R31 320HP D4 coolant change

[zekeandboone]

2021 R31 320hp.... Anybody done a coolant change?

 

[American Flyer]

2021 R31 320hp.... Anybody done a coolant change?

Hi Steve,
We had it changed during our annual service last year. The complete system was drained, including the water heater loop. Is yours needed already? I guess it is near the 4 year mark isn’t it. Time flies!

 

[S. Todd]

I change ours every year with the amount that will drain from the block, about 12 quarts. That way, I suspect the amount remaining in the cabin heater and water heater core get sufficiently diluted with new coolant and there is reasonably fresh coolant throughout the system. Otherwise, I am not sure how you would remove all the coolant from the system unless you disconnected numerous hoses and used a vacuum to attempt to remove all the old fluid.

 

[American Flyer]

Hi Stewart,

Wow! Unless you are putting 2000 hours on your engine every year, changing the coolant that often seems wasteful and environmentally unfriendly; those chemicals are “hazardous and harmful to the environment”. I hope you are disposing of it properly. Unless your manual differs from mine the recommended interval is every 4 years or 2000 hours.

I do not profess to be an expert on the system but it appears to me the majority of my hot water system is above the level of the lower drain cock on the engine block and the plumbing is more or less horizontal with the exception of the hoses where they enter the engine compartment. If a siphon is started I would suspect that draining the block will drain the majority of the hot water system.

I could be wrong, but I do not think my Volvo Penta certified mechanic is. He assured me that he replaced the coolant in the entire system, including the vessel hot water portion. I don’t believe he used a vacuum pump or disconnected any unusual amount of hoses during the job. Again, I could be wrong, I was not present during the entire time he was servicing the boat. I guess he could have lied and just charged me for extra coolant, but I do not think so. I think he removed all the coolant from the system. If you would like to know how he accomplished this I can forward his number.

 

[S. Todd]

D-4 coolant capacity in our 2021 model is 13 liters. I get less than that (only about 11 liters) from the drain on the block so I am fairly certain nothing comes from the hot water system or the cabin heater. It may cost me a little bit more than doing it less often, but in the scheme of things it is a minor maintenance cost. It gets properly turned in for disposal by me, and I presume those that are responsible for doing so do not damage the environment with it.