mercruiser 3.0 freeze plug blew out

[cdoo1972]

Re: mercruiser 3.0 freeze plug blew out

Since you mentioned that about acetone and seals I took the manifold apart and cleaned it and will replace those gaskets too. While blowing it out I found a spring. I also pulled off the thermostat housing and found where the spring came from. By the looks of the thermostat its been broken for a long time. Maybe I got a little coolant in the block. Wishful thinking I know..

 

[JimS123]

Re: mercruiser 3.0 freeze plug blew out

Once the block fills with water, it just circulates between the block and the water pump until the thermostat opens. The thermostat dumps some of the block water out the exhaust and the same amount of of cold water mixes with the hot water in the block to hold the temperature at the thermostats opening temperature.

One you drain the block and refill it with antifreeze that is well below 100F, the T-Stat closes again until the block heats up.
So pre heating the block is really an exercise in futility.

But, that's not the procedure. The engine is running for 15 minutes on cold tap water from the hose. The Tstat is open and circulating. That can be checked. Now, the engine is shut off and within 30 seconds the muffs are switched from cold tap water to hot antifrz in a jug. Within seconds the motor is running again and now the antifrz is circulating. There is no thermal shock.

I admit when I started this maybe 15 years ago I did it because of the advertising hype in a catalog, so I bought the "kit". Also, I saw the local marina doing it this way for customer's boats, so I didn't give it a second thought. My Mercruiser is an old model with brass plugs and only 1 stopcock. It was always a pita to winterize, after pulling the plugs and draining, further needing to pull the hoses and backfill everything with anti-freeze. Before anybody recites the tired phrase "air don't freeze", it was the Merc manual that I was following.....they recommended antifrz after draining.

Anywhoot, being anal about being sure, after I finish the antifrz muff flush I always drain a pint or so from the single block drain and check the SpG. It's almost straight antifreeze! Haven't froze one yet. Maybe a little common sense following the directions is all that's needed.

 

[Bullrider]

Re: mercruiser 3.0 freeze plug blew out

But, that's not the procedure. The engine is running for 15 minutes on cold tap water from the hose. The Tstat is open and circulating. That can be checked. Now, the engine is shut off and within 30 seconds the muffs are switched from cold tap water to hot antifrz in a jug. Within seconds the motor is running again and now the antifrz is circulating. There is no thermal shock.

I admit when I started this maybe 15 years ago I did it because of the advertising hype in a catalog, so I bought the "kit". Also, I saw the local marina doing it this way for customer's boats, so I didn't give it a second thought. My Mercruiser is an old model with brass plugs and only 1 stopcock. It was always a pita to winterize, after pulling the plugs and draining, further needing to pull the hoses and backfill everything with anti-freeze. Before anybody recites the tired phrase "air don't freeze", it was the Merc manual that I was following.....they recommended antifrz after draining.

Anywhoot, being anal about being sure, after I finish the antifrz muff flush I always drain a pint or so from the single block drain and check the SpG. It's almost straight antifreeze! Haven't froze one yet. Maybe a little common sense following the directions is all that's needed.

So do you think this will work?
I have a 5 gallon bucket that hooks to a ladder higher than the stern. It has a hose through the bottom that runs water down to the muffs. I am running clean water into the bucket down through the system as the engine warms up. Once warm I disconnect the fresh water supply and watch the water line go down to the boottom of the bucket, then I start to pour antifreeze in the bucket till I see a pretty color coming out the vented places .
engine off , go have beer
Any thoughts on this?

 

[Bullrider]

Re: mercruiser 3.0 freeze plug blew out

Ayuh,.... 1 of my Mentors, God Bless 'im, always said 6 hours at 26? is a Cracked block,....

But,.... I've never tested his theory,....

Thank YOU!!!!

 

[thumpar]

Re: mercruiser 3.0 freeze plug blew out

So do you think this will work?
I have a 5 gallon bucket that hooks to a ladder higher than the stern. It has a hose through the bottom that runs water down to the muffs. I am running clean water into the bucket down through the system as the engine warms up. Once warm I disconnect the fresh water supply and watch the water line go down to the boottom of the bucket, then I start to pour antifreeze in the bucket till I see a pretty color coming out the vented places .
engine off , go have beer
Any thoughts on this?

