a first overhaul or major maintenance was after 500,000 miles of operation. An overhaul will involve disassembling the engine and repairing and replacing some components to keep it running optimally. Also, subsequent rebuilds needed to be done after every 500,000 miles of use.

The significant overhaul recommendation was a major boon for continued performance and longevity. Yet, Detroit further increased the recommended overhaul recommendation interval to 750,000 miles. So, on paper, the Detroit Series 60 engines were solid, durable engines with generous life expectancy.

In reality, the Detroit Series 60 engines have a good life expectancy reputation. Life expectancy will vary based on the application, operating conditions, maintenance, and usage. However, based on feedback, these engines will last between 750,000 and 1,000,000 miles with proper maintenance. In some cases, they can last even longer before requiring a major overhaul. However, we recommend carrying out major overhauls in line with Detroit Diesel's recommendations.

Common Problems of Detroit Series 60

The Detroit Series 60 engines have a long and well-regarded history and reputation as reliable and powerful engines. Also, they have solid life expectancy and durability. Yet, in that history also comes some problems. This section discusses some of the common problems of the Detroit Series 60 engine.

1) Wrist Pin Issues

Problems with the wrist pin of the Detroit Diesel Series 60 are well documented. The models most affected by the issue were those produced pre-2002. While it was rare, it occurred enough times to be considered a problem with some of these engines.

The wrist pin connects the engine's piston to the connecting rod. This connection allows the smooth movement of the piston up and down the cylinder bore. Critically, the wrist pin must be durable to bear the load of the piston and significant stress during heavy engine operation. Wrist pin failure can damage the engine.

Unfortunately, in some Series 60 engines, a defect in the wrist pins caused the separation of the piston pin and crown. In some instances, the connecting rod would also separate. Loose components from the separation sometimes damage the engine block. In some cases, this situation led to complete engine failure.

2) Exhaust Gas Recirculation Problems

Exhaust Gas Recirculation (EGR) is a component manufacturers use to control diesel engine emissions. They reduce the number of Nitrous oxide (NOx) diesel engines produce significantly. Besides that, EGR can improve fuel economy by bringing down combustion temperature.

Detroit Diesel introduced EGRs into the Series 60 engines in 2002. With the addition of this technology came some problems. However, the main issue was with the EGR cooler. The EGR cooler is a heat exchanger, and it cools exhaust gas before it is recirculated back to the engine. It uses coolant to cool the gas.

It was not unusual for Series 60 engines with EGRs to leak coolant. Coolant leaks will cause overheating for the engine. Overheating can be disastrous for the engine. Some symptoms of coolant leak from the EGR's cooler beside the engine overheating include white smoke and quick coolant loss.

3) Bearing Problem

The Detroit Diesel designed the Series 60 to idle at low rpm. The low idle speeds caused problems of their own. Basically, the oil pump did not receive enough power to function effectively when the engine idled. Without enough oil flow, the bearings do not get adequately lubricated. Poor bearing lubrication can lead to overheating and the engine seizing.

The bearing problems are found in the Series 60's released before 1997. So, it does not include the 14L at all. The bearing problems became less of an issue with post-1997 12.7L and 14L engines because Detroit Diesel increased their idle speed to ensure enough oil pump pressure at low rpm.

4) Exhaust Manifold Cracks   

A potential issue with Series 60 engines is a cracked exhaust manifold. The exhaust manifold is part of the exhaust. Its job is to collect exhaust from the cylinder and let it out through the exhaust pipe. A fairly common issue with Series 60 engines was the appearance of cracks on the exhaust manifold.

Symptoms include power loss, increased engine noise, exhaust smells from the engine bay, and exhaust backpressure. Small cracks in the Series 60 may not quickly lead to these symptoms. While the exhaust manifold crack was not a big problem, it was important to address it so it did not lead to more serious problems. A cracked exhaust manifold in the Series 60 could burn exhaust valves, cause catalytic converter failure, and cause EGR problems.

5) Poor Fuel Economy

Nobody wishes for a machine that is fuel-inefficient. In fact, poor fuel economy is one reason to avoid a particular machine. With the introduction of the 14L series 40 engine came complaints about fuel economy. The 14L is bigger than its predecessors. It has more displacement, horsepower, and torque than its smaller siblings. However, it also increased fuel usage.

6) Emission Systems Problem In 14L

The most recently produced models of the Series 60 are the 14L models. Due to their recency, they have the most modern emission systems. Due to tougher emissions requirements by governments, many diesel engine producers had to develop new technologies to further reduce emissions. Some of the most recently produced 14L Series 60 engines have Diesel Particulate Filters (DPF) and Diesel Oxidation Catalyst (DOC), amongst other new emission components.

Reducing emissions is fine. However, these new technologies are complex and come with unique issues when managing them. Some of the 14L Series 60 did not escape these troubles. The increased complexity of the engines due to these very intricate emissions control devices created more hassle for their operators.

Conclusion

Detroit Series 60 are solid, well-crafted engines that were ahead of their time due to some unique innovations, including DDEC. Our focus in this article was the life expectancy and common problems of the Series 60 engine. For life expectancy, the Series 60 is a really durable engine. Detroit Diesel Series 60 engines may not need a major overhaul until 750,000 miles. Reports show that the engine holds up on that end.

The Detroit series has a few known problems. Pre-2002 models are known to have wrist pin issues, while post-2002 variants may suffer EGR-related difficulties. Also, some pre-1997 Series 60 may suffer from bearing problems. 14L Series 60 is noted for its poorer fuel economy and greater emissions problems. All Series 60 owners should be mindful of exhaust manifold cracks.