Cooling system flush and fill process

[Brian Diehl]

I'm going to flush and replace my coolant this year.  So, for those who have been there and done that .. I'm looking for ideas to make the process easier and faster.

1)  Drain coolant
2)  R&R thermostats  (going with 160 degree stats)
3)  Flush with what?  How much?  How long?  Include heater cores as well?
4)  Drain again
5)  Fill with fresh coolant and distilled water
6)  Add DD SCA additive

Can I use regular green automobile coolant with the addition of the SCAs?

Any special procedures to purge air from the system?  I know about the air release valve on the main heater core and the release valve on the cross-over tube on the engine and on the left rear thermostat housing.

While I have the coolant drained I'm going to hook in my webasto.  Where should I connect the suction and return lines to ensure maximum circulation through the engine without wasting heat in the heater cores and radiators?

Thanks for any ideas.

FYI:  6v92/HT754 in a 1985 MCI 96A3

[Melbo]

When I drained my cooling system (what a mess) I had a bad mix of anti freeze of one kind or another. I recycled the stuff I took out and then I used an additive for automotive coolant flushing with plain tap water which I did not recycle. I had both radiators recored and replaced all the seals etc and then I went to get antifreeze from stewart and stevenson and spoke with the shop manager there who had serviced my coach and checked it out right after I bought it. He recommened the detriot desiel premixed antifreeze (of course he would it is the most expensive). I asked a bunch of questions and what it came down to according to him was use the good stuff and don't worry about having to check the mix and ph etc. or use the less expensive stuff and you have to check it and balance the mix etc. I may be gullible but I spent the extra couple of dollars and so far everything seems to just fine. Just a quick outline of my experience draining and flushing my system.

Melbo

[Brian Diehl]

Thanks Melbo,
Question:  Did you just let the flush drain on the ground?  Is that okay to do?

[Melbo]

Brian

It was a two step process that was designed for a much smaller system than I have so I used two containers of the first part and then I opened it up and let it drain til it ran clear and then used the second half of the mix it neutralized the first half and I ran it til it came back up to temp and then with a hose in the fill I opened the drain again til it ran clear. I just did that to be sure all the anti freeze was out before I pulled the radiators. I couldn't figure out how to get rid of water in that quanitity with a little alkali or acid in it. So yes I let run away. I'm trying to remember how much it took to fill the system. Seems like it was thirty gallons or more.

Melbo

[Buffalo SpaceShip]

Brian D.:

Before you do anything, take a look at DD's coolant specs.: http://www.detroitdiesel.com/Public/brochures/7SE298.pdf

Usually automotive coolants are a bad choice because of their phosphates and poor mix of additives. DD's Power Cool Plus is maketed as a 600,000 mile (!) coolant. Might be worth some extra $ to never have to change your coolant again.

Whatever you do, don't flush your coolant or flush-back into the street, because it's highly poisonous and will end up in your local waterways. Most municipalities, if they don't have a haz. mat. fluids recycling program can at least point you into the direction of a fluids recycler.

HTH,
Brian B.

[edvanland]

Anti freeze will KILL animals.  Be sure you wash down any spills with a lot of water.  Again I repeat ANTI FREEZE WILL KILL YOUR PETS.
ED MCI 7

[DrivingMissLazy]

Strongly suggest you do not go to 160 degree thermostats as planned. The DD really needs to be run in the 180 degree range.
Richard

[HighTechRedneck]

As Ed pointed out, antifreeze is lethal to animals when they drink it. I realize so are a lot of other vehicular fluids that have a tendancy to leak on the ground.  But what makes antifreeze worse is that many animals (i.e. cats and dogs) like the taste of it so they are drawn to it.

[Melbo]

Yes Yes Yes

Be sure to catch all of the anitfreeze and get it to a recycle company or center.

It has a sweet taste to it and animals love it and it will kill them.

Melbo

[buswarrior]

Hello Brian.

If you are interested, DD has its own 2 part coolant system flush.

Comes in two plastic bottles. One an acid, the other a neutralizer.

Get it from your DD dealer.

For dealing with the drainings, you want to have a barrel that you can pour the stuff into and then take it off to the recycle.

Draining the neutralizer into the same barrel will fix the acid from the first draining.

The written directions are pretty thorough, though my DD folks suggested that the powder mixes much better with hot water. You want it completely dissolved before pouring it into the system.

And once you drain the 2nd part, flush and flush and flush and run it some more and flush, with water to get it all out.

Get all the valves rigged to be open. Heater cores are just as clogged with green goo etc as the radiators. You want it all out!!

As already mentioned, it is highly recommended that you put in the right antifreeze, name brand or otherwise, it needs to be for heavy duty diesel engines, not cars.

It is popular in the commercial fleets to have a coolant filter plumbed into the system somewhere. This device looks like a spin-on filter, but really isn't a filter, it introduces the additives as they are needed. The lines in and out are only small piping.

While you have it drained, as well as thermostats, one might consider the cheap insurance of replacing the alarmstats with fresh ones. Always nice to know it's overheating, eh?

happy coaching!
buswarrior

[Brian Diehl]

Thanks everyone for the feedback.

Buswarrior -- My alarmstats are only 2 years old so I don't think they need to be replaced.

Richard -- Why not do 160 thermostats?  I currently have 160s in the bus and wonder what difference having 180s would make?

Also seams people prefer the DD coolant...  I'll have to price that at both our local DD and C&J Bus repair.

[buswarrior]

Hello Brian.

I agree, your alarmstats are still young, and you know their vintage.

happy coaching!
buswarrior

[Brian Diehl]

Any special procedures to purge air from the system other than the 3 release vavles mentioned?

[Melbo]

Brian

I don't remember any special procedure I went through to purge the air other than topping off as necessary as the level dropped in the "holding" tank at the back. I remember adding a gallon or a half gallon a couple of times and now I havn't had to add any more.

Melbo

[Paso One]

Brian  I have a circulation heater on my bus that takes the coolant from the lower head (on the front closest to the radiator) and empty's to the upper plug on the back of the other head. ( top right )
Note: standing at the back looking in )  6V71  When this is plugged in the electric circulation heater circulates the coolant thru out the whole block and is warm to the touch anywhere on the block.

I plan to tap the webasto into the same locations Lower left for the return line  upper right for the suction side of the webasto. Hope  this all makes sense if not I'll try again. paul