Locate Petcock – Changing Coolant in a Diesel Pusher

posted in: RV Repairs and Maintenance | 0

We thought that changing the coolant in our Holiday Rambler Ambassador would be no big deal. Within an hour we would have the chore done, and we would be on to other tasks. We went out to find the petcock on the radiator, two hours of searching we found nothing. We googled The Monoco Knights, the Holiday Rambler Endeavor, and some other models that used this radiator and Cummins engine combination until finally one forum suggested the petcock could be found in the frame rail.  So we tore the face plate off the back of the RV which is located directly below the over flow tank. 

We poked our head in next to the thin coolant hose and looked straight down.

 

 

The petcock is on the bottom of the radiator it is the flat thing in the light part of the picture with the threads. Turn the flat thing as to move it toward the threads to get the liquid to drain.

This what you will see when you remove the plate from under the coolant reservoir. The previous picture was zoomed in in case you needed a better picture of the petcock itself. The coolant will get all over the frame rail and all over the ground. This is too messy for anyone to deal with. So we created a more controllable exit strategy for the coolant.

 

We went to Home Depot and bought this drill driven pump for $13.00 and ice maker tubing from the appliance department. $3.00 more expense.

 

Athena lined the tubing up with the stent, pushed the tubing in while opening the valve. Once it was all the way in, she closed the valve slightly to grip the tubing.

 

She placed a 6 gallon plastic tub lined in a trash bag below the valve just in case.

 

We are moving the fluid,  leak free! 🙂

 

We ran the tubing up through the engine compartment and into the bathroom.

We placed a 5 gallon bucket with a resealable lid, and some milk jugs in the shower. If we had any spillage, the shower would be easy to clean. This also gave us a chance to look at rust or other impurities in the antifreeze. One lesson learned here, is that 4000-rpm drills will melt the drill pump. We got about 10 gallons of the antifreeze out. If we were changing coolant type we would have done several flushes with water till the green was gone. We stayed with the same coolant, so we were satisfied. Will have to buy a new pump though.

 

Type of coolant to put in? Under the parts department’s recommendation at the Albuquerque cummins dealer, we put in Zeerex Green, which accepts SCA. Our Manual seemed ok with that but they want a pound of SCA added with the new coolant. We have been looking for SCA, now for about a month. NAPA Truck and other parts stores look at us like we have lost our marbles. We may do the job again, but flush the cooling system, upgrading to the new filtered system and OAT coolants.