Diesel Coolant

Diesel Coolant

7/28/2015
           

This article was trigger by some definitions supplied by Jim2 (Jim):

There once was a time when you could buy diesel coolant by color, but no more.  Therefore, you need to know what kind of coolant you have in your diesel engine when you need to add coolant.  You can mix colors but your can't mix coolant types.

There will be no endeavor to prove which types of coolant are better. We only intent to educate your to know what to be asking for when you buy coolant to add to your system.

We found this excellent article on RVcuzer.com by Mark Quasius that should be read first; HD Diesel Engine Coolants for RVs.  We copied this article into our web site to insure it availability.  The link to the original article is on the bottom of the web page.
 

SCA = supplemental coolant additive

The chemical cocktail added to the basic ethylene glycol or propylene glycol, to reduce scaling, corrosion & cavitation of the coolant system components.

DCA2 & DCA4 are the two different types of SCA based on their different chemical cocktails - nitrite/borate/silicate versus nitrite/molybdate/phosphate/silicate - which additive to use is specified by the engine manufacturer as part of their coolant specifications.  Many recommend not mixing these two different chemical additives, some say its ok to mix them. each has pluses & minuses.  Best overall approach is to follow the recommendations of your engine manufacturer.

DCA4 has been historically specified by Ford, International and Cummins.
DCA2 has been historically specified by CAT, Detroit Diesel and a few others.
 

Heavy Duty Conventional Diesel Coolant

This is how adding SCA's to coolant started.  At initial fill of the coolant, the SCA additive is added and then periodically tested to maintain proper SCA %.
 

Heavy Duty Fully Formulated Diesel Coolant

This is how almost all SCA coolant is delivered today.  The coolant comes pre-charged with SCA for initial fill, followed by periodic testing to maintain proper SCA %.
 

Heavy Duty Diesel Extended Life Coolant (ELC)

Uses a variety of proprietary "inhibitors" instead of SCA and therefore does not require testing or adding SCA, but requires the addition of an "Extender" after so many miles of use.
 

Organic Acid technology (OAT)

Carboxcylic/fatty acids are used to replace the function of the previously used SCAs. This type of coolant can last 6 years/ 600,000 miles with a additive recharge at 3 years/300,000 miles.
 

 

This is a transition coolant with SCAs included in OAT coolant at a much reduced level than in typical SCA coolants.

A two part article on SCA coolant:  Part I,  Part II
 

Note:

In case you missed it in the recommended article to read above, OAT Extended Life Coolant is good for 600,000 miles or 6 years what comes first but needs an Extender Charge at 300,000 miles or 3 years.

Emery Nash (Emery) found Understanding coolants with some informative reading.

Escapees HDT Forum threads on diesel coolant:

 

Agents are arranged in order of numbers of mentions in Forum threads.

Type Color Name Literature
HOAT Red Recochem STP® Heavy Duty Diesel Extended Life Antifreeze/Coolant  
HOAT Red Recochem STP® Heavy Duty Diesel Extended Life 50/50 Pre-diluted Antifreeze/Coolant  
HOAT Red Shell Rotella® ELC Extended Life Coolant/ Antifreeze  
HOAT Red Cat ELC  
OAT Orange Recochem STP® Extended Life Antifreeze/Coolant  
OAT Orange Recochem STP® Extended Life 50/50 Pre-diluted Antifreeze/Coolant  
OAT Red Mobil Delvac Extended Life Coolant/Antifreeze  
OAT Red Mobil Delvac Extended Life 50/50 Prediluted Coolant/Antifreeze  
OAT Red Cummins Fleetgard ES Compleat OAT Brochure (pdf)
OAT Red Peak Final Charge® Global Extended Life  
PreMixed SCA Purple Recochem STP® Heavy Duty Antifreeze/Coolant  
PreMixed SCA Purple Recochem STP® Heavy Duty 50/50 Pre-diluted Antifreeze/Coolant  
PreMixed SCA ? Peak Fleet Charge  
PreMixed SCA ? Peak Fleet Charge 50/50  
PreMixed SCA Magenta Cat DEAC  
PreMixed SCA Blue Cummins Fleetgard ES Compleat EG  
PreMixed SCA Pink Cummins Fleetgard Fleetcool Brochure (pdf)
PreMixed SCA Purple Prestone®  Heavy Duty Antifreeze/Coolant  
PreMixed SCA Purple Prestone®  Heavy Duty Extended Life Antifreeze/Coolant