Replacing a Caterpillar 3126 – Useful information to help find the right replacement diesel engine
So you have a truck with a diesel engine in your truck and it broke down or is about to break down and you are looking for a replacement. This article has useful information that can help. If you’re looking for one, make sure you have the serial number and horsepower of your engine.
Some motors may swap for others, but it’s important to note how many pins are on the computer. Older computers will have 40 pins while newer engines will have 70 pins. They will interchange 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 pin will be an older motor
- 70 pin will be a newer motor
Serial numbers:
- 9SZxxxx 8YLxxxxx 7ASxxxxx = 70 PIN computer
- 1WM = 40 Computer PIN. Dual air induction on the right side of the engine
- HEP = 70 Computer PIN. Air intake on the left side of the engine, a tube faces forward
- 7AS – Can be used instead of a HEP computer – 70 PIN
- 6RW = 70-pin computer
If you’re having trouble finding a good used 3126 with low miles, you can use a Caterpillar C7. It will have 70 pins so make sure your computer also has 70 pins or you will need to purchase an adapter wiring harness.
You can put the same engine model with a different number of pins with the addition of the following harnesses.
40-pin computer to 70-pin harness = Mawk Industries Harness, 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’re buying it from knows the computer miles. You can find out how many miles the engine has by connecting a professional link. All quality heavy truck salvage yards will have one of these.
