freeze question

[mattttt25]

trying to help a few friends out. both bought brand new boats with merc i/o's (135hp, 260hp). both are trying to get as much boating in before the winter. they are convinced that as long as they turn a little knob on the top of their engine that allows cooling water to drain from the block, that they will be fine if a freeze occurs. is this true? is a drained engine safe from freeze, or do they need the green stuff inside to be certain? thanks-

 

[Capt Ken]

Re: freeze question

Not heard of a little knob that would drain the engine unless its one of those new fangled air powered drains. If the engine is drained of all water, it will not freeze and doesn't have to have anti-freeze added. Anti-freeze only prevents corrosion from building up in the water passages when air is introduced into the system and is an added protection in case all the water didn't exit the block.

 

[mattttt25]

Re: freeze question

as new 2002 engines, they both have a knob on top that actuates a valve at the bottom of the engine. when turned, water pours out of the engine and into the bilge. do you think this suffices to protect against those late night freezes?

 

[Capt Ken]

Re: freeze question

Does this knob also drain the manifolds and the power steering cooler on the V8? I know Mercruiser has a air drain system that you open a valve and apply air and it drains all water but haven't seen one or used one. Somebody help me here. Us Florida boys don't see much freeze problems.

 

[mattttt25]

Re: freeze question

yeah, don't know... they assume the engine is fully drained and safe by just turning this knob to open one valve. hope they're right...

 

[kdmiller8251]

Re: freeze question

For what its worth, I am not an expert but I would be wary of just turning one thing and all water draining out. Does this open a drain down low on the block? I cant really see one valve opening a drain on the block and the manifolds..If you were using air to flush the system out I could believe that but not the other way. I would throw some antifreeze thru the system just to be safe. Would hate to crack a brand new block...

 

[AdmiralQ]

Re: freeze question

I am far from an expert, but I don't think one drain could empty the entire cooling system, especially the water pump and thermostat housing, without the system being pressurized, i.e. compressed air. Also, what about the water lines coming from the sterndrive unit? Although the block might be drained, wouldn't water still be sitting in the lower unit? That's a lot of $$$ to repair/replace a lower unit.

 

[geriksen]

Re: freeze question

Yes, there is such a thing. Some of the new Mercruiser engines have a single point drain system that is supposed to drain everything. there is a matrix of hoses and valves that make this all happen. It is a great idea for the consumer but I personally have my doubts about how well it will work. When we drain engines at our shop, we almost always have to clean out the drain holes with a pick or small screwdriver. The hoses on this system are tiny. Here is a paragraph from Merc's website about which engines have it.<br />Water Drain System: Alpha: Manual single-point drain w/rotary valve control located on front; Alpha/Bravo Opt.: Hand-removable plugs on port, starboard and front; Bravo: 3-point manual system with drain plugs; Bravo Opt.: Air-actuated, single-point system, pump included

 

[mattttt25]

Re: freeze question

thanks fellas. sounds like they should be safe, but should still use antifreeze if engine will be layed up for an extended period.

 

[RKing3]

Re: freeze question

Speaking of Mercruiser Alpha Ones, I've just inherited a 1989 5.7 liter with fresh-water cooling and no books. I tried to use my Mercruiser 120 experience but the fresh-water system has me stumped. Every draincock produces green (anti-freeze) water. I can't find any sea-water drains. I'm going to work on getting a book, but it's cold tonight and the book won't get here in time. I'm using a small heater in the engine compartment. HELP!

 

[MrBill]

Re: freeze question

Matttt.....I can certainly appreciate "extending" the season, and your friends should use reasonable judgement with the new system. Obviously, proper winterization goes beyond the simple draining.<br /><br />Crown3....there are several items that must be located and drained. 1 - Exhaust manifold drain plug, 2 - Exhaust elbow drain, if applicable to your engine, 3 - power steering cooling drain, if applicable, 4 - the heat exchanger drain, it is the underside, rear most plug. You can easily miss it and think you tried all the drains, but it is definitely there. Good luck, hope the manual comes soon.

 

[RKing3]

Re: freeze question

Thanks, MrBill. I'll start looking for those plugs at first light. Then maybe I can get my heater back.

 

[Trent]

Re: freeze question

Time for a change in Mercrusier!<br /><br />Better get used to the new "Easy Water Drain" "Smartcraft Gages" and "555 Control Modules"<br /><br />Hope they work?

 

[Walter]

Re: freeze question

Never mind...<br /><br />I was gonna reply to Crown's post re: antifreeze, but I misunderstood what he was saying. Pays to read bit more carefully...<br /><br />Walt