Need-release filters can make conventional coolants as easy as ELCs.
Diesels that get regular cooling system care and oil and filter changes will rarely develop mechanical problems unless subjected to extreme driver abuse.
Your diesel’s cooling system is like a “science experiment,” says Garrett Funk, northeast regional manager for Penray, because of an interaction of metal, water, heat and oxygen with the acids formed in combustion.
Truck diesels have replaceable cylinder liners so they can be rebuilt easily. But those cylinder liners vibrate, which makes them vulnerable to pitting if the coolant is corrosive. Unprotected cylinder liners can develop pits that may end up creating a hole right through the metal, Funk says.
Traditional coolants use supplemental coolant additives (SCAs) containing nitrites for cylinder liner protection and other materials to protect the rest of the cooling system. The materials in the SCAs break down as they defend the metal surfaces, so they must be replaced continually. The rate of replacement is directly related to how hard the engine works.
Conventional coolants tolerate the addition of fresh antifreeze with many different types of corrosion protection systems. If diluted by additions of the wrong stuff, it can be easily restored without a complete change just by adding the right amount of SCAs.
The Extended Life Coolant system, introduced by ChevronTexaco and Caterpillar several years ago, is extremely reliable and straightforward, but it requires careful addition of only the right coolant. “ELC can tolerate up to 25 percent contamination,” says ChevronTexaco’s Carmen Ulabarro.
The cooling system is not a closed system, Funk says, but one subject to leakage and refilling by drivers using straight water or different types of antifreeze. This is why many fleets have continued to use the conventional system. We enlisted the help of Don Delaney, parts manager, and the other folks at the Penn Detroit Diesel-Allison distributor in Philadelphia to show us the procedure for proper conventional coolant maintenance.
Supplemental Coolant Additives can be added from a bottle or by installing a coolant filter charged with them at appropriate maintenance intervals. But there is also a much easier way.
When ELC was introduced, Penray Company responded by developing a new coolant protection system called Fill for Life. The heart of the process is a special type of SCA-containing coolant filter called a need-release filter. This type of filter is marketed by Penray as the Penray Need-Release filter, and also by Detroit Diesel under its Power Cool brand. Need-release filters stay on for a long time – in the case of the Penray unit 150,000 miles or 15 months (or 3,000 hours if you do maintenance by hours rather than miles). They are also made by several other companies (see For Further Information).
The other half of the process is the exclusive use, both for initial fill and coolant additions, of fully-formulated antifreeze meeting TMC RP-329 TYPE A specifications, which has the right dose of SCAs already in it. A number of brands of this coolant are widely available. The system becomes almost as easy to maintain as ELC, provided only the correct coolant is added. And its life can be even longer.
The big advantage of the need-release filter is that it does the job of testing the system and dosing it as required, needing only occasional routine checks in case somebody has put in the wrong stuff. Its supply of SCAs is separated from the coolant by special membranes that allow the SCAs to pass into the system only as the system chemistry changes and requires more SCAs. While it may cost several times what a standard filter with SCAs costs ($50-$70), the overall cost per mile is actually lower, and the freedom from worry about the system is priceless.
In a perfect truck where no cooling system leaks ever occurred, you would only have to replace the need-release filter every 150,000 miles, 3,000 hours or 15 months (Detroit Diesel’s hours figure is 2,000). But coolant leaks out, and some types of coolant hoses may actually allow small amounts of water to be lost from the system, resulting in a higher antifreeze concentration. You need to check out the system every six months and compensate if these things happen. Remember that if only the right TMC RP-329 TYPE A coolant is added, this job will be much easier because you will only be adjusting the antifreeze level.
For the six-month check, purchase a bottle of coolant test strips, either the two-way Penray Fill For Life brand or three-way Detroit Diesel Power Trac brand. Carefully review the directions on the label, especially test conditions.
First collect a small amount of coolant in a clean container. It’s safest to allow the engine to cool first so you won’t run the risk of burning yourself. Draining some coolant from the cock in the bottom of the radiator into a bottle is probably the easiest way to collect your sample.
If the coolant is very hot or cold, allow it to come close to room temperature. Test conditions require coolant between 50 degrees and 130 degrees F, so the strips will give accurate readings.
How to read the Detroit Diesel Power Trac 3-way strips:
How to read the Penray 2-way strips:
For both types of test strips, using a refractometer is the most precise way to read antifreeze concentration. If you have one, you may want to use it to get a more precise reading, especially if the color of the appropriate pad on the strip is right between two of the sample colors.
To use the refractometer, open up the hinged plastic cover over the light window, and then use the eyedropper supplied to get a few drops of coolant from your collection pan. Squeeze a few drops of the coolant onto the window, and then close the cover. Hold the window end of the unit toward a source of light and peer into the eyepiece. A dark line will run right across the scale and allow you to read the antifreeze concentration.
Keeping a balance
Once you know what the antifreeze concentration is, you should adjust it if necessary. The ideal concentration is 50/50 unless you live in an area where the level of protection a 50/50 mix provides, which is -34 degrees F, is not adequate. If necessary, you can use up to 60 percent concentration, which protects down to -65 degrees.
Don’t go outside this range. Using more than 60 percent will prevent the cooling system from carrying heat away from the engine’s metal parts the way it should. Using less will compromise freezing and boiling protection (allowing your cooling system to boil over too easily), and corrosion protection.
To increase the concentration, you’ll need to add straight antifreeze. To decrease it, you’ll have to add de-ionized water. You could actually use tap water from your area, provided you’ve had it tested by your antifreeze supplier and approved for use in your cooling system. Otherwise, buy de-ionized water and use that only. This is necessary because water with minerals in it will cause the SCAs to form a grit that can ruin water pump seals. They may also fail to dissolve properly and protect the system.
Once you know what the concentration is, unless it’s close to 50/50 or your desired level of freeze protection, refer to a chart like the one provided by Penray. The chart will show antifreeze concentration by percentages across the top. Each line, labeled on the left, represents a different cooling system capacity in gallons, from five to 20.
Penray’s Funk says it’s also a good idea to send your coolant to a test lab for analysis every one to two years. This will warn you if any serious problems are developing or if something has gone wrong in your testing. This would also be advisable if using ELC and there is any chance it may have been diluted with the wrong type of coolant.
For further information, please contact the following:
Caterpillar Engine Div.
www.caterpillar.com, click engines
Shell Oil Co. U.S.
Detroit Diesel Corp.
The Penray Companies
(Amalgatech does coolant analysis.)