Coolant Change and short hose replacement 3rd gen Cummins

In this article I'll discuss a back yard coolant change / flush, plus how to change out the short piece of heater hose that returns coolant from the heater core to the water pump. This is the hose that has a tendency to leak in the fall. Supplies needed for the jobs. 4 gallons of coolant. I used Zerex G05 H.O.A.T coolant which is the only coolant I have found that meets our engines requirements other then the Mopar coolant. I also used 13 gallons of distilled water. A new drain valve from Chrysler. I didn't need this but I have had bad luck with this type valve before and didn't want to take a chance. My dealer charged < $7 for this, so it was good insurance.

Valve P/N

Valve itself.

New Hose P/N

New clamps for hose P/N (2 required)

First thing was to drain the old coolant. I did this with the nose of the truck facing down hill (I thought I might get more out this way) and a cold engine. You need to turn the valve counterclockwise and pull a little on the valve, mine kinda stuck a little, but with a little pulling it came out and started draining.

Keep the radiator cap in place and tight while you first drain the rad.

If your rad cap is functioning properly it should drain the overflow tank.

If it doesn't drain the overflow either your rad cap needs replacing or you don't have it on and tight.

Once drained I got about 5+ gallons out.

Now it was time to remove the old hose, that I was going to replace. I fought this thing for quite a while trying to reach it and get it apart.

First remove the clamps. Then remove the bolt holding the bottom rigid pipe to the block using a 13mm socket and whatever combination of extensions to reach it. I don't have a good picture with the bolt in place, but in the pic below you can see a bracket attached to the pipe with the hole the bolt went through and the threaded hole in the block that the assembly attached to.

Next I prepared the new piece of hose with some reflective tape and got a clamp ready to install. The tape was a waste of time because as soon as I put the hose over the pipe the tape came off. Dodge says that the tape is not required anyway.

Here is a pic of the new hose (left) next to the old hose (right).

Next I used some vise grips to hold the clamp open and in place on the top pipe.

Now I slipped the new hose over the top pipe using a little spit to lube the hose so it slid on easy. There was a small stop welded to the the top pipe. Don't push it on to forcefully or it will go over the stop and it is a real PITA to get it back down to the right position. Once in position slide the clamp in place and release the vise grips.

Next I opened another clamp with my trusty vise grips and put it on the bottom pipe. Then lubed the hose again and pushed the bottom pipe all the way into the open end of the hose. Then positioned and released the clamp. Then reinstalled the bolt that holds the assembly to the block.

Now we were ready to complete the flush and refill procedure.

First close the drain.

Then fill the rad with distilled water.

I found out that even though our engines are supposed to be self venting that it only took 1.5 gallons to fill. eek

Since I knew I took 5+ gallons out. I decided to vent the system myself by removing the heater core hose to let the air out. I did this by disconnecting the hose at my shut off valve (A/C Mod), but you could just as easily remove the hose at the fitting below in the pic if you don't have a shut off valve. This worked out good, because when it got actually full (about 4.5 gallons) a little old coolant came out of the hose ends. Once this happened I buttoned up the heater hose connection and filled the overflow tank with distilled water too.

Now I started it up and let it idle for a few minutes and then drove to the store to pick up a few thing. This ride got the engine and coolant up to operating temps and made sure the cooling system circulated the water throughout the system. Then I came home and after a little cool off time, I completely drained the system again. I refilled the system with distilled water again following my procedure above, and did a warm up drive to go pick up supper. After eating the system was cool enough to drain again. This drain came out clear and no traces of old coolant could be detected in the catch basin, so I was satisfied that I had cleaned it out good.

Next it was time to refill with a 50% coolant, 50% distilled water mixture. Since our cooling systems hold 7.375 gallons total according to the shop manual I assumed that I already had 2.375 gallons of distilled water in the system. So first thing added was 2.375 gallons of straight coolant (not premix). Then since I had lots of empty jugs around I premixed at a 50 / 50 ratio coolant with distilled water and topped off the rad using the heater hose trick again to vent the system. I then filled the overflow bottle with the 50/50 mix to a little above the full line on the tank. I took the truck out for a ride to get it up to temp, and then let it cool down over night. The next morning I had to add about a quart or so to the overflow tank as it still must of had a little air trapped and worked it way out. I drove the truck around the following day and the morning after that it took about 1 more quart. Now it is holding it's level and all is well.

BTW, the Zerex coolant is almost clear, it just has a very light yellow color to it, but it can be seen in the overflow bottle with no trouble.