If I suck antifreeze into the fresh water system, can I skip draining the water out?

[Epic]

If I suck antifreeze into the fresh water system, can I skip draining the water out first?

2015 Tige Z3 with 6.2L Indmar base engine

Thanks, for any replies!

[UNSTUCK]

Your T-stat needs to be open to allow the coolant to get everywhere. Seems like more work than just draining the water out.

[chpthril]

I would not skip. Most the A/F will go right out the exhaust. Marine RV A/F is meant to work at 100% ratio, not mixed. next question, is your 6.2 Indmar and raptor or GM based

[freeheel4life]

15 should be a Raptor, so closed cooled(you too Josh). To drain those years there should be a plug on both exhaust manifolds. Vdrive anode. Heat exchager drain plug. 1 plug on the tube leading to the raw water pump. Once those are drained then run on antifreeze. Since you dont have to wait for Tstat to open you dont have to run that long to get antifreeze all the way thru vdrive, heat exchanger, trans and oil coolers, then manifolds. Thats how we do it. I use a refractometer to verify burst point isnt too low from any water dilution.

[chpthril]

15 should be a Raptor, so closed cooled

Thats what I was wondering, just couldnt remember when they went blue-oval.

[freeheel4life]

I admittedly have run Raptors without pre draining and just continually dip my refractometer into the exhaust until it -50 burst, but you have to run a lot longer to get there.

[chpthril]

With a raw water heat exchanger and manifold, I can see it taking far less A/F to push the water out. Sounds sound to me. But with a full raw water engine, like the previous PCM GM, very little water in the block will be displaced by the A/F.

[freeheel4life]

Yessir. Always pull knock sensor/plugs on them 343s and both the Indmars that come after. The 409s are CC. The 409 raw water flow is so ridiculous. Trying to get all my 409 customers to spring for the Indmar flush kit this year.

[Epic]

Thanks for the reply. It is the Raptor.

[Epic]

Thanks for he replies here, everyone. I will drain first, like last year. In case it helps some one, here are some notes I made last year.

09C28498-CAAD-4ADE-A2BE-8EE30FA21881.jpg

[UNSTUCK]

So if one was to drain the system first and then pump in antifreeze via a plunger, how many gallons of rv coolant is needed? What do you do with the ballast system?

[Ochrod]

I think on my 2011 343 I pushed through about 6-8 gallons after draining all water. But does a person need to run anti-freeze through it after draining? Kind of wondering as I may store on a lift next year.

[chpthril]

But does a person need to run anti-freeze through it after draining?

Nope? Air wont freeze and expand. So if you get a thorough drain the first go-round, antifreeze is not needed for freeze protection.

[crabo227]

Draining and then antifreeze may be overkill, but peace of mind is worth a lot.

[bsreid]

This was the first year I used antifreeze mainly because of rust prevention in the pnw, along with added protection.