Or just drain it. Just because it is coming out the transom or prop doesn't mean it is going in the engine. Look at the cooling diagram more.

 

[Bullrider]

Re: mercruiser 3.0 freeze plug blew out

Or just drain it. Just because it is coming out the transom or prop doesn't mean it is going in the engine. Look at the cooling diagram more.

I think that sounds safest. I just didnt know if there are pockets that will never drain, but what Im reading here I like draining instead of a Frankenstien settup pouring antifreeze down to the rivers and wells.

 

[Scott Danforth]

Re: mercruiser 3.0 freeze plug blew out

folks, there are no short cuts in winterizing. you have to drain it, or you gamble your block trying to suck antifreeze thru muffs. Period.

why take a gamble on the $.020 worth of wax in the $3 thermostat that may or may not stay open.

Air doesnt freeze. it the antifreeze "trick" worked, there would not be these threads. the fact that there were about 80 of these threads last years is enough of an indication that it does not work. my guess there will be about twice as many this year.

 

[wrench 3]

Re: mercruiser 3.0 freeze plug blew out

But, that's not the procedure. The engine is running for 15 minutes on cold tap water from the hose. The Tstat is open and circulating. That can be checked. Now, the engine is shut off and within 30 seconds the muffs are switched from cold tap water to hot antifrz in a jug. Within seconds the motor is running again and now the antifrz is circulating. There is no thermal shock.

I admit when I started this maybe 15 years ago I did it because of the advertising hype in a catalog, so I bought the "kit". Also, I saw the local marina doing it this way for customer's boats, so I didn't give it a second thought. My Mercruiser is an old model with brass plugs and only 1 stopcock. It was always a pita to winterize, after pulling the plugs and draining, further needing to pull the hoses and backfill everything with anti-freeze. Before anybody recites the tired phrase "air don't freeze", it was the Merc manual that I was following.....they recommended antifrz after draining.

Anywhoot, being anal about being sure, after I finish the antifrz muff flush I always drain a pint or so from the single block drain and check the SpG. It's almost straight antifreeze! Haven't froze one yet. Maybe a little common sense following the directions is all that's needed.

I think the key phrase here is "...they recommend antifreeze AFTER DRAINING".

 

[JimS123]

Re: mercruiser 3.0 freeze plug blew out

Air doesnt freeze. it the antifreeze "trick" worked, there would not be these threads. the fact that there were about 80 of these threads last years is enough of an indication that it does not work. my guess there will be about twice as many this year.

The threads are usually asking about the procedure, not complaining later. All the marine catalogs sell the "kit", so that's why the questions arise.

Be that as it may, the SpG of the contents of the block tells the whole story. If there's water in there the simple test will identify it.

 

[garbageguy]

Re: mercruiser 3.0 freeze plug blew out

I don't know why people think they know more than engineers.

I'm definitely gonna use that one

 

[Starcraft5834]

Re: mercruiser 3.0 freeze plug blew out

Because air doesn't freeze until around -350F and it is free.

little more need be said........

 

[UncleWillie]

Re: mercruiser 3.0 freeze plug blew out

... I don't know why people think they know more than engineers.

I don't know why the engineers think they know more than the thousand of end users who know the procedure in the manual doesn't work!

Question Everything!

 

[alldodge]

Re: mercruiser 3.0 freeze plug blew out

I don't know why the engineers think they know more than the thousand of end users who know the procedure in the manual doesn't work!

Question Everything!

+1, just cause the person has the degree doesn't mean they know what there doing (Top or bottom of the class still gets a diploma). A good engineer uses input from users to change things that work

 

[Scott Danforth]

Re: mercruiser 3.0 freeze plug blew out

I don't know why the engineers think they know more than the thousand of end users who know the procedure in the manual doesn't work!

Question Everything!

the manuals are written by technical publication writers. not nescessarily engineers. However I do take offense to the statement. Walk a mile in someones shoes before you comment.

