Winterizing without removing Thermostat?

[sharboat]

I am looking for an easy way to winterize my 4.3L Mercruiser I/O without taking the time to let the motor come up
to operation temp. and wondering if thermostat is fully open so I can let winterizer fluid to flow into all motor passages.

I have on occasion removed the thermostat to make sure the fluid does it's job - but that is a bit of extra work.

Is there a way or kit on the market that can bypass the thermostat during the winterizing process and the close for
normal operation?

 

[Don S]

Re: Winterizing without removing Thermostat?

Just drain it all first, then run it with your "winterizer fluid" if you feel the need. Air don't freeze.

 

[ziggy]

Re: Winterizing without removing Thermostat?

ya don't need the t stat to be open to drain the water out of it. when all the water is out. your risk free of a cracked block or manifolds next season. trick is to be sure all the water is out of it. i used to drain all the water out then introduce pink anti freeze via the tstat too. i gave up on this because air don't freeze and i found the extra step of removing the tstat just another step to winterize that i don't think is necessary (i don't know of anyone who's block rusted thru from the inside out, not necessarily true for manifolds though, my last one rusted thru from the inside out). . so i just drain all the water out..
w/o binging the engine up to operating temp, i will be harder to drain the oil out of it to do an oil change. i use an oil extractor and if the oil isn't warm, it won't flow so i can't drain the oil. i have to bring it up to operating temp to drain the oil. i have to use an oil extractor because my oil drain plug isn't removable w/o raising the ft of the engine. then i'd have to realign it. so i use the oil extractor.

 

[Alwhite00]

Re: Winterizing without removing Thermostat?

I always remove my t-stat - C'mon, It's a 9/16 with a ratchet - 2 bolts. What does it take, 2 minutes? At least you know you are getting antifreeze through there.

LK

 

[ziggy]

Re: Winterizing without removing Thermostat?

It's a 9/16 with a ratchet - 2 bolts. What does it take

+ a torque wrench to retighten proper, a new gasket ya gotta get + some gasket sealer (hitach etc). takes me more than two minutes for sure.

At least you know you are getting antifreeze through there.

agreed...the proper way to introduce anti freeze imho..

 

[Alwhite00]

Re: Winterizing without removing Thermostat?

+ a torque wrench to retighten proper, a new gasket ya gotta get + some gasket sealer (hitach etc). takes me more than two minutes for sure. agreed...the proper way to introduce anti freeze imho..

For what it's worth - I have NEVER torqued a thermostat housing on any vehicle I have worked on and never had one leak. Probably done 60-80 of them in my lifetime.

I agree, You do need a gasket and scrape the old one off, I will revise my original 2 minutes to 5 minutes.

LK

 

[thumpar]

Re: Winterizing without removing Thermostat?

I have never removed my thermostat to winterize. Just drain the water out. I bet the mix of antifreeze and whatever water will freeze before my air will.

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

I'm still afraid of residual water laying in a water jacket somewhere. I pull the t-stat and fill with -100 antifreeze. At least whatever is left after draining will have antifreeze mixed with it. How do you know that all the water is out after draining all drains and pulling all hoses?

 

[Bondo]

Re: Winterizing without removing Thermostat?

I'm still afraid of residual water laying in a water jacket somewhere. I pull the t-stat and fill with -100 antifreeze. At least whatever is left after draining will have antifreeze mixed with it. How do you know that all the water is out after draining all drains and pulling all hoses?

Ayuh,.... If ya know, 'n understand yer motor, With the drain plugs out, the holes poked, 'n prodded,.....

Gravity insures it's Drained, Completely...

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

Ayuh,.... If ya know, 'n understand yer motor, With the drain plugs out, the holes poked, 'n prodded,.....

Gravity insures it's Drained, Completely...

You know, I am not an idiot. I am a mechanic by trade. Not a marine mechanic, and I am not claiming to know everything, but a 4 cycle water cooled engine, is a 4 cycle water cooled engine. I have torn down many an engine. After draining blocks, pulling water pumps, and pulling heads there is almost always SOME residual water. I have pulled heads, and when on the bench, I have had water leak out. Not alot, but still some water. Is there a difference, in the way marine heads are cast, as opposed to their automotive counterparts, that insure the water jackets dont have any nooks that could trap water? Just because I am not a moderator, doesnt mean I am an idiot. I have to say, the block would be competely drained, but my concern would be the heads. My next concern would be condensation. In closing, Filling up the water jackets, with GOOD MARINE antifreeze, rated for -100, would insure protection against trapped water freezing, plus most GOOD MARINE antifreeze have rust inhibitors, to at least slow down the process, unlike the RV antifreeze sold at wal-mart, which is meant for water systems, not engine antifreeze.

 

[wellcraft-classic210]

Re: Winterizing without removing Thermostat?

All good points.

Another one up for debate that I beleive to be true is ;

If a little residual water is left in the bottom of a pocket and it does freeze it will tend to expand / move into the open water pocket and not develop enough pressure / strength to crack the block.

When a water pocket is full and the ice forms its a much different story as it has no place to go / develops massive pressure and then soomething cracks.

