We have 855 Cummins parts in stock and ready to ship to you. We offer low prices and a full one year warranty on all new items. Here you can find 855 Cummins specs, troubleshooting guidelines, and answers to common questions.

The classic 855 Cummins engine was used in a variety of uses, including older Mac trucks and much more. Finding parts for older engines can be hard, but we make it easy. We offer manufacturer direct prices on Cummins 855 parts and allow you to buy at prices that are much lower than other providers. Plus, we group all of the engine parts by engine model, making the buying process a little easier. 

We are also proud to offer Cummins NT 855 parts for sale, at low prices and also completely covered by our industry leading warranty. No matter if you are looking to fix a truck, train, or any other application, we are here for you.

We get all of our orders out for shipping within one business day and can get 855 Cummins engine parts delivered anywhere in the country, even as quickly as next day, sometimes less than 24 hours after ordering. Try us today. Contact our friendly associates for help finding the Cummins engine parts you need. Simply select your engine above to get started, or scroll down for more information.

The Cummins NT 855 and NH 855 use slightly different parts in some areas of the engine. For this reason, it is very important to correctly identify your engine. To do so, check the data plate on the mounting flange of the gearcase. A model number would be similar to NTA-855-C360. The first section identifies the actual engine, the C indicates it is for construction and the 360 is the horsepower. Other letters used include G for generators, P for power units, M for marine units, L for locomotive units and R for railcar applications.

What type of oil should be used in this engine?

In most areas, these engines take 10W-30 oil. In areas that are colder, or that reach below freezing, then a 15W-40 or 20W-40 viscosity can be used. If the temperature is consistently below -14 degrees F then synthetic oil should be used.


How do you change the oil filter on a Cummins NH 855 or NT 855 engine?

There are three types of oil filters, the full flow (with a center bolt), full flow spin-on, and the bypass.

• For full flow with a center bolt, first remove the drain plug from the shell to drain the oil. Clean any dirt near the shell before removing it. Remove the center bolt and the shell, element and the seal ring (discard the seal ring.) Remove the retaining ring from the center bolt, then the filter support, rubber seal, washer and filter spring. Remove the center bolt and the copper washer. Check the bypass valve to make sure it works freely. At this point of all the parts can be cleaned. Replace the element and any parts that show damage. Install a new copper washer and center bolt. Slide the spring, washer, rubber seal and filter support onto the center bolt, followed by the retaining ring. Put the new element in the shell, put a new seal ring in the head and install the drain plug.

• For spin on, use an oil filter wrench to remove the filter. Then, remove the capscrew and lock washer that attaches the spin on filter head, along with the spin-on adapter and the o-ring (discard the o-ring.) Clean the adapter and dry. Apply a coat of lubrication to the new adapter o-ring, and then install the adapter and new o-ring. Tighten the capscrews to 25 to 35 ft•lb. Put a coat of oil on a new seal ring and to the threads of the filter cartridge. Install a new sealing ring and filter to the adapter and tighten the filter cartridge.

• For bypass oil filters, a full flow filter must be used. Remove the capscrews for the clamp ring, cover and o-ring. Remove the element hold down assembly, followed by the filter shell. Clean and dry the hold-down assembly and the filter shell. At this point inspect the tee-handle, which will have an opening for oil. Make sure it is clean and free of debris. Then, install a new element into the shell, along with a hold-down assembly onto the stand-pipe. Tighten the assembly, install the cover, install a new o-ring and install the clamp ring to the cover and shell. Tighten the capscrews until the lugs on the clamp come together.


What is the normal oil pressure for a Cummins NH 855 or NT 855?

For regular and big cam engines, normal oil pressure is 15 psi at idle and between 50 to 70 psi at rated speed. For big cam II engines, the normal oil pressure at idle is 10 psi, and at the rated speed it is between 35 to 45 psi. For big cam III type engines, the normal pressure for this engine is 35 to 45 psi at rated speed. Be sure that the oil has reached a normal operating temperature, or between 200 and 225 degrees F.


What is the normal oil temperature for these engines?

The oil should not exceed 225 degrees F when measured at the oil pan. If it does, then stop the engine to prevent damage to the internal parts and components.


What is the normal coolant temperature for these engines?

The coolant should not fall below 160 degrees F while the engine is in operation, or exceed 200 degrees F.


What could cause a big cam III engine to have high or low lubricating oil pressure?

These engines improved the NH and NT855 engines with parts designed to improve efficiency, including a demand flow cooling (DFC) oil system. Be sure to first check any gauges to make sure they are functioning correctly. If the pressure is higher than 45 psi at the rated speed, or if it is 60 psi at idle (and continues to rise with engine speed) then the problem could be the plunger. If dirt or foreign material collect in the plunger barrel then the plunger can fail to move from the closed position. To fix this problem, disassemble and clean the pump and replace any worn parts. If the pressure is below 35 psi, a possible cause is air entering the oil. This can be seen by removing the valve covers and checking for air bubbles between the rocker levers. If you do not see air, check the DFC plunger to make sure it clean and able to freely open.


What is the oil pan capacity for my engine?

This depends entirely on the oil pan that you are using. Listed below are the ranges and the part numbers of the corresponding oil pans:

• High of 6.5 liters and a low of 4 liters : 10451, 10492-2, 125318, 187756

• High of 7 liters, low of 5.5 liters: 10474-2, 10774, 10777, 10811, 10850, 10850-a, 11055, 11102, 103949, 110626, 116916, 118784, 119330, 119382, 119586, 120905, 126818, 133879, 134271, 134279, 134283, 153739, 162377, 164776, 167186, 167429, 181768, 193625, 193629, 193631, 193634, 193635, 193636, 193637, 193638, 193639, 200787, 201839, 201842, 201843, 202283, 202284, 203561, 203563, 203564, 23841, 3002152, 3005178, 3005179, 3005181, 3005183

• Other pans are generally close to the above ranges. The only exceptions are the larger pans, such as 10779 (which have a low of 5.5 gallons and a high of 8.5 gallons) and 189672 (which has a low of 3.5 gallons and a high of 12 gallons.)


What is the oil pan capacity for an engine with a big cam III?

The oil pan capacity for this type of engine is 9 gallons.


How do you install a cylinder head on a NH 855 or NT 855?

To install a new head, first make sure that the surfaces and gaskets are clean. Install two guide studs into the block. Use the guide studs to install the head into the correct position in the block. Next, put two t-handles into the head and use them to slide the cylinder head into position on the block. Lubricate the capscrews with preservative oil and install the washers and capscrews. The proper tightening sequence for the capscrews is below. Tighten all of the capscrews to the specified torque before moving on to the next step:

• Step one- tighten to a torque of 20-25 ft•lb.

• Step two- tighten to a torque of 80-100 ft•lb.

• Step three- tighten to a torque of 265-305 ft•lb.

It is very important to tighten in the sequence above and to the torque values specified above.



See Cummins NH855 Parts for Sale

See Cummins NT855 Parts for Sale