View Full Version : How Much Anti-Freeze...?

11-09-2007, 03:18 PM
Started my winterization last weekend. I ran fresh water through the engine to warm it up and open the thermostat. I then drained the residual water out by disconnecting the outlet hose on the pump housing and unscrewing the garden hose-style hoses in the back. I then hooked it all back up and sucked 1 gallon of RV antifreeze into the engine. However, before running the antifreeze, I FORGOT to pull the block water plug(s) so I don't know how much water was actually left in there!

How much liquid does the block hold and did running the 1 gallon of antifreeze chase all of the water out? It was dark when I did this, so I was not able to observe if the anti-freeze started coming out the exhaust pipes (I assumed a gallon would do it).

If I have to go back and re-do it to be sure that 100% of the water is out, I will, but if you guys say that 1 gallon of coolant is sufficient to have filled the block and run the left over water out, then I'm more than happy not to do the extra work.



11-09-2007, 05:37 PM
I've got a 350 direct drive and I poured three gallons of RV AF in which seemed to just about fill it.

james yarosz
11-09-2007, 06:04 PM
JMO,but I'd bet most of the antifreeze went right out the exhaust,and very little went in the engine block.The block has to be empty for the antifreeze to go in.

11-09-2007, 06:11 PM
Probably true. My block was empty and the antifreeze filled it up. The only place it came out was the shower when I turned on the pump.

james yarosz
11-09-2007, 09:45 PM
I believe if Tim pulls the block drains he will get clear water draining out without almost no antifreeze.BTW, did you use the "pink" antifreeze or full strength green antifreeze?If you take a gallon of the pink antifreeze and put it in your freezer,guess what?,it will freeze.I replaced two freeze plugs in a friends boat last year,He used the pink antifreeze! He's lucky it only pushed out the freeze plugs and did not crack the block.

11-10-2007, 07:24 AM
Thanks for the input. I'll pull the block drains tomorrow and make sure to get everything out. Most likely I'll just leave it empty and not fill it back up with anti-freeze.

I did use the pink RV/Marine anti-freeze. If it is a known fact that the stuff still freezes, how is it even sold and promoted as an anti-freeze? -- I guess anything that has a freeze point even a couple degree lower than water qualifies, eh?

Drain cooling system
Fog engine
Pull battery
Pull impeller, coat with petrolium jelly, place in sealed bag
Pull hull drain plug to vent
Treat fuel system & fill tank
(not in that order)

Have I left anything out?

Have a great off-season!

james yarosz
11-10-2007, 01:21 PM
I like to change the oil and filter too.

11-10-2007, 04:20 PM
Way too complicated. Ten years ago nobody pumped antifreeze into their engines instead they just drained them knowing that only 10% void space is needed to keep from causing damage. It really isn't rocket science until you take away the void space and then you should analyse the liquid to see what the freeze level is much like a car except you should analyse in many points on the engine because the antifreeze/water mixture may not be equally mixed. It does have one advantage and that is reducing the corrosion inside the engine. Boat mechanics like it also because they can tell when someone has used their boat after winterizing and failed to re-winterize correctly and coming back in the spring and asking for a new engine. The mechanics have the data on the concentration to say it is impossible to freeze the engine.

11-12-2007, 10:20 AM
James was right on -- when I redrained the system, I got about 3 gallons total out and what came out of the block drains was pure water. I don't think I'll be doing the anti-freeze method again; just drain the system and let it be.

Thanks for everyone's help

james yarosz
11-12-2007, 12:04 PM
Tim,glad to hear you drained the block.I believe you will be MUCH happier with the results.