Winterize PCM 5.7L 343

[blinddog]

Just winterized my 2012 Centurion Carbon Pro with 5.7L PCM 343. Question is how do I know if the antifreeze reached the heater core? I'm always concerned because the last boat I had, Malibu Response LXi with Indmar engine, 2 out of 7 years the heater core froze and busted even after putting pink antifreeze through the system the same way. Is there another way to make sure there's no water left that will freeze?

[h2onhk]

I always took a small shop vac and reversed the vac hose so it would push instead of vacuum, then stick the vaccum hose on the end of the "to heater" hose and blow low pressure high volume air until i saw all the water come out of the "from heater" hose. Once all the water was out I would dump antifreeze in the "to heater" hose and use the shop vac again to blow the antifreeze through the heater core until I saw the antifreeze come out of the "from heater" hose. This worked on a couple different model boats. Temps were I'm at would get close to or below zero each winter.

 

also make sure the antifreeze you are using is rated for the exposure temps.

[oldjeep]

Depends, how did you introduce the antifreeze? If you ran the engine, sucked coolant in and hoped that it displaced all the water then that was a crapshoot. If you drained all the water out of the engine, removed the 2 heater hoses from the engine and blew the water out first then you are good.

 

I drain everything then stick a funnel in the upper heater hose and pour antifreeze until it comes out the lower hose, then fill the block via the large hose on the t stat housing that goes to the circulation pump.

[JAG]

I concur with oldjeep. Same process for my MB Sports with the PCM 5.7L HO. Remove both heater core hoses, blow through until clear and you're good. I've never worried about antifreeze getting to the core. No issues in 15 years.

 

[RAWSki]

I had actually installed an 'idle pump' on my last boat that would boost water flow thru the heater core and provide much warmer air when you were not at speed (below 1500 rpm). This worked great by the way.

Made it super easy to winterize just remove the hose between the engine and pump, insert hose into a gallon of RV Antifreeze and turn on the pump until it starts flowing back out the open engine drains. Don't know why you couldn't do the same thing with a simple eco-flow hand drill pump.

[MISkier]

@RAWSki, do you have a link to that idle pump?

[RAWSki]

@MISkier -- HeaterCraft used to offer one but I don't see it on their website any longer, their installation manual still mentions the pump may be needed. I believe I bought one like this at West Marine for my installation.

 

[oldjeep]

heater-craft-circulation-pump-retrofit-kit

[MISkier]

@RAWSki, how does that mount into the flow loop?

 

By the way, I currently have my heater connected to a Y-pipe that joins/flows into the raw water intake hose before the raw water pump. Supposedly, this configuration allows the heater to continue to draw hot water from the engine at idle. Maybe the Y-pipe is the replacement for the pump. But, I like the idea of the pump for winterizing.

[blinddog]

I ran the engine for 10 minutes with water, then drained the block and manifolds (but not the heater hoses), then restarted the engine and sucked four gallons of coolant in then shut it down. Sounds like I just need to blow those hoses/heater core out with an air compressor and be done with it.

[MISkier]

@blinddog, be careful with using a compressor. I believe you only want to use 8-10 psi. I recall the dealer telling me that is what they use to protect the core, etc.

[h2onhk]

@blinddog, low pressure high volume air is the key to remove the water without damaging the core

[thager]

Just blow into one heater hose until water stops running out of the other. Put a funnel in the hose end then pour in anti-freeze until it starts to run out the other one. Reconnect hoses then drain and fill engine with anti-freeze. I have shutoff valves on my heater so I close those off before I service the engine.