Tan 1990s Ford F-150 with hood up beside Prestone antifreeze and…

Top - EXPENSIVE
Bottom - affordable



This truck's coolant has been neglected to the point that all the rust in the system blocked up the heater core. It took about 20 minutes with a garden hose blasting back & forth into each heater hose to unplug it, and rinse out something that looked like baby vomit.

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THEN, we used the water pump (whose impeller had not yet rusted away) to empty & flush the rest of the cooling system out of the open heater hose nipples, while refilling the radiator continuously with tap water (which is when the top pic was taken). After that ran reasonably-clear, the tap water was stopped so it could pump most of that out before dumping the lower hose, and then refilling with concentrate & distilled water. These trucks need about 2 gallons of each (concentrate & water).

For the correct coolant type, follow the "Quick Reference Charts" link on this page:
https://www.fcsdchemicalsandlubricants.com/main/

Ready-mixed (50/50) coolant is MUCH more expensive & lower-quality than concentrate plus distilled water. You can see from these prices that 2 gallons of coolant (1 concentrate plus 1 distilled) will cost me $11.69. I couldn't even get 1 gallon of ready-mix for that.

NEVER buy "long-life" coolant - it doesn't last as long as normal-life. The "long-life" label only applies to its antifreeze/antiboil characteristic - not to all the OTHER chemistry, which is what really matters.

See also:
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Owner caption November 2018 · Photo 0 of 5000