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Diesel Antifreeze Replacement

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(1) Park the truck with the engine facing downhill (if possible), block the wheels, and allow the engine to cool. Remove the radiator cap, then open the radiator drain with a pair of pliers. A 3' piece of 1/4" tubing can be attached to the valve outlet to direct the anti-freeze into a bucket. You should get four to five gallons out of the cooling system.
coolant drain valve open valve with pliers

(1a) You may need to loosen the boost line hose clamp to get access to the drain valve - use an 11mm wrench. While wiggling the pliers to break the valve corrosion loose, turn the valve CCW and unscrew/pull it out.

loosen boost hose clamp move clamp to side coolant flowing from valve
(2) Inspect the accessory drive belt for tears or cracks. Flip the belt back and check the ribs where the belt wraps around the idler pulley. Short cracks across the ribs are OK, but cracks along the length of the belt or frayed belt edges indicate that it is time for replacement. belt inspection belt inspection
(3) Remove the coolant overflow hose from the radiator nipple with a pair of pliers to release the clamp. Remove the coolant recovery bottle by snapping it upward to free it from the mounting slots. Dump the old coolant and flush the bottle to remove sediment.
overflow bottle overflow bottle mount Clean again!

(4) When all of the anti-freeze has drained, close the valve and refill the radiator with water. Place cardboard in front of the radiator and start the engine. Engage the exhaust brake (if you have one) and allow the engine to warm enough to circulate the coolant. Stop the engine and drain the radiator.

blocking the radiator
(5) Now, repeatedly refill the radiator, circulate, and drain the system until the drained water does not show dye from the coolant (this takes about six fill/drain cycles for my truck). When the water runs clear drain the cooling system as much as possible.

(6) Close the radiator drain valve and reinstall the boost hose clamp.

Tighten the clamp to 95 in-lb [11 Nm] with an 11mm wrench.

Install the coolant overflow bottle and reconnect its hose to the radiator barb.

close drain valve and tighten the boost hose clamp

(7) Add three gallons of straight (undiluted) antifreeze to the radiator. Use low-silicate antifreeze that meets ASTM4985 (GM6038M specification) criteria. FleetCharge is available from Cummins.


use antifreeze formulated for diesel engines

(8) Finish filling the radiator with water. Add enough 50% antifreeze / 50% water mix to the coolant overflow bottle to bring it to the "full" mark. Start the engine and add water to the radiator as the engine warms up. When the coolant level stabilizes, install the radiator cap. You are done.

(9) Check the overflow bottle for several days and add 50% antifreeze as necessary to keep the bottle within the "add" and "full" marks.

From Steve St.Laurent :

Here's how I did mine and I got approximately 5.5 gallons into the system, first I opened the petcock on the radiator (turn it, then pull on it a little, turn, pull, turn, pull - until it starts draining), that will drain the fluid out of the overflow bottle, once the overflow bottle is empty then take the radiator cap off. Now pull the hose connector off the top of the engine and remove the thermostat. Once it stops draining, pour distilled water into both the inside and outside holes in the thermostat hole until you see clear water flowing out of the radiator. Now pour in straight 100% coolant into those same two holes until you see coolant running out the radiator. Close the radiator petcock. Some of the water and some of the 100% coolant will be trapped in the system - should be around 50/50. Now pour in either pre-mix or mix 50% coolant with 50% distilled water in through the thermostat hole until the system is as full as you can get it. Then put the new thermostat in and the top radiator hose connector. Finish filling the radiator with the mix, close the radiator cap and then fill the overflow bottle. Run the truck until it's warmed up (so the thermostat opens) and then check the overflow bottle again.
Using this method I was able to get in approximately 5.5 gallons (actually poured in more than that but some of it pours out) and I didn't have any problems with trapped air because I was backfilling the system from the engine to the radiator. You want to use distilled water only so you don't get mineral deposits in your coolant system.

Excerpts from Cummins Service Bulletin 3666132-01:

Storage Stability

Liquid SCA/ESA typically has a shelf life of at least 2 years from the time of manufacture when stored at temperatures ranging from -7° to 55°C [19° to 131°F].

Note: Solid material, liquid turbidity, or layering at the top of the liquid is allowed if it will dissolve and disperse by stirring the solution and warming it to a temperature between 2° to 67°C [36° to 153°F].


Note:L See also Operation and Maintenance Manual, B Series Engines, Bulletin No. 3810205.

    The B Series engine normally does not require SCA because the engine normally does not experience cast-iron cavitation corrosion. The Cummins B Series engine has not shown any tendency toward cast-iron cavitation corrosion. Also, the B Series engine does not have an integral coolant filter.
     Therefore, the B Series engine coolant recommendation is to use low-silicate antifreeze meeting ASTM D4985 specifications and to drain and replace it every 320,000 km [200,000 mi], 2 years, or 6000 hours of operation (whichever occurred first).

    Use of fully formulated coolant in this engine is acceptable but not required. Cooling systems perform best with distilled or deionized water mixed 50/50 with antifreeze.
     The primary purpose of antifreeze is to lower the freezing point of the coolant. Additional performance characteristics of coolants that are affected by the use of antifreeze include boiling point and vapor pressure. Antifreeze decreases vapor pressure, which is very beneficial to the reduction of cavitation.
    A 50/50 mixture of antifreeze and water provides optimum boiling and freezing point protection for engines. An antifreeze concentration in excess of 60 percent must never be used since it increases the possibility of forming cooling system gel, which results as silicates precipitate out of solution. However, an antifreeze concentration less than 40 percent increases the possibility of coolant freezing and liner pitting. Therefore, Cummins recommends an antifreeze concentration range of 40 to 60 percent.


Additives Function
Borate and Phosphate Maintain proper pH of coolant and provide some corrosion protection
Nitrate, Silicate, MBT, TT, and Some Organic Acids Provide corrosion protection for various metals
Nitrites Provide cast-iron cavitation-corrosion protection
Polymers Provide scale and deposit formation protection
Surfactants Provide some antifouling protection against oil and dirt contaminants in the coolant
Defoamers Prevent coolant from forming a stable foam (that can cause pump cavitation and overheating)
Molybdate Provide cast-iron cavitation and aluminum corrosion.