PCM Closed Cooling Antifreeze Change 6Litre

[EricKelley]

I own a fantastic 2015 Ski Nautique 200 with just over 600 hours.  I have neglected to change the antifreeze on the closed cool part of the system.  The Dexcool antifreeze has a max life of 7 years so this needs to be changed.  I have had no luck reading the manual or you tube videos finding out how to bleed the system so that no air pockets form or capacity of the system.  I think to drain you remove the large hose to water pump, the knock sensors to drain the block and the plug on heat exchanger?

No process to add fluid is given.  Anyone done this?

Thanks

[BraceMaker]

I think you're in your own head on this one.  I've never had an issue with a closed loop boat and adding antifreeze.

I've had terrible times refilling some cars but that's because in modern cars the radiators aren't the high points like they used to be and even then so many cars don't have a radiator cap just an expansion tank.  That makes cars kind of tricky doing things like filling them with the heater on full bore and the front of the car jacked up in the air or parked uphill.

On the boat you should have a cap on the heat exchanger and that's probably higher than the engine is so it should fill very easily.

[Ski_Dad]

you can probably just drain a few gallons via the heat exchanger and then add a few back - that's what I'm doing to freshen it up - i don't see any reason to bleed the system.

[BraceMaker]

52 minutes ago, Ski_Dad said:

you can probably just drain a few gallons via the heat exchanger and then add a few back - that's what I'm doing to freshen it up - i don't see any reason to bleed the system.

I don't know about that coolant has a bunch of components for different purposes such has buffering against pH change and to prevent corrosion.  Dexcool was famous for a bunch of issues from plastics breaking down into it and engine failures when it came out.  So I would just go whole hog.  I'd rather change oil partially and add a filter than partially change and mix coolant but that's just me.

[RichardDoane]

it's not a big deal to drain the system and re-fill with your 50/50 dexcool mix. you can just carefully refill into the expansion tank and leave room for air to escape once you restart the engine and let it idle and slowly warm up.  pay attention to the temp gauge and as it warms up, thermostat will open, and you'll need to add coolant until the system is full.  we use a vacuum deal, but not everyone has access to that kind of shop equipment.

inexpensive kit from Amazon :https://www.amazon.com/OEMTOOLS-24444-Cooling-System-Refiller/dp/B01BW39HJS/ref=sr_1_7?keywords=coolant+vacuum+refill+kit&qid=1679374420&sr=8-7

 

[EricKelley]

Thanks for the replies.  Jody called me and echoed the above comments.  He did give me a couple helpful hints.  The Allen screws on top of the exhaust manifolds are bleed points and after he fills the system he puts some coolant in there.  He recommends checking the screen near the thermostat and inspect/replace the anode.  He says in most cases no need to open and clean passages of the heat exchanger.  He recommends good clean up to this messy job and uses shop vac to remove excess coolant.  Don’t want your boat to smell like antifreeze.

Richard that tool is fantastic.

[paul]

Did this last fall and same as you couldn’t find any write ups so posted this on planet Nautique: https://www.planetnautique.com/vb5/forum/nautique-topics/maintenance-technical-discussion/diy-articles/659022-2014-pcm-zr409-6-0l-coolant-flush-diy-notes

Edited March 21 by paul

[DW]

It is a good practice to measure what comes out and make sure the same amount goes back in, I use old milk jugs for these type of processes.  As the excellent write up indicates, the system appears to need a few burps to get all the air out.