{"id":5315,"date":"2021-03-30T14:38:54","date_gmt":"2021-03-30T14:38:54","guid":{"rendered":"https:\/\/www.xtremediesel.com\/blog\/?p=5315"},"modified":"2025-02-18T03:21:15","modified_gmt":"2025-02-18T03:21:15","slug":"1989-1993-dodge-5-9l-diesel-buyers-guide","status":"publish","type":"post","link":"https:\/\/www.xtremediesel.com\/blog\/2021\/03\/30\/1989-1993-dodge-5-9l-diesel-buyers-guide\/","title":{"rendered":"1989-1993 Dodge D\/W with 5.9L Cummins Buyer’s Guide"},"content":{"rendered":"\n
\"Dodge<\/figure>\n\n\n\n

History\/General Info<\/h2>\n\n\n\n

If you are familiar with diesel trucks, you have probably heard of the first-gen Dodge. When Dodge introduced the 5.9L 12-Valve \u20186BT\u2019<\/a><\/mark> engine it helped create a new standard for OEM diesel performance and completely revitalized their truck lineup. The Dodge AD platform originally debuted in 1972 and was used all the way up to 1993. Beginning in 1989, Dodge began to offer a 5.9-Liter Inline 6 Cylinder Cummins Turbodiesel in their 3\/4 and 1-ton Dodge pickups. The 5.9L Cummins quickly became a popular alternative to Dodge’s V-8 gas engines, as the diesel offered nearly double the torque at low engine speeds. The 5.9 diesel had some unique features never seen on a diesel pickup truck before, including a turbocharger and direct fuel injection. It was revolutionary for the time and had a huge impact on drivability and towing capability.<\/p>\n\n\n\n

5.9L Turbocharger<\/h2>\n\n\n\n

A turbocharger uses exhaust gas and converts this energy into compressed air. This condensed air is forced into the engine which helps translate into more power, improved fuel economy, and better towing performance, especially at higher altitudes. The turbodiesel engine vaulted Dodge\u2019s aging D250\/350 & W250\/350 (Ram) platforms to a best-in-class torque rating of 400 lb-ft. General Motors & Ford were still utilizing naturally aspirated diesel engines with GM’s Detroit Diesel 6.2 offering 240 lb-ft of torque, while Ford\u2019s International Harvester 7.3 IDI was rated at 338 lb-ft of torque.<\/p>\n\n\n\n

Now 160 horsepower and 400 lb-ft of torque might not seem that impressive by today\u2019s standards, especially when you compare it to many of the later-model diesel offerings. Fortunately, you can crank up the horsepower and torque numbers on the 6BT relatively easily. Aftermarket upgrades are available that drastically raise the factory ratings and really help wake it up. Best of all, since the 6BT was originally designed for commercial and agricultural applications, the robust design is more than capable of handling the bump in power without needing to completely tear it down.<\/p>\n\n\n\n

1989-1991 Model Years<\/h2>\n\n\n\n

Like most full-size pickups Ram trucks were available in three series, which designate payload: 150-series (1\/2-ton), 250-series (3\/4-ton), and 350-series (1-ton). Two-wheel drive Rams got a \u201cD\u201d prefix, while four-wheel drive Rams were designated with a \u201cW\u201d.<\/p>\n\n\n\n

The base engine in 1989 was a 3.9-liter V6, with optional 5.2 and 5.9-liter gas V8s available, but the big milestone was the arrival of the 5.9 diesel in the 3\/4 and 1-ton trucks. The diesel engine was initially only available with a regular cab and a long bed. The club cab (extended cab) debuted with the diesel engine on the D250\/W250 in 1990 and on the D350\/W350 in 1992. <\/p>\n\n\n\n

1991.5-1993 Model Upgrades<\/h2>\n\n\n\n

During the 1991 model year, the biggest highlight was when Dodge added an air-to-air intercooler to the diesel trucks. The hot compressed air that exited the turbocharger now traveled through an intercooler and was cooled down before entering the engine. A cooler and denser air charge helps to produce a more efficient combustion process and typically results in lower EGTs, improved fuel economy, and more power. Also in 1991, the automatic transmission was upgraded from the 3-speed A727 Torqueflite to the 4-speed A518 (46RH), which aided in improved fuel economy. These additions make the 1991.5-1993 model years slightly more desirable than 1989-1991 trucks for many buyers.<\/p>\n\n\n\n

5.9L Killer Dowel Pin (KDP)<\/h2>\n\n\n\n
\"5.9<\/figure>\n\n\n\n

Although many consider the 5.9L Cummins diesel engine to be one of the most reliable engines ever manufactured, it is not without its faults. One popular issue to be aware of is the Killer Dowel Pin or KDP. The term refers to a dowel pin failure inside any 1989-2002 12-valve or 24-valve 5.9 engine’s timing gear housing. This problem has the potential to “kill” an engine sometimes causing damage so severe that it cannot be repaired.<\/p>\n\n\n\n

The 6BT features a steel pin that is pressed into the block and aligns the aluminum timing gear housing to the engine. It is positioned above the cam gear and next to the injection pump gear. From the factory, the pin is not secured and over time due to engine vibration and other factors, the dowel can become dislodged from its bore. If the pin comes out it can possibly work its way down without doing any harm or, if you are not so lucky, all sorts of damage can ensue.<\/p>\n\n\n\n

There are plenty of kits available for this issue and are relatively inexpensive. The most common fix involves bolting on a teardrop-shaped steel retainer that secures the pin in its bore. This retainer prevents the pin from backing out and falling into the engine. Installing a KDP kit is cheap insurance.<\/p>\n\n\n\n

What To Look For When Purchasing<\/h2>\n\n\n\n

Like any older pickup truck, rust can be common. This is even more prevalent if you live in an area that gets snow, where salt and brine solutions are used on the roads during the winter. Check the bottom sides of the bed, the cab corners, rocker panels, and the floor for metal that might need replacing. Water getting through the vent windows or worn-out weather-stripping can also lead to rust in the doors.<\/p>\n\n\n\n

Trucks with higher mileage or hard miles will most likely need to have the suspension components gone thru. These trucks utilize kingpins that tend to wear out over time. The automatic transmissions were not particularly the stoutest and might need to be rebuilt or upgraded. This is especially the case if you have plans to raise the power levels of the 6BT Cummins. Finally, as in many older vehicles, electrical gremlins can be present or begin to appear over time.<\/p>\n\n\n\n

Pros\/Cons<\/h2>\n\n\n\n

Pros<\/strong><\/p>\n\n\n\n