Flusing Coolant

[hammersley]

Can somebody tell me the correct steps to flush, well I don't have a power flusher, but the garden hose variety, and change the coolant. Also, sine my rig has 72,000 on her now and is 16 months old, should I change the thermostst? I understand they are really expensive. Are there any tricks to changing that - not sure that I even have seen where the thermostat is... ...

 

[Steve St.Laurent]

Here's an old post on how I did it:

Here's how I did mine and I got approximately 5. 5 gallons into the system, first I opened the petcock on the radiator (turn it, then pull on it a little, turn, pull, turn, pull - until it starts draining), that will drain the fluid out of the overflow bottle, once the overflow bottle is empty then take the radiator cap off. Now pull the hose connector off the top of the engine and remove the thermostat. Once it stops draining, pour distilled water into both the inside and outside holes in the thermostat hole until you see clear water flowing out of the radiator. Now pour in straight 100% coolant into those same two holes until you see coolant running out the radiator. Close the radiator petcock. Some of the water and some of the 100% coolant will be trapped in the system - should be around 50/50. Now pour in either pre-mix or mix 50% coolant with 50% distilled water in through the thermostat hole until the system is as full as you can get it. Then put the new thermostat in and the top radiator hose connector. Finish filling the radiator with the mix, close the radiator cap and then fill the overflow bottle. Run the truck until it's warmed up (so the thermostat opens) and then check the overflow bottle again.



Using this method I was able to get in approximately 5. 5 gallons (actually poured in more than that but some of it pours out) and I didn't have any problems with trapped air because I was backfilling the system from the engine to the radiator. You want to use distilled water only so you don't get mineral deposits in your coolant system.

The T-stat isn't expensive (don't remember exactly how much), and using that method it's REALLY easy to change nearly everything out!

 

[DarrellB]

Went to Cummins today and picked up a 5 gallon jug of their coolant and asked if I should use distilled water and they told me it makes no diffrence. He said that their antifreeze is made to brake down the minerals in regular tap water. He said it wouldn't hurt anything to use distilled water but it's kind of a waist. I told him I was always told to use distilled water and he showed me the back of the bucket and it says to use tap water, distilled water is not needed with this coolant. Has any one else herd this or done it without distilled water?



Big D

 

[hammersley]

Steve thanks

Couple of questions on your great answer. When you said "... . pour distilled water into both the inside and outside holes in the thermostat hole until you see clear water flowing out of the radiator" having not had the thermostat out as yet - what do you mean by the inside and outside holes? I can't quit vision what you mean. Now how does all the coolant get out of the block with this method - does it run down the bottom hose and out the radiator petcock? Also - how much is the thermostat? Thanks a million

 

[Steve St.Laurent]

When you take the thermostat out it will be very obvious, you'll just look straight down into the hole the thermostat came out of and you'll see them right there. As far as how does the coolant get out of the block, by pouring the fluids in through the thermostat hole it backfills through all the passages in the motor and the old stuff flows out through the bottom hose and out the radiator as you thought. Through www.genosgarage.com the thermostat is $17 - don't remember what it was at Cummins. It will be cheaper through Cummins than from a Dodge dealer btw. Your not getting ALL of the coolant out using this method but you are getting most of it out - enough that I wouldn't be concerned.



-Steve

 

[hammersley]

Thanks for the info - I'll check at cummins northwest today, I was told by a dodge dealer, serviec rep of all things, that the thermostat was "..... like $80. 00!" By the way, is the gasket tricky or anything? Also, folks say they put in 5 gallons - that's 20 quarts, I thought the capacity was about that - are these folks using premixed stuff? Also, I had to purchase some cooolant when on teh road, in Walla Walla Washington, and went to teh NAPA store. They had a NAPA brand that was certified by Cummins - at I think $5. 99/gallon.

 

[Steve St.Laurent]

The system capacity is supposed to be 6 gallons actually. If you read through my directions above you'll see that I used some pre-mix (you could of course mix it yourself) and some 100% coolant. The straight coolant goes in after you flush the system with water, the you pour in the straight coolant until you see it coming out of the radiator, then close the petcock and fill the remainder with pre-mix (or stuff you mixed yourself). Believe it or not there is no gasket, there is a seal on the thermostat itself, you simply pull the old one out, and once you've filled it up then you just set the new one in and bolt the housing to it - couldn't be any easier!!



-Steve

 

[hammersley]

Thanks a billion...

Steve - great poop - thanks a lot.