PMF - Preventive Maintenance Flush (Cooling System Flush)

PROBLEM 

Natural Gas Compression Engine plugged with a substance that was solid, semi-solid, or gelatinous in consistency depending on where it was removed from in the cooler.

The engine had recently been serviced using an OEM Radiator Flush, followed by the addition of new coolant, and a cooling system supplement. At some point after this service, the engine developed an overheating problem. After collection of three samples and a borescope inspection, It was determined that the cooler was plugged with a foreign substance requiring the replacement of the radiator and antifreeze. After our sample analysis on the source of the substance that restricted coolant flow in the radiator, we determined our results were consistent with what is known as “Silicate Drop Out”.

ENGINE COOLANT 

Nearly all modern coolants used in all types of engines in North America use silicates and silicones to inhibit corrosion of the components. Most antifreeze used in North America is Ethylene Glycol based. Corrosion inhibition for engine and cooling system components that are in contact with coolant (heads, intakes, radiator, e.g.) is generally provided by adding alkali metal silicates and silicone to the coolant.

These silicates under certain circumstances:

• High coolant temperature

• Coolant with a depleted additive package (worn out coolant)

• Hard water (water mixed with coolant)

• Over concentration of coolant (not enough water)

These circumstances have a tendency towards “polymerization”, which can cause “silicate dropout” or “precipitation” which can lead to gelation of the silicates in the coolant.

When this happens, the interior of the cooling system and engine are coated with a gelatinous material that significantly reduces heat transfer and slows or even stops the circulation of coolant within the system.

This reduction in heat transfer and restriction of coolant flow can then raise the temperature of the fluid to a point where this gelatinized precipitant can turn semi-solid or solid in the cooling system.

CONCLUSION

This problem pre-existed the initial service.

• The problem is the result of “Silicate Drop

Out”.

• The Silicate Drop Out problem is not the result of, or caused by using either the OEM radiator flush or cooling system supplement products.

• The problem requiring replacement of the radiator would have occurred with no service, with a service that did not include a proper flush or supplement products, or as happened with the use of those products.

• The most likely cause of this condition is the age of the coolant is failure to properly flush out deposits building up over multiple coolant changes, and the temperatures that this particular engine’s cooling system was subjected to.

• The unknown mix concentration and the “hardness” of the mix water are also unknowns which may have caused or aggravated the condition.

RECOMMENDATIONS

The normal testing process of checking the pH level of the coolant, while a good measure of most coolant conditions, will not show “Silicate Drop Out”.

Because of this potential problem and the extreme heat load placed on engine coolant in heavy duty engines, the coolant needs to be checked and replaced much more often than in the past.

The cooling system should be flushed of any residual buildup from silicate dropout, burnt glycol, and carbon deposits.

BEST PRACTICE 

The fin-fan cooler tubes should be cleaned externally annually, semi-annually if needed. (Every 1 millimeter of dirt is a 10% or more loss in efficiency)

• Coolant should be tested annually, and replaced every two years regardless of hours.

• In some extreme conditions adding a coolant supplement every year is advised.

• When coolant is replaced, the system should be flushed using the highest quality flush agent to ensure removal of residual silicate drop out performed with proper equipment by trained professional.

• Extra care should be taken to inspect the visible areas of the cooling systems for buildup of any material. This includes the Filler neck, Thermostat housing, water pump, and Surge tank.

• When the new coolant is installed, if not Extended Life Coolant, the addition of a cooling system supplement will provide a much higher level of protection and extend the life of the coolant.

• The mix concentration of water to coolant must be carefully monitored to assure it meets coolant manufactures recommendations.

• The hardness of the water used to mix with the coolant should be checked and addressed if needed. (purchasing pre-mixed coolant in bulk may prove to be a prudent solution).

• Thermostats should be replaced regularly according to manufacturers preventive maintenance schedule

DETERMINATION 

The very low level of silicone found in the fluid supports the conclusion that the original coolant was “worn out” and silicate dropout had already occurred in this cooling system.

PMF - Preventive Maintenance Flush

STEP 1

1. Thoroughly mix 1:1 - 1 part PMF to 1 part deionized water
2. Record water pump pressure and all temps.
3. Shutdown/Remove Surge/Day Tank Cap.
4. Install 1” ball valve on each side of block underneath rail.
5. Drain all old coolant.
6. Fill with Flush until overflow from Surge/Day Tank. (Dilution 1:1).
7. Start/Run Unit loaded at full speed with flush 7 – 14 days (10 Days Optimal)

STEP 2

1. Shutdown/Remove Surge/Day Tank Cap.
2. Power wash Surge/Day Tank with STH - Surge Tank Hose (while still hot and full). Let particles overflow. (15-20 min)
3. Drain Flush via ball valve on each side of block underneath rail. (dispose as you would old coolant)
4. *If Rust Is Present
5. *Fill with deionized water until overflow from Surge/Day Tank.
6. *Start/Run Unit loaded at full speed with flush until up to temp and thermostats open.
7. *Drain Unit
8. *Fill with RRF - Rust Removal  Flush and run 2 hours at full temp.
9. *Drain Flush (dispose as you would old coolant)
10. Fill with deionized water until overflow from Surge/Day Tank.
11. Start/Run Unit loaded at full speed with flush until up to temp and thermostats open.
12. Continue to pump in water until overflow at Surge/Day Tank before opening ball valves. (2 x volume) overflow until clean.
13. Inspect water pump and replace thermostats.
14. Drain Unit / Fill with New Coolant*

*(Best Practice) Do not leave or run with water only. 

Fill with coolant mix and 3%  CRI – Corrosion Rust Inhibitor

PMF - Preventive Maintenance Flush - SDS

All SDS