Procedure to replace all coolant

[Gaetan Lavoie]

I am looking for the best way to remove the coolant from my complete cooling system. I would like to get rid of as much as possible of my current coolant. I intend to use Shell Rotella Ultra ELC (OAT) as the replacement coolant.

Your help will be most appreciated.

Best Regards,

Gaetan

[GaryKD]

Hi Gaetan Lavoie,
This assumes you have a Cummins diesel. For an 06 coach, I recommend:
1. Drain the radiator using the drain cock on the bottom of the radiator.
2. I recommend you consider replacing all the rubber hose connectors. There may be 5 of these.
3. Find the lower radiator pipe. At each end will be a rubber hose about 6" long. Remove these rubber connector hoses. Warning, quite a bit of coolant will come out of the system.
4. Find the rest of the rubber connector hoses and replace all of them. If you do to lower radiator hoses first, no additional coolant will come out when the other hoses are replaced.

The reason I recommend you replace the rubber connection hoses is because the coach is 9 years old. Rubber is rubber. I would not replace the coolant in a 9 year old coach without replacing the connector hoses.

Once all is drained and replaced, add coolant via the expansion tank or top radiator opening (if it has one). Turn the dash automotive heater on full and run the engine to pump the coolant through the system.

[Mr_D]

Our DSDP is 13 model years old now. I have all new silicone coolant hoses and coolant waiting to put in. Doing some more looking I find that the small rubber hoses going to the overflow tanks are very hard even if the main hoses aren't.
Brett Wolfe has written this:

I just changed out my coolant to Caterpillar ELC and replaced all water hoses and belts. Thought I would share the experience.
To my knowledge no chassis/coach maker is using ELC—so all are “low silicate coolant for diesels” with included or added SCA. Coolant needs to be changed per manufacturer’s instructions (usually every 3 years). Additionally the SCA, pH and freeze point need to be checked on regular intervals using SCA test strips and SCA added as needed. The test strips are inexpensive and easy to use (we check the SCA concentration in all coaches at Cat RV Club Rallies). When either the time lapses (time starts when coolant installed in cooling system, NOT when purchased) or testing reveals an out-of-line conditions like pH or freeze point, it is time to change it. You can avoid all the testing and SCA adding, and go to 6 year change intervals by going to Caterpillar ELC and get better cooling system protection as well. Whichever coolant you choose, most of the steps are the same. The job is reasonably time consuming TO DO RIGHT, but low-tech.

Turn dash heater to full hot for the rest of the procedure—fan off. With the engine cold or at least cool, drain coolant. On some, there is a drain cock. On others, pull the lower radiator hose. I catch it in 2 Rubbermade 10 gallon storage bin lined with black trash sacks so I do not even get them dirty. At the end of the whole process, use a coffee can and funnel to pour old coolant into new coolant/water containers for recycling. Our city maintenance shop recycles coolant for free.

Refill cooling system with tap water. IMPORTANT: Be sure to remove any air lock from the thermostat housing. Some systems have a hose set up for this—on ours I just loosen the coolant line to the air pump and bleed the air out. Allow engine to warm up (using the cruise control to select idle speed of 1,000-1,100 speeds this up). Run for about 10 minutes at regular temp. If the temp gauge does not rise as normal, you likely have an air block and need to bleed the thermostat housing. Allow engine to cool 20-30 minutes and drain again. Repeat until the color is clear.

At this point, if this is the first coolant change on a 2-3 year old coach and you are not changing coolant brands/types, skip right to “Last rinse”. For older systems or for switching types of coolant, add a Cooling System Cleaner such as Cat Fast Acting Cooling System Cleaner 4C4611. Follow directions. Run, allow engine to cool, drain and again flush until effluent is clear. The flushing is markedly sped up by pulling off the heater hose (usually 5/8 to ¾” lines going to dash heater/motor-aid water heater, etc from the water pump. Put a hose nozzle in the hose and let it run until what comes out is clear. Run the engine to temperature at least once with tap water.

If your hoses are over 3-4 years old, this is a good time to change them as well (before last rinse). Same for thermostat(s).
Last Rinse is with distilled water. At $.62/gal at Walmart, it is silly to skip this step and leave your system full of high-mineral content water (there will be several gallons of residual water that you can not easily remove). Run engine for 10 minutes after getting to operating temperature. Cool and drain. Also drain and flush your coolant overflow container and refill with new coolant/distilled water.

Add the proper amount of Coolant CONCENTRATE (NOT PRE-DILUTE) to make 50% of cooling system capacity. My cooling system is 18 gallons, so I added 9 gallons of Caterpillar ELC CONCENTRATE (119-5150) (plus one for overflow container). Top off with distilled water to achieve your 50/50 mixture.

This is also a good time to clean the OUTSIDE of the radiator/after-cooler whether you have rear or side radiator. On rear radiator, most if the debris will be on the FRONT of the after-cooler (accessed from under the bed). On side radiators, most debris is on the outside of the after-cooler (side of coach). If it is just dirt, a hose and regular nozzle is all you need. If greasy or oily, use Joy liquid (dish washing detergent) in a spray bottle. Be SURE to rinse it off completely. You need to insure that the perimeter is as clean as the center. Ya, I know it is easier to see the center, but the fan blades "sling" the dirt to the perimeter.

Check belts while you are in there.

Probably far more detailed than most people need to do however

[danleininger]

Great post!!!

[Gaetan Lavoie]

GaryKD,

Your recommendation on replacing the rubber hoses connectors based on the age of the rubber makes sense and I will follow it.


Mr. D

This is far more than I ever expected and certainly appreciate the extend of your instructions. Now I need to see how some the info provided for a CAT engine such as "remove any air lock from the thermostat housing" and "pulling off the heater hose going to dash heater/motor-aid water heater, etc from the water pump" applies to the Cummins ILS engine.

Many thanks to both of you for all your help.

If anyone has something else to add, please feel free to jump in.


Gaetan

[Pigman1]

Mr D's instructions are right on. Just be sure to read the draining procedure closely. Some systems may have one or more drain cocks, and some have none. Pulling the lowest radiator/cooling system hose always works.

[Mr_D]

Originally Posted by Gaetan Lavoie

GaryKD,

Your recommendation on replacing the rubber hoses connectors based on the age of the rubber makes sense and I will follow it.


Mr. D

This is far more than I ever expected and certainly appreciate the extent of your instructions. Now I need to see how some the info provided for a CAT engine such as "remove any air lock from the thermostat housing" and "pulling off the heater hose going to dash heater/motor-aid water heater, etc from the water pump" applies to the Cummins ILS engine.

Many thanks to both of you for all your help.

If anyone has something else to add, please feel free to jump in.


Gaetan

Should apply for a Cummins as well, it does on our ISC except I have to be sure the motoraid gets drained and cleared of air too.

[Snomas1]

I just replaced all my heater hoses also, especially the 38" long hoses that go front to back. They are 12 yrs old! We had a rear heater hose break on I-10 last winter. It was not fun & very expensive for just a 12' hose replacement!