Draining NHC-250 cummins block

[5tondeuce]

Hi all,
Can anyone tell me how to drain the cooling system in a NHC-250 cummins. I've looked through the tech manuals and searched the forum with no luck. I have already drained the radiator but I can not figure out how to drain the block. Thanks for the help!
Chris

 

[WillWagner]

The radiator is the lowest point, that should suffice. You will never get all the coolant out unless you pull the liners out of it. There is a 1/4 pipe plug at the exhaust side , rear of the engine. You can take that out, but it all still will not come out.

 

[73m819]

there also a drain under the oil cooler

 

[Earth]

If you're putting in a block heater then the 1/4 in plug Will mentions is lower than the plate for the heater. There was about a gallon in the block after I drained the radiator to install my block heater.

 

[5tondeuce]

Thanks very much guys, this helps alot

P.S. I had flushed the cooling system with water so I was just trying to get as much as I could out before I add antifreeze.
Thanks again for the replies
Chris

 

[emr]

Then make sure U take the WHOLE petcock out with a think a 9/16 open end, could have been 1/2 but it was a whole 4 weeks ago, ALOT more can come out if U do that,

 

[DOCUSN1]

Yep just like emr said pull the whole petcock and blow that out to. Dont forget to add your SCA and check its level when your done.Mark

 

[5tondeuce]

Hi Mark,
At the cost of asking a stupid question, What does SCA stand for?
Thanks,
Chris

 

[DOCUSN1]

Hi Chris no cost as I belive the is no stupid question ever. SCA stands for supplemental coolant additive (if I spelled it right) your cummins diesel engine has what is called wet liners and the sca helps stop what is called cavitation, it will contain nitrates and help control PH. You can buy new antifreeze precharged or use regular and go to NAPA and buy a small can of additive. If you have a tractor suppy store near you they carry fleetcharge which is precharged with SCA and only costs 1 dollar more that regular antifreeze. Go to www.fleetchargeantifreeze.com for more in for on SCA and specs. If you have any questions feel free to ask, thats why we are all here to help each other out and enjoy our MV. Mark

 

[5tondeuce]

Hi Mark,
I did not know anything about this additive so thanks for the info.I am familiar with cavitation and ph. Is the cavitation caused from the vibration from a diesel engine.
Thanks again
Chris M

P.S. I bought heavy duty antifreeze from napa but I'm not sure if it is precharged but I will check.

 

[Earth]

I just did one of my 5 tons with new coolant when I did the block heater. I used Rotella ELC that i got at NAPA. It is pre-mixed 50/50 and doesn't require any SCA additives. Recommended for Cummins diesels. It costs too much. I'm doing the other truck today or tomorrow (block heater) and depending on how the coolant looks, I'm going to get the Fleetguard at Tractor Supply.

 

[DOCUSN1]

Yes vibration causes it to happen read the following Mark
Cooling System Maintenance for Heavy Duty Engines

