Changing Engine Coolant VP D3-150

[dclagett]

I am interested in how others change their VP D3-150 engine coolant which includes the cabin heater and water heater. The VP maintenance schedule suggests changing it every 48 months. The first time I changed the coolant I had the cabin/water heaters turned off due to a leak around the hose connections on the water heater which are extremely hard to get at. I plan to fix the leak this spring and would like to change the coolant in the whole system.

On the D3-150 there is only 1 petcock on the engine heat exchanger for draining the coolant. The last time I changed the coolant I only was able to get about 1.7 gallons out, having the cabin/water heaters not in the system. The engine itself is supposed to have 2.3 gallons, so I was not able to drain all coolant out of the engine. When I reconnect the heaters into the system I am not sure the best way to remove the coolant since the hoses that connect the heaters are lower than the engine petcock. Also the feeder hose from the engine to the heaters is very difficult to get at without some disassembly of engine components.

One approach I was thinking about is to change the coolant every 12 months (instead of 48 months) out of the engine petcock removing as much as I can. This would provide almost 2 gallons of fresh coolant to the system every year. I am not sure the total coolant capacity of the entire system and if this approach would maintain sufficient fresh coolant to keep the system healthy.

Any thoughts would be appreciated.

 

[S. Todd]

Your plan to change what you get out through the petcock once per year is what we did for the 6 seasons we owned our R25SC. That way if there was any of the original fluid in the system after 48 months it was well diluted with fresher antifreeze.

 

[Kevin Lamont]

I am interested in how others change their VP D3-150 engine coolant which includes the cabin heater and water heater. The VP maintenance schedule suggests changing it every 48 months. The first time I changed the coolant I had the cabin/water heaters turned off due to a leak around the hose connections on the water heater which are extremely hard to get at. I plan to fix the leak this spring and would like to change the coolant in the whole system.

On the D3-150 there is only 1 petcock on the engine heat exchanger for draining the coolant. The last time I changed the coolant I only was able to get about 1.7 gallons out, having the cabin/water heaters not in the system. The engine itself is supposed to have 2.3 gallons, so I was not able to drain all coolant out of the engine. When I reconnect the heaters into the system I am not sure the best way to remove the coolant since the hoses that connect the heaters are lower than the engine petcock. Also the feeder hose from the engine to the heaters is very difficult to get at without some disassembly of engine components.

One approach I was thinking about is to change the coolant every 12 months (instead of 48 months) out of the engine petcock removing as much as I can. This would provide almost 2 gallons of fresh coolant to the system every year. I am not sure the total coolant capacity of the entire system and if this approach would maintain sufficient fresh coolant to keep the system healthy.

Any thoughts would be appreciated.

Hello,

That approach would work fine. If you wanted to try and remove all and fill with fresh you can disconnect the heater hoses at the engine and blow out the system with very low air psi (about as hard as you can blow). I think about 8-10psi. Then there might be a drain at the bottom forward part of the engine with a small drain valve, D4's have this. That would drain coolant from the block and opening the heater valves would drain the coolant tank. However changing as much as you can in a shorter interval might work better. Hope this helps!!

Thanks,

 

[dclagett]

Thanks for your replies.