Coolant change, '06 Inspire, 36', Cat C9
After MUCH research and more frustration, I have elected to share my experience - TOTAL COOLANT CHANGE. I'll be as brief as I can. My total coolant capacity is unconfirmed in spite of multiple searches, but around 24 gallons??? I installed a flush-and-fill tee, with a cap, (~$5 and a SIMPLE install) in the HEATER HOSE just behind the front right "bumper" to drain the heater as best I could. On my rig, the lower RADIATOR HOSE becomes a metal tube just behind the side mounted radiator in which there is a plug to drain the engine coolant. I changed the engine thermostats - there are two - easily accessible on the upper rear of the C9, that cost less than $60 for both and the gasket. (There are good forum posts about that procedure.) My Denver Cat dealer UPS'd them - no delivery cost. My theory is that the smaller opens first and dribbles coolant to the heater to warm the driver(s), then the larger one opens when that huge engine needs major cooling through the radiator.
I drained both ends (the old coolant looked pretty good), refilled with water and a packet of dishwasher soap and ran the motor (at 1200 rpm with the cruise control!) with the front heater ON until the heater fan blew warm air - about 15 minutes, then 15 minutes more. Repeated twice with only water to get it clear. I used my Colorado well water that has 2 grains mineral, but many suggest using distilled.
I put in 12 gallons of Rotella ELC concentrate - I didn't want to add the 50/50 mix that would be diluted all the more by water in the rig I couldn't drain. Then gradually as the engine ran, I added the 4 gallons(!!) of water it took to bring the level to the MARK that was ½ way up the reservoir. I ran the engine, with the cabin heater on, for 30 minutes. Checking the strength of the resulting coolant: all 5 balls in the tester FLOATED --> good to BELOW -40° F! Conclusion: my coolant capacity is much less than 24 gallons, even if you count the total reservoir capacity.
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