I have Cummins DP and would like to change the antifreeze. The heater is up by the dash so the heater hoses run the length of the motorhome,how do you get the old antifreeze all out? Can someone walk me thru it?

The easiest way would be to open up all of the heater valves and put a garden hose on one side of the heater core line at the engine. This will push out the antifreeze and put in fresh water.

Make sure you get a collection jug to catch the old stuff. You don't want to be drinking that stuff thru the well water.

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quote:

Originally posted by Bill:
The easiest way would be to open up all of the heater valves and put a garden hose on one side of the heater core line at the engine. This will push out the antifreeze and put in fresh water.

Make sure you get a collection jug to catch the old stuff. You don't want to be drinking that stuff thru the well water.

Some folks prefer distilled water to hose water. Fewer minerals.

Also, be sure no animal can drink the old anti freeze. It tastes good but will cause a horrible death.

quote:

Originally posted by lu38re:
I have Cummins DP and would like to change the antifreeze. The heater is up by the dash so the heater hoses run the length of the motorhome,how do you get the old antifreeze all out? Can someone walk me thru it?

If your heater hoses haven't been changed in the last 5 years (Let me guess: they haven't) you should really change them; this, of course, will remove all the old fluid. With the engine 30-40 feet away, in the back, that's 60- 80 feet of old hose and the possibility of a multi-thousand Dollar engine repair due to a leaky or broken heater hose.
The heater supply (hot) hose (probably)leaves the engine on the driver side just in front of the oil filter and runs to the outside of the "dash" to a pull-wire actuated valve; thence over to the heater box. The return is from the heater box back to the engine, usually bundled with the supply hose. Get a handful of large (18"-24") cable ties; mark,then unclamp, the hoses; attach the new hose(s) and crawl back beneath the coach to the engine, releasing the old and re-attaching the new hoses as you go. When you reach the engine put the hoses on the proper nipples, add as much antifreeze as left the hoses, and fire it up- turn the heater on, let it warm up, check antifreeze, etc.
The heater will retain less than a pint of the old anti-freeze - not a significant amount- which will mix with the new. If you wish to replace ALL, just run water through it with the dash hoses disconnected (as suggested above)
If you re-attach the hoses as marked, they will be hooked up correctly. If you wish to know which is the supply hose before you begin, turn the heater on and feel the dash hoses to see which (of two) is the warmest.
(You may discover metal pipes in the center of the coach, with heater hoses connected to each end).
This isn't as difficult as it sounds; raising the coach to get crawl/working room is the only problem.
PS: Ask the guy at Pep Boys (AutoZone, etc) for a price on 75'; don't just order "heater hose", as you'll get a "3-foot" price -high.
Also: Replace the Cummins "coolant filter" and add the "coolant additive" when you add the new fluid.

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"You are what you drive" - Clint Eastwood

If heater hose runs the length of the coach, I would replace the hose with thick walled copper tubing (refrigerant quality). It probably is comparable in price and it will last a lot longer. Insulate it well and make sure there are no chaffing spots.

I've used schedule 80 pvc in the past and I plan on adding an additional heater soon and that is what I'll use again. Also it is very easy to install a drain/flush spigot.

My coach has the thick copper pipe from the front to the back. I agree with Eddie as this seems to be the best way to do it.

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