This is a great tool but I recommend you have the engine up to operating temperature so the thermostat is open and coolant is circulating. If it is not, you may not be removing the water in the block and freeze damage may occur. I used this system on a customer's Mercruiser 357 Magnum. When I removed the blue plastic petcocks on both sides of the lower block, only water came out. I'm glad I checked. Double check your work to be sure.

Makes winterizing easy. Found that I was better off removing thermostat. Water temperature did not go above 140 degrees and it didn't open.

This system contains the tank, hoses and shut off valve necessary to flush antifreeze into an engine, head, or raw water system, minimizing spillage and waste.

I too could not recommend this kit as is, and if following the suggested instructions. The misnomer is seeing antifreeze exit the exhaust, and the assumption is made that an un-diluted amount of antifreeze actually made it's way into the engine block/heads. See my write-ups in the BOC Tech Section. Rick aka 2850Bounty or RicardoMarine

Be sure to use Non-toxic biodegradable Ban Frost 2000, or similiar RV non-toxic antifreeze. What goes through the engine ends up on the ground.

I have been using this product for nearly 10 years and have never had a problem. I live in northern Utah and store my boat outside and I have never had any freezing problems with my outdrive or my Engine. I use this product on my 24' Sea Ray Sorento with a Alpha One Outdrive.

I would not recommend this for a raw water cooled sterndrive (I/O) because of the fact that if the thermostat does not open all the way, the engine block/heads will still have raw water or mostly water and not that much antifreeze and you would risk freeze damage because all the raw water did not exit the block/heads. The other issue is it can cause wear to the impeller esp on engines with the impeller mounted on the engine (Volvos, Bravos) because of the distance the AF has to be sucked up to the engine. This can work on outboard and on engines with closed cooling but it is too risky for raw water cooled inboards or IOs. Do yourself a favor and do not take short cuts, drain everything manually as noted in the engine manual, if you want to use AF you can back fill the engine and manifolds through the hoses. Make sure to probe the drain holes because rust flakes can prevent draining. I tried one of these years ago, then checked the block drains, what came out, was not strong enough to not freeze if the temps went down to zero...

i used on a 5.7 mercruiser and put the whole 5 gallons the unit held in and just wasnt positive it was pure antifreeze coming out of the exhaust. so i cut the top out of the jug while it was in the using position and i poured a total of 7 gallons through my motor. i just kept adding the antifreeze as it was running out, worked great and gave me piece of mind. if the unit would hold 6 or 7 gallons it would be much better design, and you wouldnt have to worry about it running out before all the water was out of engine.

Concept is great. I have found it frustrating when I use and may change out low quality components. Should work perfectly without user upgrades. Valves are junk. Threads are weak.

This is the best way to ensure that all internal parts of the Engine and and Stern Drive are protected against freeze damage .