Does the antifreeze you use really matter?

[Scott06]

Fair enough, okay then I will probably consider doing it that way, with the plugs out. If i do do it that way Im assuming any antifreeze would work since Im still going to drain it out of the engine?

If Im not wrong I only have 2 drain plugs(87 4 cylinder merc 120 inboard).

You are not wrong there are only 2 drain plugs on the 4 cylinder. IF you have power steering you may need to pop a hose off the PS cooler if it traps water.

I'm not far south of you in upstate NY and do as mentioned - drain fully, I use about a gallon to splash back into the hoses to chase any residual and chase through the PS cooler and out the drive leaving it empty with drain plugs out.

Some guys prefer to add PG in to cut down on corrosion - but this becomes a matter of choice and is like which oil is better... if it is drained as you can see the engine will last a long time...

 

[Lou C]

Here’s what I would say to people trying to decide; if you remove the stat housing & drain the block down you can see how much corrosion is actually forming in the engine since both the intake & block/heads are the same cast iron. Mine still looks pretty good despite the salt water use..I do check it because if the intake rots out there, it will put water right in the cam valley and into the motor oil…