resurected my post from the dead.....
this is a post i made on another forum a long time ago, and should clear up a lot of myths/questions about coolant:
What is coolant?
-water, wich is an excellent heat transfer fluid but it freezes and causes corrosion.
-Glycol is added to prevent freeze and boil-over protection. it reduces the heat transfer capability of water.
-Supplemental Coolant Additives (SCA's)......Not all coolants are the same, but conventional fully formulated heavy duty coolants (non-organic acid) contain many of the same additives:
*nitrites protect iron (and steel) from cavitation, pitting, and rusting.
*nitrates protect protect solder, aluminum, magnesium
*silicate is also added for aluminum protection
*tolytriazole and sometimes mercaptobenzothiazole (wtf?!) are used to protect copper and brass
*phosphate or borate are pH buffers used to control alkalinity.
The water and glycol will remain in service indefinatly barring any contamination. The SCA's will become depleted and must be replaced.
Functions of coolant are:
-removing heat from engine
-protect from corrosion
-prevent freeze damage as well as boil-over.
-prevent cavitation (pitting) in diesel engines.
what is cavitation you ask? AWESOME, i know the answer.....
Cavitation is when the movement of cylinder liners causes tiny air bubble to implode, and basically act as a "jack hammer" on the liners (or block). its like sandblasting, that happens every time the piston fires. it can eat water pump impellers to NOTHING! i have seen it, and it is crazy.
Cavitation, and corrosion are the reasons why the SCA levels must be maintained. you may be thinking the more SCA the better off you are.....NO! Too much SCA will no stay "dissolved" in the coolant, and will cause scale, and goo. the fallout will KILL your water pump seals, as well as insulate everything it forms on, causing overheating !!!
COLORS!!!! color is the best indication of what coolant type you have, however if different types have been mixed, it may be brown....brown is ok, unless its cloudy chunky brown wich is rust. clear brown is just an indication that someone mixed green with purple, or something like that. colors often can be the same type of coolant, just from different companies.
Conventional Automotive coolant:
-green
-high in total dissolved solids
-high silicate and phophate content
-tough on seals
-requires addition of SCA
-service life of 2 years or 250,000 miles
-compatible with all technologies
-not a product of choice by any OEM
Conventional Fully-Formulated Coolant
-green, pink, blue, purple, orange
-low TDS (your seals thank you)
-very low phosphate
-maintained with SCA's (comes pre-charged)
-service interval of 6 years or 600k miles
- OEM approved!
Extended Life Coolants - organic acid
-red, orange, yellow
-low TDS
-phos. and silicate free
-NOT COMPATIBLE WITH OTHER TECHNOLOGIES! the organic acid coolants react with the non organic acid, and become neutral, useless.
-orange colored is NOT for diesels! your engine will cavitate (gm dexcool)
-maintained with an "extender" at 3 years or 300k miles, service life of 6/600k
side note: there is nothing "extended life" about the extended life coolants, it was a name that was used as a marketing ploy, still used just to identify the organic acid coolants.
mixing the ELC and Conventional....you shouldnt do it, but if you buy a truck that has it mixed, or you must mix it in a pinch..........no big deal just treat it as conventional coolant, and add SCA to appropriate levels. as stated before, the color will be brown, but brown is ok as long as its clear. cloudy/chunky brown is BAD.
if coolant becomes cloudy.....drain, flush, and refill the system with new coolant. possible causes are rust, fallout, or other contamination.
freeze point is a direct relationship to the water/antifreeze mix ratio. a 50/50 mix has a freeze point of -34*F, and for most parts of the world that is perfect.
maintaining proper SCA levels can be done 3 ways,:
-liquid for vehicles that have no filter, or are using a non-charged coolant filter.
-charged filter: there are different charge levels depending on your needs, or if the system is up to level a blank filter can be used.
-extended service filter: same as the regular filter, however it has 3 sacrificial metal plates that corrode through and release small doses of SCA when the levels get low. this filter will keep your sca levels within spec for about 150,000miles, 15 months, or 3000 hours. it will replace 8-10 ordinary charged filters.
maintaining ELC:
use a elc test strip, add extender once after the test strip reads a failed coolant, the next time it fails (or if it never passes after the extender is added) drain, flush, and refill with new coolant.
for test strips, i highly rec. the penray 3 way test strips for conventional, and the penray elc test strips for...yes....elc. they are very clear cut, and simple to use. the color chart supplied with the strips tells you everything you need to know, and how to "fix" your coolant if its out of spec.
