A Science Experiment Under Your Hood

| May 03, 2005
  1. Look up the cooling system capacity in the owner’s manual in gallons. Then find the line representing the number of gallons corresponding to that capacity in the chart in the left hand column. Once you have found the correct line, follow it over to the right until you’ve found the percentage of coolant you got reading the strip or the refractometer (listed along the top). Below that percentage, in the line representing the capacity for your system, will be the amount of water or antifreeze in quarts you’ll have to add to correct the concentration. The numbers to the left of center are the quarts of antifreeze you need to add. The numbers to the right of center are the quarts of water you have to add. Once you’ve found the number of quarts of water or antifreeze to add, drain that much out of the system and add the amount indicated.

  2. If your need-release filter is working, and you have been adding only the proper coolant, the color of the protection level patch should match (Detroit Diesel Power Trac only). Also, the nitrite level should be well within the approved range, which is 800-2,400 ppm. In fact, it should be very close to the ideal of 1,200 ppm. If below 800 ppm, somebody has probably been adding plain antifreeze or water. If that happens, purchase a container of Penncool 3000 or Detroit Diesel Powercool 3000. Follow the directions on the test strip container right below the sample color patch that matched the color of the strip. Based on the capacity of your cooling system and the nitrite concentration in ppm, they will tell you how much SCA liquid to add. For example, when using the Penray supplies, if the concentration is 400 ppm, you add 1 pint for each 8 gallons of system capacity. Drain enough coolant out to add the correct amount of SCA concentration and then do so.
  3. If using a need-release filter, the only way the system will have too much in the way of nitrites is if someone has been overdosing it by adding them when they are not needed. In the rare case when the coolant does have too high a concentration of nitrites, you’ll need to drain out a few gallons of antifreeze and add plain antifreeze-deionized mix that has no SCAs or the proper TMC RP-329 TYPE A coolant, mixed with deionized water. Some overdosing is OK because if you stop adding SCAs, the level will diminish as you drive. Detroit Diesel recommends diluting them when the concentration passes 4,000 ppm. You drain half your antifreeze, refill and retest. Penray says the problem isn’t critical until the concentration passes 6,000 ppm. If your reading is in that range, Penray suggests you completely drain and refill with the right coolant, then retest.
  4. Once the adjustment has been made, run the system for a few minutes to distribute the SCAs or plain antifreeze and then retest. Readjust if necessary in the same way.
  5. Check the date, mileage and hours written on the need-release filter. If the filter is due for a change, change it as described below. A filter overdue for a change can contribute to a low nitrite or overall protection level.
  6. To change the filter, make sure the engine has been stopped for a while and allowed to cool. Cautiously release the radiator cap to make sure there is no pressure in the system. Get a catch pan and place it under the coolant filter.
  7. Position a strap wrench of appropriate size around the filter so it will grab if turned counter-clockwise as viewed from below. Then use the wrench to loosen the filter. Once it can be turned easily, turn and remove it with your hand.
  8. Thoroughly wipe down the coolant filter mount with a clean rag.
  9. Unwrap the new filter. Look up the miles or hours on the vehicle on the dashboard. Write the date and miles or hours on the filter housing in the area provided for that purpose (the black Penray filter has a white area for those numbers). Then coat the entire top surface of the rubber gasket with clean engine oil or white grease. Be careful not to get oil inside the filter.
  10. Read and take note of the tightening instructions on the new filter. Carefully start it onto the threads on the coolant filter mount by holding it as vertical as you can and turning gently. Once it turns easily on the threads, tighten by hand until the gasket just contacts the mounting. Then reverse the strap wrench and turn the additional number of turns specified.
  11. Refill the cooling system with TMC RP-329 TYPE A coolant only and replace the radiator cap. Run the engine until the thermostat opens. Stop the engine, carefully remove the cap and top off the system as necessary.
  12. If your coolant nitrite concentration was incorrect, take appropriate measures to make sure only the correct TMC RP-329 TYPE A coolant is added and that nobody, including a service shop that may do oil changes for you, adds regular coolant or SCAs or attempts to replace the need-release filter with a standard coolant filter.

Penray’s Funk says it’s also a good idea to send your coolant to a test lab for analysis every one to two years. This will warn you if any serious problems are developing or if something has gone wrong in your testing. This would also be advisable if using ELC and there is any chance it may have been diluted with the wrong type of coolant.

For further information, please contact the following:
(925) 842-1000

Caterpillar Engine Div.
(309) 675-1000
www.caterpillar.com, click engines

Shell Oil Co. U.S.
713 241-6161

Detroit Diesel Corp.
(313) 592-5000

Fleetguard, Inc.
(615) 367-0040

The Penray Companies
(800) 322-2143

(602) 252-0280
(Amalgatech does coolant analysis.)

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