I have been doing some research on coolant maintenance lately. There has been much talk or controversy of whether you can run extended life coolants or ELCs in the Ford psd. While I have yet to see or hear of the problems associated with it's use, the warnings are there. For instance, Cummins states "Cummins Engine Company announced in a memo dated July 16, 1999, that these materials based on Organic Acid Technology (OAT) are not compatible with their engines. Cummins is reporting that these long life antifreezes cause degradation of silicone seals in their engines after 80,000 to 100,000 miles of service. Cummins, therefore, is not recommending the use of long life coolants in their engines." See Hastings Filters We saw recently where Navistar stated that they were endorsing the use of Texaco ELCs, however, Ford denied it's possible use and still warns of it for the same reasons stated by Cummins.

Now, here's where it gets interesting. ELCs and conventional SCA based coolants are not to be mixed. The SCAs are not to be added at any time to an ELC. This is not a proper procedure for this type of coolant. See quote from Baldwin Filters "While coolants using current SCAs require the SCA level to be replenished on a routine basis, coolants using extended life antifreeze require inhibitor package replenishment only once during its service life. The inhibitor additive for extended life antifreeze is not an SCA style package. Only a special formulation additive package is to be used with extended life antifreezes. Neither the current formulation SCA package or the special extended life package are to be substituted for each other at any time."

And from Shell Corp. quote "Do not add any supplemental coolant additive in either filter or liquid form"

And then from Penray "Supplemental Coolant Additive (SCA) for Fully-Formulated Coolant: Fully formulated coolants do not require, and should not receive, an initial charge of SCA. Plain water systems do need to be treated. The proper dosage for plain water coolant is 5.0 percent by volume. Check the nitrite concentration at regular intervals (3 months, 20,000 miles or 300 hours, whichever comes first) with a Penray test strip. Additional SCA must be added to the coolant if it becomes diluted, as indicated by a nitrite concentration less than or equal to 1,200 PPM. If the nitrite concentration is greater than 1,200 PPM, and the system is equipped with a Penray Need-Release filter, do not add additional Pencool SCA."


And here from Caterpillar is more great info on this.

Now, with this in mind and the fact that ELCs have a life expectancy of 300-600,000 miles, it would seem to be the coolant of choice. But, we are stuck with the fact that ELCs are an acid based coolant and require the engine to be built for it.

Now, SCAs are actually a suspended solid that coats the walls to act as a sacrificial liner. See Carpentractor's Site Actually, his site is the one that got me looking further into this. I find it hard to believe that the proper maintenance of our trucks is to add an abrasive particle to the coolant system to stop the wear of cavitation, but in turn wear away at the water pumps, seals, and hoses. This seems to be very prehistoric in the days of technology. We can build these magnificent trucks and engines and we are still stuck with such a crude method of protecting the coolant system? I have found one product that claims to have that beat RMI-25 , but can I really don't have long term personal experience with it. I have many testimonials, but I believe it is better than SCAs.

Now, the other option I have come to be aware of is Evans Waterless Coolant which claims to be a lifetime coolant, but is not an ELC(acid based). They are a PG based coolant that is designed to be run at 100%. They claim no need for any type of SCAs or any maintenance of any kind. In fact, they are sending me some literature claiming a Detroit diesel truck going 500,000 miles with no SCAs or maintenance of any kind to the coolant system. This was done for a magazine. Sorry, don't have more details yet. When they pulled down the engine, there was no sign of cavitation present.

What I am getting at, is it seems we are simply addressing the wrong part of cavitation with our current form of maintenance. We are simply trying to stop the erosion from cavitation, instead of dealing with the cavitation itself. The PG type coolants and the ELCs seem to have accomplished this. IOW's they stopped the problem, instead of dealing only with the consequences.

 All this got me to look into all the types of coolants I could find, in at least general categories. The following are the results of my findings.

Ethylene Glycol is the standard coolant used in engines for years from gasoline to diesel. I will not go into depth here due to the fact, I did this research to find an acceptable "better" solution. This method has been used for many years. It's accepted, but it has many flaws. In diesels, I explained those downsides earlier. In gasoline engines, as long as you changed it frequently, it performed it's job, but it still lacked many properties that make it ideal. Since so many people ignore thoer coolant systems, I feel this system has room for improvement.

But, to explain EG coolants. EG has a standard mix rate of 50%. You must add 50% water to this mix. The coolant and your additives, (in the case of diesels) are fighting the properties of water. Why are we still using it? You might say, why don't we use 100% EG? Anything over a 60% -70% rate, the freeze protection is eliminated. It needs water to lower the freezing point. A 50% EG/water mix has a boiling point of approximately 220, so you must pressurize the system to keep the water from boiling and it hence raises the boiling point to about 270 degrees under a 16lb cap.

In any vehicle, diesel or gasoline powered, the effects of water are widely known, but dismissed as normal. Rust, corrosion, and scale are all results of water. Without water , you have no source for these things. Another aspect is "hot spots". This is caused by localized boiling of water in the system where heat is raised above the waters boiling point. When this happens, heat transfer is stopped at this point and you have scuffing of piston skirts, etc. This localized boiling cause air to be trapped at the hot spot leaving that area to be void of any coolant and thus damage is eminent.

