Antifreeze Type / Winterizing a GM 4.3

[dbear1959]

Just bought a boat this summer. 4.3 litre GM I/O engine. Previous owner would completely drain the engine open the drain plugs & then completely refilled the system with the pink RV type antifreeze from a gravity type 5 gallon tub through the muffs.

Question is is this suffucuent or should I use a standard Prestone / Peak type automotive antifreeze straight or 50/50 mix. Also it is a 1996 engine. would you use the old traditional green antifreeze or the newer orange Dex cool? I'm not sure if one offers a better protection/corrosion factor or if it just comes down to the price issue on the anti freeze. I live in Michigan so I want to make sure I'm using the right thing and doing it the right way. Thanks in advance.

 

[Daviet]

Re: Antifreeze Type / Winterizing a GM 4.3

I would suggest that you DO NOT use automotive type antifreeze unless you have a way to collect it in the spring. Around here it is not acceptable to contaminate the lake with antifreeze. Thats why the person you bought it from used RV antifreeze, no contamination problems. There is actually nothing wrong with just draining the cooling system. Was done for many years without problems, some of us still do it that way.

 

[Bondo]

Re: Antifreeze Type / Winterizing a GM 4.3

I live in Michigan so I want to make sure I'm using the right thing and doing it the right way.

Ayuh,... The Cheapest, Easiest, Simplest, most Envionmentily friendly way to winterize a boat is,.......

Drain it,... Drain All the water out of it,.... Air just does Not Freeze...
Even at 45? below 0,...

 

[Lodgepole]

Re: Antifreeze Type / Winterizing a GM 4.3

Yeah But, iron that is left wet and exposed to air rusts much more than iron covered with antifreeze. Draining and not filling with antifreeze will rust out your manifolds, etc. much faster.

 

[Bondo]

Re: Antifreeze Type / Winterizing a GM 4.3

Yeah But, iron that is left wet and exposed to air rusts much more than iron covered with antifreeze. Draining and not filling with antifreeze will rust out your manifolds, etc. much faster.

Bullship.... Baring Saltwater boats,...
I've got freshwater cast iron that's 40 years old,+ still in excellent condition...
The Drained motor drys out,+ corrosion never get's beyond the expected patina...

 

[boat1010]

Re: Antifreeze Type / Winterizing a GM 4.3

I have always been a firm believer that water is a pretty big corrosive agent. I use automotive antifreeze on mine. I put muffs on it in my driveway to get it out before I go to the lake. Some people drain it out and save it but I don't. I have a drill pump, I mix the antifreeze in a bucket about 50/50 and run the boat till it warms up with muffs so the thermostat opens. Then hook up the muffs and the drill and restart the boat and run it while sucking the antifreeze out of the bucket till the water coming out of the exhaust is green. Has worked for years.

 

[Chris1956]

Re: Antifreeze Type / Winterizing a GM 4.3

dbear, a 4.3L V6 motor will have drain plugs on each side of the block and at least one on each manifold. After you have changed the oil and fogged the motor, turn it off and remove the muffs. Now pull the four plugs and let it drain. Now pour full strength antifreeze into the raw water pump until it exits the outdrive water intakes. Pour AF into each manifold hose until it exits the drains. Install the drains and fill to top of manifold. AF should exit outdrive as well thru prop and perhaps idle relief holes. Repeat with block, by dumping the AF into large hose on water circulating pump.

In the spring, pull the four plugs and let the AF drainout the boat's transom drain into a pan. Save and reuse next winter. I always used the green auto stuff at full strength. if there was some residual water trapped in the block, it would dilute the full strength AF a bit, but the block was still protected. You will need about 4 1/2 gal of the AF initially, but only 1 gal next year, if you reuse it.

 

[Apollo75]

Re: Antifreeze Type / Winterizing a GM 4.3

Bullship.... Baring Saltwater boats,...
I've got freshwater cast iron that's 40 years old,+ still in excellent condition...
The Drained motor drys out,+ corrosion never get's beyond the expected patina...

Finally someone that will admit like me that heavy cast iron can last more than a few years.

I have drained mine but was thinking of using anti-freeze this year. I will stick to draining them.


OFM

 

[Alumarine]

Re: Antifreeze Type / Winterizing a GM 4.3

Finally someone that will admit like me that heavy cast iron can last more than a few years.

I have drained mine but was thinking of using anti-freeze this year. I will stick to draining them.


OFM

My manifolds are only 35 years old and still look good with only draining.

 

[Maclin]

Re: Antifreeze Type / Winterizing a GM 4.3

The cast iron internal passages will outlive the other components in the engine (unless it is has had salt/brackish water sitting in it for very long and not flushed with "city water"). Draining is the key.