Winterization /coolant change 2008 zr6 390 super air 220

[ckevans98]

I am requesting confirmation on the Winterization process for my engine.
There is 2 cooling systems if I am correct. Raw water from the lake and fresh water cooling system with ethylene glycol coolant. The mechanic removed the intake hose and sucked up 5 gallons of antifreeze until it was coming out of the back red. He said it did not need to get to temp to open the thermostat to reach the block because the glycol system incorporates the block. Also the heater in the boat is on the glycol system and does not need antifreeze run thru it. Is this correct? Does the glycol system need an antifreeze solution? Does this glycol need changed frequently? is changing the glycol something that needs a auth mechanic? do you test the glycol system for Alkalinity?
Thanks in advance.

[Infinity]

I am making some assumptions below that your ZR6 and my ZR409 have similar set up but I am honestly not familiar with your engine since I have not owned one.

Yes, if you have a partial closed cooled engine on your ZR6, then the Glycol AF incorporates the block and the heater (this is how my ZR409 is set up)....and you do not add any other AF to that since its already anti-freeze, just a different kind...much different than the AF you suck into the water cooled portions of engine after draining the lake water. Glycol Eth is toxic and not something you want dumping out of the exhaust system onto the ground.....the RV anti-freeze is non-toxic.

Yes, PCM recomends that you test the glycol system for alkalinity each year and if it continues to test well....then replace it every 5yrs. Whether a mechanic is required for this depends on you. Really its just a matter of draining the old anti-freeze and then filling the proper amount with the correct new antifreeze (my ZR409 calls for DEX-COOL in the partial closed cooled system). Actually since my boat is a 2014 bought new in 2015, I am going to change my DEX-COOL this winter. Honestly I have not tested the alkalinity, its not a tool I have bought yet and I do all my own work and do not take it to dealer/mechanic. I need to get one for future testing since I believe once it loses its akalinity, it can have corrosive qualities that are not good for the engine.

To winterize engine, the lake water is drained by pulling the drain plugs (mine has 4 on the exhaust risers, 1 on the heat exchanger and 1 under the v-drive), as well as disconnect the hose to the impeller housing to get water out of that hose loop. After doing that you re-install the drain plugs and then fill with the RV anti-freeze (non-toxic type). Many do not fill the system with the RV AF, they just drain everything.....many (including me), fill with the AF since it has some properties that help prevent corrosion, but that also depends on the climate where you live.

From your post....could not tell if your mechanic first drained the lake water before sucking up the 5gal of anti-freeze? Assume he used the non-toxic kind that is pink in color and not normal AF. In the South, there are some dealers who do not drain the water first because it does not get that cold. I personally would not take that risk even tho where I live does not get super cold since there is no way that just sucking up the AF replaces all the lake water in the cooling system and you end up with diluted AF. For me, likely never an issue but I am too OCD. However in areas that see cold temps for long periods, no way I would sleep well at night and I would think living in PA would put you in that category where you would want to be sure to drain all water BEFORE sucking up the AF.

Also smart to put some of the AF into your ballast lines (couple quarts) and then run ballast pumps in reverse to get any residual water out of the pumps/lines and make sure that does not freeze up. You can use funnel to pour some into the line (I remove all my PnP bags for layup and take them out of the boat).
Its also recommended to change your engine oil before winterizing so you have fresh oil in the engine, personally I also change my DEXIII transmission fluid as well.

If you do not have your owners manual....you can find a copy of it on this site by clicking on the tab above that says "manuals/brochures".