Coolant Change D4 Volvo

[Jfrano]

Don’t see much written up on coolant change and I don’t think it’s covered in any of “As the Prop Turns” segments.

So from the manual looks like there are two bleeder screws on the port side. Is the process to drain the fluids from both of these drain plugs ? Will this remove all the coolant throughout the system and including the water heater? Do you then flush with fresh water through the filler cap before refilling with new Volvo 50/50 mix?

Any insights appreciated, will be doing for the first time soon.

Thanks
Joe

 

[BB marine]

Using the two drain nipples and hose drain the antifreeze until the block is completely drained. I remove the two coolant hoses from the block that go to the BUS heater and Hot water tank. Using water in a bucket ( I buy 5 gallons of distilled water for flushing this is over kill but it is a way to make sure the water used is not hard water or full of minerals) I attach one coolant hose a a drill pump and place the other hose into a container to capture the antifreeze from the hoses, bus heater and hot water tank. Trigger the drill and start pumping water through the hose until all antifreeze is removed and clear water is coming out of the hose draining into the container. I reinstall the hoses on the block, fill the engine block with the distilled water. Start the engine and put it under a load for 15 or 20 minutes to warm the engine and circulate the water though to the block and coolant system. When I do this maintenance I am usually doing more than anti-freeze replacement.When I have the engine warmed up I need it to cool down for a while so this is the perfect time to change the oil. After changing the oil and filter it is time to drain the coolant system again. This time drain the flush water. Once the block is drained I remove the coolant hoses again this time I use the drill pump to flush the water and fill the lines with antifreeze. I repeat by attaching one coolant hose to the drill pump and the other hose in a container. I pump the antifreeze into the hose until it comes out the other end removing all the water from the hoses and heaters and replacing with new antifreeze mix. I then install the hoses to the block. With the block empty this is a good time to replace the Thermostat which is located forward end of exhaust manifold. Drain nipples closed fill the block and manifold with anti freeze mix until full. Once full run engine under a load to get it up to temperature. Let 6he engine cool and check fluid level top it off and inspect hoses and thermostat housing for leaks. You should now be good for a 2 years of service or 400 hrs until the next coolant maintenance schedule.

 

[Jfrano]

So as you pump out the distilled water
With the antifreeze mix, have you
Measured any dissolution of the 50/50 ratio? To something less?


Thanks

 

[BB marine]

No you will see a noticeable difference clear water and then yellow antifreeze the dilution is not even measurable.

 

[AGLyme]

Is there a video online showing these steps ?
Thank you

 

[Cutwater28GG]

also know that there is a lot of places air can get trapped and you will likely need to check and top up levels after the change. the level sensor is also very sensitive.