So I have not seen a really really good write-up on coolant so I wanted to take a min and give some info. Some say coolant can be as important as oil to the long term life of your truck....let me know what you guys think.
Most people think as long as antifreeze isnt freezing and the truck isn't overheating then the coolant is acceptable. When in fact studies have shown that over 40% of engine problems are indirectly or directly related to improper coolant formulation or poor upkeep of coolant additives.
Diesel engine coolant should contain:
-Water with aceptiable chem properties.
-Antifreeze suitable for deisel application.
-Supplemental Coolant Addivtive (SCA)
Water alone provides 10-15 degrees less boil-over protection.
Untreated water (even drinking quality water) tends to be corrosive in the cooling system enviroment. Water alone should never be used as coolant except in an emergency.
Most local supplies can be used as coolant when treated with SCA and Some areas have high mineral content or corrosive chemicals that cannot be treated with SCA.
Corrosion - Attack of metal surfaces. Can result in perforation of the metal wall, such as cylinder walls.
Deposits - Coating build up on cooling system surfaces. Drastically reduces heat transfer and plugs passages. Localized overheating can result in cavitation, cracking or seizure.
Ethylene Glycol (EG) based antifreeze is the most available and is suitable for freeze and boil over protection.
Propylene Glycol (PG) based antifreeze has better cavitation corrosion protection then EG and is preferred for diesel engines. However, the limited availability of low silicat PG antifreeze prevents widespread use in diesel engines at this time.
Methyl alcohol or methoxy proponol based antifreeze are no acceptable.
Antifreeze should have a 0.10% silicate level or less. Using high silicate antifreeze in diesel engines can result in silicate gelation (the formation of green slime) which plugs collant passages in the engine and radiator.
Your antifreeze concentration should be between 40-60% depending on expected ambient temp. Never exceed 68% concentration because freeze protection is diminished and the high concentration can plug coolant passages and cause overheating or deposit on water pump seals causing seal leakage.
Min 40% for imporved boil-over temp.
The differences in engine design, load factor and utilization rate require specialized products to protect the diesel engine coolant system. SCA's have been used in diesel engines since the mid 1950's to meet those special needs. SCA provides:
Buffer - control PH
General Corrosion Protection
Cavitation Corrosion Protection
Scale Inhibitor - prevents deposits on hot surfaces (1/16" of scale on cylinder sleeves retards heat trasfer as much as 4-1/2" of cast iron!!!!!!)
Excessive scale buildup can cause piston score damage.
Anti-Fouling - limits oil and dirt build-up on metal surfaces
SCA precharge for initial system fill is 3-6% by volume in liquid form. A srevice dose is then added every 500 hours or 15,000 miles to make up for additive lost due to depletion and dilution. Typical service dose is 1/3-1/4 that of the prechage amount. Do not exceed recommended treatment levels! Overtreatment can cause additive to precipitate onto water pump seals and degrade their performances.
Information from Ford booklet titled Prevent Cavitation.