Blowin' Smoke

An Editorial by dieselmann
Volume 7; December 99: Cooling system maintenance.

I decided to write this article in response to several questions on cooling system capacity, drain and refill schedules and anti-cavitation conditioner ratio. It's also to rectify some misconceptions for which I may be responsible due to misinformation from Ford.
It doesn't help when there is a lack of, or conflicting, information, either. I can find no service publication from Ford which shows the cooling system capacity for the 99+ F-series or Econoline with the PowerStroke engine--they list every other one but the PSD--but the owner's manual diesel suppliment shows 32.75 quarts for the F-series and 30 quarts for the E-van. The 97 specifications book shows the capacity for the F-series as 23 quarts (E-vans 31 quarts) including three pints of FW-16. Navistar simply shows the cooling capacity of the engine alone to be 12 quarts for all years.
Now, I've never done a complete drain and refill on a PowerStroke, but when draining the radiator, I've never gotten more than 5 gallons (20 quarts) from 97 and earlier F-series, and about 5 1/2 gallons (22 quarts) from 99 F-series. I can't see any reason for such a descrepency of coolant not drained from the engine (3 verses 10 quarts) as the only difference between these trucks is the size and configuration of the radiators, which had been drained, and the expansion bottles. The only way I can see to definitively settle the question of the 99 PowerStroke cooling system capacity is to perform an engine replacement and see how much coolant is required to fill a dry engine.
For now, the best course is to refill after draining with a 50/50 mixture of coolant and water and then testing the coolant protection level. This can be done with a variety of hydrometers, spectrometers, or with test strips. A 50/50 coolant mixture provideds a protection level of approximately -40°F; 30% antifreeze protects to about 0°F; 25% to about +10°F. What this means is on a cooling system with a capacity of 24 quarts, to go from a protection level of +10°F or 25% to the optimum 50/50 you would have to drain 6 quarts out and add the same of undiluted antifreeze; to drop from 0 or 30% you would drain and 4 quarts. On a system which hold 32 quarts, to drop from 25% would require 8 quarts, and from 30% 6 quarts of antifreeze. This method can also be used if you are checking your coolant protection between services.
The information on correct amounts of coolant conditioner are similarly confusing. The owner's manuals state to add four pints of FW-16 when refilling the cooling system, but Ford has a TSB which says add two, and, as I said, the 97 spec. book says three. Finally, the FW-16 bottle says to add four ounces to each gallon of coolant capacity.
The makers of the DCA4 coolant conditioner--Fleetguard--provides test strips to monitor the levels of the conditoner, and although the strips are easy to use, the chart provided can proved to be confusing and missunderstood--the chart was intended for use in fleet vehicles with large cooling system capacities.
In order to clear up this confussion, Diesel injection service has provided the needed information. The chart is set up in units of conditioner per gallon of coolant capacity and by compairing the molybdate and nitrate levels on the chart you can determine the amount of conditoner in your vehicles cooling system. The recommended level of condtioner is 1.5 to 3 units of conditioner per gallon of coolant capacity, and each pint of DCA4 equals 5 units of conditioner. By dividing 5 by the gallon capacity of your cooling system you can determine how much one pint of condtioner will change the levels in your cooling system. In a 24 quart cooling system, one pint of conditioner will change the reading 0.8; in a 32 quart system it will change the reading 0.6. So if you test your system and find that the units per gallon is at 1.2, adding one pint will bring the level to 2.0 for a 24 qt system and 1.8 on a 32 qt system. A second pint would bring the level to 2.8 or 2.4, respectivly.
You might ask, if all you need to do is test and adjust the coolant and conditioner in your cooling system, why would you have to drain and refill? The answer to that is particulates still accumulate in the cooling system--from wearing parts or chemical changes. To prevent blockage of the radiator or rapid depletion of the chemical components of the coolant and conditioner, the build up must be removed and the only way to do this is to drain the system. The periods between services can be extended with ELC's or filters, but eventually you will still need to have this done.

Charles David Ledger; dieselmann1999

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