4.3L Method of Winterizinig Block

tahoejag

Petty Officer 1st Class
Joined
Jul 4, 2009
Messages
229
First off...let me start by saying this is my method and have found it VERY effective. I live in the very northern region of the U.S. and it gets COLD! I have not had any problems of a freezing block year after year. I would put boat for boat by using this method for anyone who disagrees. I do respect all for their own way of winterizing; however this works for me. Provided is a link for the diagram of water flow, t-stat testing, and vent/drain holes for drive unit.

http://www.boatfix.com/merc/Techbk/94/94hg6a.pdf

First thing I do is make sure all vent/drain holes in drive unit are clear with a piece of wire. I then hook muffs up and run to temp then FOG engine at this time. Engine now off and fogged, I can now service gear lube and change the oil. Once done... I trim the drive all the way in. Remove muffs - I NO LONGER need them. Remove all 5 blue drain plugs and purge with wire while draining. Raise and lower boat with trailer jack to each limit to drain any excess water from engine then return boat/engine to a level positiion. Next, remove all six water hoses that are attached to t-stat housing and remove housing for t-stat service and testing (see link). I leave the t-stat housing removed. I then use compressed air to blow out all six hoses that I just disconnected fm t-stat housing (same method for sprinkler systems). I re-install the 5 blue drain plugs back in, (yes I do put plugs back in) b/c I just got done draining and clearing all the water out and thats why I don't use the muffs any longer, because I DO NOT want to add any more water. Using 3 gallons, yes only 3, with some left over (and not 5 gallons probably b/c of what leaked out of the muffs by using the additional 2 gallons) of -100f marine grade AF. I start filling up each of the riser and exhaust hoses until AF comes out of the back/bottom of the transom. Then I fill the water intake hose which will discharge AF out the lower drive unit. At this time I check the concentration of AF from the back of the transom for the freeze point. I then fill up the circulating pump hose until AF comes out of the t-stat outlet on the top of the intake manifold. I then re-install t-stat, housing and hoses. I AM NOW DONE!

With this method I serviced oil, gear lube, t-stat and fogged engine and have a sample of AF concentration to test to have peace of mind. #note# I didn't use the muffs or a winterizing kit, used only 3 gallons of AF and I did put drain plugs back in.

Again, just my method that is effective and wanted to share. :)
 
Top