There are many cooling system problems and failures. Most of these problems have occurred due to incorrect information and maintenance practices. The following will address these problem areas by correcting the erroneous information and listing the proper maintenance practices. The chart shown below is a listing of the six most common problems seen in today's cooling systems. Along with each problem is a description of how it occurs, how it affects your engine and, most importantly, how to prevent it.
PROBLEMHOW IT HAPPENSWHAT IT CAN DOPREVENTIONRust*Oxidation within the system.Clog the system. Cause accelerated wear.The inhibitors in a quality Supplemental Coolant Additive prevent the oxidation for rust to occur.Scale
(Water Hardness)Present in all tap water are salt minerals, especially calcium and magnesium. These minerals can solidify and adhere to hot metal surfaces.1. Clog system passages. Deposit on high temperature areas and reduce the heat transfer rate causing hot spots. This results in uneven metal expansion, scuffing, scoring, accelerated ring wear and, eventually, cracked heads and/or blocks.The Supplemental Coolant Additive keeps salt minerals in suspension so they cannot deposit on engine metal surfaces or clog passages.Acidity
(pH)Ethylene glycol antifreeze reacts with oxygen in the air and forms acid. A loose head gasket or other leakage can allow sulfuric acids formed by the burning of fuel to leak into cooling system.Corrode iron, steel and aluminum.A quality Supplemental Additive neutralizes acids to prevent corrosion. Coolant pH should be 8.5 to 10.5.Pitted Cylinder LinersConstant vibration of the cylinder liner causes a momentary vacuum to form on its surface. Coolant boils into the vacuum and vapor bubbles implode on the surfaces of the liner, digging into unprotected liners.Cause pits which can extend over time, through the thickness of the liner and allow coolant to enter the combustion chamber or crankcase.The Supplemental Coolant Additive coats the liner with a thin film to protect it from erosion without impeding heat transfer.FoamFoam - The aeration of coolant - occurs from air leakage into the system.Adds to the Cavitation erosion problem, particularly in the areas of water pump impellers.A quality Supplemental Coolant Additive has an anti-foam agent to prevent formation of air bubbles. This foam prevention agent is effective at all temperatures, even during startup.Pitted Water Pump ImpellersFlow rates and turbulence are high at the impeller blade. This causes Cavitation. In addition, there is a possibility that abrasive particles are present in the system.Cause loss of pump efficiency and total pump failure.The Supplemental Coolant Additives protect the impeller from Cavitation erosion and the filter holds particulate matter to reduce abrasive wear on cooling system components.*It should be noted that rust can appear even within a chemically protected system when oil is present in the coolant. If you do notice the presence of rust, the oil cooler should be inspected for possible leaks.STARTING RIGHT Before changing the coolant, the system should be thoroughly flushed to remove any contamination. A clean system is free of solid and liquid contaminates including oil.
MAKE-UP WATER
Proper coolant system maintenance requires a quality make-up water. All make-up water is corrosive but water with high mineral content cannot be made fit for use. As soft of tap water as possible should be used. Tap water that has been softened by some type of salt or chloride process should not be used. Most engine manufacturers have set up specifications for water used in their engines. The following chart shows some of these specifications.
CaterpillarCumminsDetroitHardness100ppm300ppm170ppmChlorides50ppm100ppm40ppmSulfates50ppm100ppm100ppmTotal Dissolved Solids250ppm500ppm340ppmNote: When contacted, Mack informed us that there were no limits on water used in their engines. ( PPM - Parts Per Million )
ANTIFREEZE
Antifreeze, ethylene glycol, propylene glycol or long life / extended life, should be used in the cooling system year around. The glycol in the antifreeze provides freeze protection. It also provides a stable environment for gaskets and seals. These same gaskets will shrink in straight water and leakage could occur.
Some of the major problems we see in cooling systems today occur due to antifreeze related problems. One of the most publicized problems is silicate gelation/dropout. Silicate gel problems have increased in frequency since the early 1980's. The two major causes of this problem are:
1. High Silicate Antifreezes
2. Over concentration of antifreeze and/or Supplemental Coolant Additives.
All antifreezes used in today's heavy duty engines should meet GM 6038M or ASTM D-4985 specifications for silicate content. The antifreeze concentration should be held between 40% and 60% (40% antifreeze and 60% water to 60% antifreeze and 40% water). A 50% / 50% blend is ideal.
Another problem caused by over concentration is water pump leakage. In a study by Cummins Engine Company, 54% of the water pump failures they examined occurred due to over concentration. 78% of the total pumps examined showed over concentration regardless of the cause of the failure.
SUPPLEMENTAL COOLANT ADDITIVES
Using the proper amount of a high quality Supplemental Coolant Additive is very critical in preventing the problem mentioned in the chart
on the previous page. When filling a newly cleaned system with fresh antifreeze and water, a Supplemental Coolant Additive is required. These additives contain many inhibitors not found in today's antifreezes or if present in the antifreeze, they are at very low concentration levels (unacceptable for engine protection). When pre-charging, be sure to use the proper pre-charge filter for your size cooling system or 4 ounces(120ml.) of liquid Supplemental Coolant Additive per gallon(3.8 ltr.) of coolant (4 oz.(120ml.) requirement based on the most common Supplemental Coolant Additives). In either case, be sure to follow the Supplemental Coolant Additive manufacturer's specifications.
SERVICE
Supplemental Coolant Additives are used up (depleted) while in the process of protecting the metal surfaces which are in contact with the coolant. These additives must be replenished through the use of filters containing SCA's or a liquid SCA at specified service intervals to maintain the proper concentration levels.
PERIODIC DRAINING AND FLUSHING
Antifreeze breaks down to corrosive acids due to temperature cycles within the cooling system . The coolant can also become contaminated by dirt, oil, combustion gases and spent inhibitors. While a high quality coolant filter will remove the solid contaminants, it will not remove the oil or combustion gases. Due to the breakdown of the antifreeze, all engine manufacturers recommend periodic draining and flushing. Caterpillar and Detroit Diesel recommend annually draining and flushing while Cummins and Mack recommend a maximum of two years.
There are many specialized products on the market today which can help you develop a quality cooling system maintenance program. The antifreeze concentration level is a key area which could lead to silicate gelation and water pump leakage. The recommended range is 40-60% based on ambient temperature. The use of a refractometer or hydrometer will insure the glycol concentration levels are maintained properly.
There are several different types of Supplemental Coolant Additive test kits on the market. The primary types check one of the following:
1. Sodium Nitrite
2. MBT
3. pH
Use the test kit recommended by your Supplemental Coolant Additive supplier.
CAUTION: Test strips or testers which register the pH as the sole determining factor in adding your Supplemental Coolant Additive should not be used. For further information regarding antifreeze, refer to TSB-96-6.

 

[bcowanwheels]

its not cavitation its electrolisis and it pits the outside of the cylinder linners and will eat plum through the cylinders if you dont keep your acidity level at the right level. its the worst in the middle between each cylinder to cylinder. you can get test kits at any semi truck parts house. just tell them you need a antifreeze test kit. comes with strips you dunk in the antifreeze sample and then compare the coolors it turns to the scale on the bottle.