Flushing Coolant System

[coarsegoldgg]

Our transmission cooler burst inside our radiator and filled the coolant with transmission fluid. The radiator is being repaired but nobody seems to know what to do to flush the rest of the system. We have a 370hp Cummins/Allison transmission drive train. Is there something that can be done prior to reinstalling the radiator and then after installation to make sure the system is clean before we add coolant again?

Thanks

George

Stuck in Canada

[coarsegoldgg]

Funny that nobody had a comment on this problem seeing as how I have met 3 people in the last week with the same problem. Here's what we did in case any of you are faced with the same issue. We had the radiator repair which takes care of it. At the same time we mixed up Dawn dish detergent in hot water and fush out the cooling system the best we could before it reinstalled. After installation we filled the entire system with Dawn soapy water and ran it for about 20 minutes and then drained it. Refilled with new soapy water and drove it down the highway to get up to temperature and then drained it another time. Each time less and less crud came out. We then filled the system with coolant and will drive it for a week or so and then drain it out yet again. Hopefully we will eventually get it all out. The nice thing is the crud collect in the overflow tank each time. Maybe I'll try overfilling it to remove the stuff without draining the entire system.

[Spike45]

Our transmission cooler burst inside our radiator and filled the coolant with transmission fluid. The radiator is being repaired but nobody seems to know what to do to flush the rest of the system. We have a 370hp Cummins/Allison transmission drive train. Is there something that can be done prior to reinstalling the radiator and then after installation to make sure the system is clean before we add coolant again?

Thanks

George

Stuck in Canada

Flushing an oil contaminated cooling system is best accomplished with use of specific cleaners designed to remove oil contamination in an aqueous coolant system (coolant composed of water and antifreeze). Oil in the coolant interferes with the function of the SCA additive that protects the liners or parent bore, coolant side against cavitation pitting. At least one HD cooling system cleaner is available, Fleetguard Restore Cooling System Cleaner. For simplicity, it is the fastest at removal of lube oil from cooling systems with minimum flush cycles. Caterpillar also has a cooling system cleaner. I have no experience with it as to ability to remove more than just scale, rust, and corrosion. If it removes oil as well, that will be a plus. Some have recommended here and other forums to flush the cooling system using liquid dish detergents. While they work to some degree, they do create some other issues.

The main problem with any liquid detergent is that it creates a lot of foam. While flushing an engine you need to get the cooling system hot. Hot engines do not need foamy coolant especially in the cylinder head area. Proper flushing requires the engine to get up to operating temperature such that the thermostat will open and allow free circulation of the flush coolant to clean the radiator as well as the engine. Since most draining of these systems is a slow process, the water/detergent method usually redeposits oil onto the cylinder walls and other surfaces during the very slow draining process. This method requires many flushes to remove the oil completely, if you can ever get it completely out. If you must use a detergent cleaning process do the following:

Drain the contaminated coolant from the engine.

Fill the system with plain water and run until the engine gets hot and has radiator circulation.

Drain the flush water from the engine as quickly as possible (see note below on draining)

Using dish washer detergent powder (non-sudsing) mix 1/2 large box of powder into the system filled with water.

Leave the radiator cap OFF. This will speed the draining processes later.

Run the engine at a fast idle and may need to cover the radiator to achieve an operating temperature of about 200F

Run for an hour at temp and speed. Shut the engine down. Drain flushing agent quickly.

Repeat again with the second half box of powdered cleaner.

Note about fast draining: Even with this much more robust powdered cleaner, fast removal of the flushing fluid is necessary as even some oil can separate and adhere to the internal engine surfaces. If you are brave enough, remove the lower radiator hose clamps and remove the bottom radiator hose. This will drain the engine quickly. Loosen the hose form the connecting pipes after the first draining of the oily coolant before starting the cleaning process. Only tighten those hose clamps sufficiently to avoid major leakage. Use a 5/16" nut driver or 1/4" drive ratchet and 5/16" socket and extension for loosening the worm drive hose clamp.

After cleaning, re-tighten the bottom radiator hose clamps. I should add that if the coolant hose on your MH is NOT silicon rubber coolant hose, replace that hose and the others as they are likely made of EPDM rubber as it will be damaged by lube oil in the coolant. Most EPDM coolant hose has a black liner. Silicon rubber hose has a burnt orange hose liner color. Silicon rubber will not be phased by oily coolant. Instead, it has its own problems when you use it with CAT ELC and other similar OAT coolants!

Refill the cooling system with new coolant meeting at least the ASTM D6210 specifications. If you are refilling a Caterpillar engine and desire to use CAT ELC, it is best not to use silicon rubber hose as it will have its liner degraded causing it to become heavily "checkered" with surface cracks.

To aid in removing air from your engine while refilling the coolant, pour it no faster than three gallons per minute. Venting of air from the engine can be facilitated by loosening or removing a temperature sensor in the thermostat area (if equipped). When air quits bubbling out of the sensor port, the engine is purged of air. Run the engine at a fast idle for a half hour should remove the remaining air from the engine and coach plumbing circuits. If you have an engine equipped with EGR, special circumstances may need to be followed to be certain the EGR cooler is purged of air. Failure to correctly purge air from an EGR cooler WILL result in cracks and coolant getting into the engine oil plus the megabucks to replace that cracked EGR cooler. If you have doubts about this process take it to a repair shop.

[kaynehopkin]

Is your automobile's radiator able to conquer the summertime temperature? Don’t let the lengthy, hot summer beat down your automobile's radiator. Deposit accumulation can block the air conditioning and lead to motor overheating that leaves you dead on the highway. Knowing how to clean your radiator and replace the antifreeze before that hot summer trip will save you cash. Check this out: How to flush your radiator.

[wolfe10]

Is your automobile's radiator able to conquer the summertime temperature? Don’t let the lengthy, hot summer beat down your automobile's radiator. Deposit accumulation can block the air conditioning and lead to motor overheating that leaves you dead on the highway. Knowing how to clean your radiator and replace the antifreeze before that hot summer trip will save you cash. Check this out: How to flush your radiator.

Welcome to the FMCA Forum. As I am sure you are aware, there are significant differences between automotive and gas coach coolants and those used in diesel applications. Said another way, the Prestone you get at Walmart is not approved by any diesel engine manufacturer. Please refer to your engine owners manual for Mil Specs of acceptable coolants if you have a diesel.

Brett