• Although a common tractor engine, the John Deere 5.9 liter engine can be used in other machinery.Tractor image by Arne Bramsen from Fotolia.com
  
  John Deere makes two different 5.9 liter engines. Although the cylinders have similar specifications, there are a number of notable differences in the two engines. Both engines, introduced in 1966, are 6-cylinder engines that use different types of fuel. The difference in fuel accounts for differences in specifications between the two otherwise very similar engines.
  
  

Fuel Types

• The most notable difference between the two John Deere 5.9 liter engines is their fuel. One engine uses gasoline, the other runs on liquefied petroleum, or LP, gas. Propane is, according to the U.S. Department of Energy, cleaner burning than gasoline. Because it combusts in a gas form instead of a liquid, it starts in very cold weather more reliably than natural gas.
  
  

Cylinders and Displacement

• As a 5.9 liter engine, the American measure of engine displacement is 362 cubic inches. Each of the engine's 6 cylinders has a bore and stroke of 4.25 inches. The compression ratio between the two engines is different. The gasoline-powered engine runs at 7.5:1 compression while the LP engine runs at 9:1. Both engines are rated at up to 2,200 revolutions per minute (RPM). The cylinder firing order for both engines is 1-5-3-6-2-4.
  
  

Oil, Coolant and Electrical

• The engines have identical requirements and specifications for oil and coolant. Both engines are liquid cooled and require 24 quarts, or 22.7 liters, of coolant. Both engines also require 8 quarts of oil as the lubricant. Both engines require 12 volts for the starter and ignition.