Dexcool is a trademark name owned by Chevrolet to designate a type of coolant classified as ELCs or extended life coolants. These are a ethylene glycol based coolant with combination of sebacic acid and 2-ethylhexanoic acid supplemented with tolyltriazole. See Penray FAQ for more technical information on Dexcool.

There have been many discussions on the topic of how good this type of coolant is and Chevrolet has had numerous complaints on forums and techs I have talked to swear off the stuff. This caused me to look further.

Complaints of this coolant have been severe blockage of water passageways and radiators. Here was an e-mail sent to a member on a chevy forum. This came from the technical dept.

"There are two possible causes for a corrosion build-up in the cooling
system:

1) If the level of coolant in the radiator is allowed to drop below the
minimum level for an extended period of time, then there is an air space in
the top of the radiator and the top of the engine block. These areas do not
receive protection against corrosion--only hot steam. The corrosion can
break loose and will appear as a build-up in the antifreeze/coolant.

2) The radiator was topped off with a conventional green antifreeze/coolant
(AFC). These green AFC contain silicate corrosion inhibitors that have a
tendency to gel and have to be changed more often than Dex-Cool AFC. This
could have occurred when you had the oil changed, as establishments that do
this service often top off the cooling system.

General Motors has issued a Service Bulletin to its dealers concerning
cooling system problems with Dex-Cool (Bulletin No. 99-06-02-012). General
Motors attributes the problems encountered to vehicles "which may have been
operated for extended periods of time with a low coolant level (usually in
excess of 20,000 miles) may be susceptible to the formation of a rust-like
material in the coolant system". This Service Bulletin requests the dealer
to perform a flush on the cooling system and replace the thermostat.

If you keep the cooling system full and the overflow bottle at the correct
level, then you should have no corrosion build-up.

Our family has a 1998 Chey Blazer. I have maintained the coolant levels
since it was new and periodically take off the radiator cap (when the system
is cold) and look inside the radiator with a flashlight. It is crystal clear
with the orange color and looks like a new system. The overflow bottle is
also crystal clear with the orange color.

To change a system from a conventional coolant to Dex-Cool the system should
be thoroughly flushed with water. In order get the extended life, greater
than 90% of the antifreeze should be Dex-Cool. The system should be blended
with distilled or deionized water to a -34F freezing point for a 50/50
concentration by volume. The 50/50 blend ensures that there is enough
corrosion inhibitors to protect the system. We do not recommend going over
60% antifreeze concentrations.

If the system is plugged (generally the heater core plugs first), a water
flush may not be sufficient. General Motors recommends using the Prestone
Flush and Fill Kit along with Prestone Heavy Duty Cooling System Cleaner.
They also recommend changing the thermostat if the system is plugged.

This was further backed up by a presentation by Texaco and GM where they explained the problems in depth. See "Bare All" about DEX-COOL® Evidently, Dexcool does not like air in the system or getting topped of with standard coolant, which happens frequently at lube shops.

So, if you use Dexcool, best results are had if you carry a gallon of coolant with you to give to the lube mechanic to top off correctly, check your coolant caps frequently for corrosion, and keep it full, some say even fill it to the hot line when cold.

 

Propylene Glycol is another form of coolant, and is being commonly misunderstood and thrown into the category of ELCs. This simply is wrong. As I stated earlier, ELCs are actually EG based coolants with organic acid compounds mixed in. PGs are totally different.

Now, PGs were initially touted as non toxic. Now, due to pressures on them by the EPA and FDA, they must say "essentially non-toxic". This because, even though PG is actually safe to drink in pure form, the additives that make it a coolant are toxic. PGs are actually used in coffee beans as a preservative, in some make-ups, etc. In pure form, it is very safe and biodegradable.

There are many makers of PG coolants, however, one has stepped up to the plate, so to say, and stated just how they reccommend the maintenance to be done. For this reason, I will only concentrate my focus on them. The others give no real info as to the benefits other than environmental. They may feel they have a good product, but lack the technical experience in it to explain just how to maintain it and how long to leave it in. This company is Evans . I suspect they may even make most of the other company's fluids, however I have no info on this. Their recommondations for fill and drains are 500,000 miles for a diesel, and lifetime for gasoline engines, regardless of use. This also with not having to add any SCAs at any time.

This company owns a patent on this fluid and it's magic is a "waterless" solution. This coolant is to be mixed with no water at all. This is where the other coolants have failed. We are trying to deal with the shortcomings of water. Rust, cavitation, scale, overheating, are all properties that water give us. PG mixed at a rate of 100% gives a boiling point of 400 degrees at 7psi, where a 50/50 mix of EG and water is about 270 degrees at 16psi. You can actually run this type at full temp with no cap and it won't boil out! So, you can see the advantage. No water to rust, less pressure on the system, no maintenance, and essentially a lifetime coolant.

The disadvantages? More expensive, less available, more widely misunderstood. But, the availability is it's biggest problem. You can mix EG with it if you loose a hose, but you would have to drain it again and start all over to get the proper protection.

This is the type coolant I have decided to install in my truck. I believe this will be the very best protection that I could accomplish with little to no worries about it. Best thing, I don't have to play chemist every couple months to make sure everything is still in balance.