 

[Lou C]

Re: mercruiser 3.0 freeze plug blew out

The engineers who wrote the manual never told the end user to use the suck the AF up the drive method. THAT is the method that about half the time does not work and results in a cracked block. That, you got from un-informed hatchet mechanics on the 'net. They (Merc & OMC) told you to drain everything and back fill the engine and manifolds with AF. I've done that for 10 seasons and it works just fine.

 

[garbageguy]

Re: mercruiser 3.0 freeze plug blew out

A good engineer uses input from users to change things that work

Not to hijack, but Dodge makes a good point. Engineering is the practical application of technology.

 

[JimS123]

Re: mercruiser 3.0 freeze plug blew out

Engineers are always the root of the problem. They can be smart as a whip, take efforts to marry theory to practical application, and then spend eons testing in the field with customers, and then along comes some shade tree mechanic who lazily eliminates that one seemingly unimportant step. End result is disaster and its the Engineer's fault.

Test 1 - water in the block 1.00 = 32 F freeze temp. Test 2 - pink stuff in the gallon 1.045 = -55 F freeze temp. (confirms the label). Test 3 - water in the block after the "faulty" procedure 1.039 = -35 F freeze temp. Test 4 - repeat if you screwed something up and test 3 gave an answer you didn't like. Good to go! What's so hard about that?

IBoats actually sells the faulty equipment winterizing flush kit that is being criticized here. Maybe we shouldn't bite the hand that feeds us....just sayin.

 

[Lou C]

Re: mercruiser 3.0 freeze plug blew out

I got into a discussion with some of the rocket scientists at West Marine about why their winterizing kits should not be used on a raw water cooled engine and they don't get it. I am amazed (but I should not be) at the lack of mechanical common sense present in most people that work in service industries today.
When I became a driveway mechanic, I learned most from reading shop manuals. There was no internet, and there was less bad advice being spread around. Now no one reads those manuals except some of us and real mechanics. So to all you beginners, you have heard the right way to learn, its up to you to learn that way. The universe is not explained on You Tube LOL....

 

[tpenfield]

Re: mercruiser 3.0 freeze plug blew out

Since I am an engineer ( but now work in I. T. ), I could probably set up an experiment to demonstrate why the AF (only) method of winterizing is not all that effective and results in freeze damage at lower temperatures.

Keeping with the times, I could probably post it on YouTube or Facebook since reading hard-copy has become passe.

FWIW - I used to use the AF only method until 1 year, I was working on my raw water cooled boat engine (in my F-242) after a cold snap (-10 F ish) and happened to take the exhaust elbow & manifold apart. The liquid inside the exhaust manifold chambers was quite slushy and nearly frozen solid. . . even though I had used 7 gallons of AF to winterize it. Fortunately it did not hard freeze, as it would have busted something. Since then, I have drained things down after running the AF.

I do like the fact of running AF in through the cooling system as that effectively treats the water intake lines, sea water pumps, oil coolers, etc. that leads up to the engine. However, I still drain the engine and manifolds.

 

[UncleWillie]

Re: mercruiser 3.0 freeze plug blew out

...FWIW - I used to use the AF only method until 1 year, I was working on my raw water cooled boat engine (in my F-242) after a cold snap (-10 F ish) and happened to take the exhaust elbow & manifold apart. The liquid inside the exhaust manifold chambers was quite slushy and nearly frozen solid. . . even though I had used 7 gallons of AF to winterize it. Fortunately it did not hard freeze, as it would have busted something. Since then, I have drained things down after running the AF.

I do like the fact of running AF in through the cooling system as that effectively treats the water intake lines, sea water pumps, oil coolers, etc. that leads up to the engine. However, I still drain the engine and manifolds.

-50F antifreeze begins to form slush at +15F. -50F is where it freezes solid not where it starts to solidify.
By -10F you should expect to find the antifreeze in a completely non-liquid state.
It will look solid and dry but poking it will demonstrate that it has very little strength.
Of course all this assumes that you have not diluted it in the winter flushing process. This is the key!

Place some brand new antifreeze in a glass and place it in your kitchen freezer (~-5F) and it will become firm enough that turning the glass upside down will not spill a drop. Poke a finger into it and you will find that it is really just a weak slush.

All that said. Drain, AF Flush, and Drain again covers all bases!