Keep the 'Cool' in Cooling Systems
Keep the ‘Cool’ in Cooling Systems
Cooling system service fundamentals are unchanging, but the details — ah, the details.
Dave Hobbs/Motor Age — Changes in technology for the “David and Goliath” extremes of engines used in both hybrid passenger cars and light-duty diesel trucks definitely will ruin your day if you don’t know how they operate. Assuming all coolants are created equal can ruin your day as well. But the encouraging news is there’s good money to be made in cooling system repairs.
While oil change and spark plug replacement intervals have gone up over the years, surveys indicate 35 percent of vehicles inspections reveal an improper coolant level, improper coolant mixture or coolant leaks. All of this gives you the green light to sell proper cooling system maintenance and repairs to your customers.
The center focus on cooling systems always has been the coolant itself. Do you have enough coolant in the system? Are there leaks? What is the freeze protection? Is the coolant in good condition? Those used to be about the only questions regarding coolant, but times have changed.
Generally speaking, ethylene glycol has around 3 percent additives present to prevent corrosion, control pH levels and add color to the coolant. Added to the coolant is, of course, water, which averages around 50 percent of the coolant mix.
Most of us have seen the charts giving a clear picture of the ratio of the concentration of antifreeze vs. water in coolant. As antifreeze concentration goes up, the temperature protection goes up with it until that concentration goes past the 70 percent mark, where the freeze protection is actually reduced.
Testing has been simple, with a hydrometer that checks the specific gravity (and freeze point) of coolant. Hydrometers are cheap — some even fit in your pocket. But cheap can sometimes be expensive. Laboratory studies indicate that hydrometers can be as much as 23 degrees Fahrenheit off in their measurements for freeze protection.
In recent years, the refractometer has become more popular because it’s more accurate (within 1 degree Fahrenheit) and dependable for testing coolant strength to ensure ample freeze protection. They are also compatible for testing both ethylene glycol (EG) and propylene glycol (PG), while the hydrometer measures either one or the other.
Source: Motor Age