So you have a truck with a diesel engine in your truck and it just went wrong or you are about to go wrong and you are looking for a replacement. This article has useful information that can help. If you are looking for one, make sure you have the serial number and horsepower of your engine.
Some motors can swap out for others, but it’s important to consider how many pins are on the computer. Older computers will have 40 pins, while newer engines will have 70 pins. They will be interchanged, but you will need an adapter wiring harness to make it work. Below is a list of serial numbers that will let you know how many pins are on the computer.
Number of pins on your computer:
- 40 pins will be an older motor
- 70 pins will be a newer motor
Serial numbers:
- 9SZxxxx 8YLxxxxx 7ASxxxxx = 70 PIN computer
- 1WM = 40 PIN computer. Double air induction on the right side of the engine
- HEP = 70 PIN Computer. Air inlet on the left side of the engine, one tube faces forward
- 7AS – Can be used in place of a HEP computer – 70 PIN
- 6RW = 70 PIN computer
If you are having trouble finding a used 3126 in good condition with low miles, you can use a Caterpillar C7. It will have 70 pins so make sure your computer has 70 pins too or you will have to buy an adapter wiring harness.
You can put the same motor model with a different number of pins with the addition of the following harnesses.
40-pin computer to 70-pin harness = Harness from Mawk Industries, phone number 602-909-1961
70-pin computer to 40-pin harness = Caterpillar part number 133-8109
Your best value will be finding a used diesel engine, just make sure the place you buy it knows the miles off the computer. You can find out how many miles are on the engine by connecting a professional link. Every quality heavy duty truck salvage yard will have one of these.