And here is what I do;
I pull all my drain plugs on my 88 Merc 5.0 and then dump some antifreeze in all the hoses that go to the t-stat housing -- including the one to the water pump on the engine and especially the one to my outdrive to protect the power sterring cooler. I do this after the original water in the engine has stopped flowing and I watch/ listen to ensure the antifreeze does flow out of each drain point. I can do this without pulling the t-stat housing and using the antifreeze takes less than 10 additional minutes. It may be overkill but its one less thing to worry about over the long VT winter.


And yes Blue Light Special -- It sometimes seems people are overcritical on this site-- Sort of reminds me of being the newest helper at the old time gas station. But the learning that can be done here is invaluable if you can put all that aside. After all how often do you find really good mechanics that have really strong people skills.

 

[CHARGER2]

Re: Winterizing without removing Thermostat?

You know, I am not an idiot. I am a mechanic by trade. Not a marine mechanic, and I am not claiming to know everything, but a 4 cycle water cooled engine, is a 4 cycle water cooled engine. I have torn down many an engine. After draining blocks, pulling water pumps, and pulling heads there is almost always SOME residual water. I have pulled heads, and when on the bench, I have had water leak out. Not alot, but still some water. Is there a difference, in the way marine heads are cast, as opposed to their automotive counterparts, that insure the water jackets dont have any nooks that could trap water? Just because I am not a moderator, doesnt mean I am an idiot. I have to say, the block would be competely drained, but my concern would be the heads. My next concern would be condensation. In closing, Filling up the water jackets, with GOOD MARINE antifreeze, rated for -100, would insure protection against trapped water freezing, plus most GOOD MARINE antifreeze have rust inhibitors, to at least slow down the process, unlike the RV antifreeze sold at wal-mart, which is meant for water systems, not engine antifreeze.

If blocks and heads were cracking left and right due to residual water, either Merc would issue a service bulletin, or this forum would be well aware of the issue. Draining is fine. Like Bond-o said, prod the holes.

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

If blocks and heads were cracking left and right due to residual water, either Merc would issue a service bulletin, or this forum would be well aware of the issue. Draining is fine. Like Bond-o said, prod the holes.

Your right. If Blocks and heads were cracking, left and right, Im sure Mercruiser would release a TSB. My point is, the block will drain, no problem. Assuming the engine is sitting level, front to back, and side to side, I would think the block and heads would drain completely. But how are YOU sure all the water is out of the head? And I am not saying partially filled water jackets, I mean portions of water jackets completely filled due to gravity, or perhaps some restriction. I just think it is quite a gamble, just to drain the water, and do nothing else, especially when you cant see inside. Antifreeze, to me, is cheap insurance, and I am just asking how you know for sure that your good. By theory, everything should drain, but are you sure?

 

[wellcraft-classic210]

Re: Winterizing without removing Thermostat?

If the passages are blocked to the point of not draining then they would most likely be blocked to the point of no cooling in that portion of the engine and also to the point where antifreeze wont be able to enter.



That said -- you have some opinions of some very experienced people ( myself excluded as I am a rookie compared to some of these guys ) -- perhaps its just time to do what you feel most comfortable with.

 

[BajaDan]

Re: Winterizing without removing Thermostat?

I'm good with just draining the block, manifold and hoses and then poking around in the holes to make sure they aren't blocked. Like a few others on here have said, "air doesn't freeze." At least not on this planet... Any residual water left will be minimal and have plenty of water jacket to expand into.

 

[Another retired guy]

Re: Winterizing without removing Thermostat?

I'm going to add an opinion - it's not mine, it's from the owners of a local highly respected, family run ( 65 years ) marina. They Winterize hundreds of boats up here in the frozen north and they always drain first then flush with antifreeze. They tell me that you can never be 100% certain that there isn't some water somewhere in the engine. Maybe overkill, but I'm happy to leave my boat with them.

 

[BRG25]

Re: Winterizing without removing Thermostat?

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

If the passages are blocked to the point of not draining then they would most likely be blocked to the point of no cooling in that portion of the engine and also to the point where antifreeze wont be able to enter.



That said -- you have some opinions of some very experienced people ( myself excluded as I am a rookie compared to some of these guys ) -- perhaps its just time to do what you feel most comfortable with.

What if the restriction happens after the cooling water has passed through, or gravity, or air lock. Too many variables to gamble against. The local Mercruiser dealer removes the t-stat when they winterize, and on outboards, they flush with antifreeze, very similar to what Another retired guy says HIS marina does.

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

I'm going to add an opinion - it's not mine, it's from the owners of a local highly respected, family run ( 65 years ) marina. They Winterize hundreds of boats up here in the frozen north and they always drain first then flush with antifreeze. They tell me that you can never be 100% certain that there isn't some water somewhere in the engine. Maybe overkill, but I'm happy to leave my boat with them.

My point exactly! I just wanted to know, "How do you know for sure, that all the water is out?"

 

[BlueLightSpecial]

Re: Winterizing without removing Thermostat?

Enjoying the show? LOL!