does thermostat open?

David F wrote: Someone should come up with a temperature controled electrical outlet that switches on once the temperature falls to a set point.

They did... www.xtremeheaters.com

5 minutes to install in a skiboat: TOPS!
Kicks on at 40degrees F and off at 45degrees F and keeps your engine safe as long as you have electricity plugged in to it.

I sell the heck out of them.

Tom

I want to say we used exactly 3 gallons as well in the '88 351.

Tim D wrote: The T-stat is where water comes out of the engine, not "enters in the engine".

yes that's right, that's why it can and will trap air in the top of the motor unless it is open.

M3Fan wrote: The air pocket theory may be more relevant in a pressurized cooling system like a car's, not in a RW cooling system.

I don't usually jump in on engine topics, but this is one I know something about. I've probably drained and filled in excess of 10,000 engines (put myself through the first 5 years of college working in a radiator shop). I can say from experience that all engines will get an air pocket if you fill them with a closed thermostat in place. This is why you "burp" a cooling system, and then top off the coolant level.

I have my doubts that the air pocket would make much difference in terms of winterizing a boat, but then again, I don't live in a cold climate. BKH

Hey guys, thanks for all the input...I think. Yes, the engine is stone cold and the block, manifolds, and j-pipe were all drained. Cold and empty system. Never started the engine, just poured antifreeze in the RWP hose into thermostat housing.

It sounds like the system is filled with antifreeze. I am still going to run the engine tomorrow (after collecting the antifreeze from the valves...liquid gold!) for fogging reasons. If I have a thermostat gasket in the basement I am going to pull the stat and fill it that way. I know it is a pain in the a$$ and probably a waste of time, but oh well. I have done it both ways and never had a problem. But if I have a gasket, that is what I will do. I was listening to the weather and next saturday is supposed to be 60 degrees. Heck, I may REWINTERIZE next weekend. Need to break out the drysuit.

Thanks for the input guys. I never thought about the air pocket thing but now aware.

Stay warm!

Chris:

There is no way that pouring in cool (not ice cold) antifreeze into a warm marine engine is going to crack anything. The operating temperature of 160 degrees or so is very low and not high enough to be concerned about thermal shock when adding antifreeze slowly via the RWP hose.

TRBenj wrote: M3Fan wrote: YES, the block fills when empty, not just the manifolds, whether it is warmed up or not, whether the Tstat is open or closed, the damn thing FILLS UP. It does not run dry until the T-stat opens. Well that answers my question. Like DavidF, my engine is usually warm when I pour in the antifreeze. Glad to know I could drink another beer before backfilling and not worry about filling just the manifolds.

if your getting the engine hot draining it then pouring cold fluid back into it that's real stupid and your just asking for problems and a cracked block.

M3Fan wrote: YES, the block fills when empty, not just the manifolds, whether it is warmed up or not, whether the Tstat is open or closed, the damn thing FILLS UP. It does not run dry until the T-stat opens.

Well that answers my question. Like DavidF, my engine is usually warm when I pour in the antifreeze. Glad to know I could drink another beer before backfilling and not worry about filling just the manifolds.

the only issue you can have is that you can create an air pocket in the block if the t-stat is closed.

If the engine is cold, you drain the block, remove the hose from the topside of the RWP it will fill the block but it also can create a air pocket as well. that's why I like to remove the t-stat and pour it in there, I've even gone as far as running the motor with the upper t-stat housing and t-stat removed to circulate it to remove and mix the green car anti-freeze, the RV/Boat stuff I don't

79nautique wrote: wrong, it will feed the exhaust manifolds constantly and very little if any at all will go into the block. Drain the block remove the t-stat housing and t-stat pour in the antifreeze and be done with it. This crap about sucking it up and doing this and that is a big waiste of time, waistes more antifreeze, takes longer and doesn't do as good a job. Your a$$uming that the block has 100% antifreeze in it when you see it come out of the exhaust at the transom and in fact it's not it's deluted antifreeze and you'll use twice as much as needed. Bullsh*t way of doing things and I can careless what all you other's think that do it that way and have for years. do it that way and leave it outside up north and you'll be buying a new block come spring time.

I agree with your (and DavidF's) winterization technique, Chris- I do the same. The question is if the block is drained and refilled when it is cold, is it full of antifreeze, or did you simply fill the manifolds instead?

For those who use toxic (regular green) antifreeze, what is the proper procedure come spring? I know that the A/F is drained before starting the motor- should the motor be filled back up with water? If not, then the motor would be running dry until it gets up to temp- a$$uming the thermostat opens to allow water into the block

PCM makes no reference to the thermostat having to be open when filling the block with antifreeze. PCM simply states to elevate the RWP output hose higher than the thermostate and pour in the antifreeze. This is precisely what I do each year and never have had a problem with the block filling with antifreeze. So, I suppose it is possible that the circulation pump pumps against the the thermostate AFTER pa$$ing through the block.

However, in the process of fogging the engine and getting the fuel stabilizer to the injectors, the engine is always warm when I pour in the antifreeze. Whether the thermostate has time to close or if the cool antifreeze would abruptly close the thermostate, I have no idea.

What I do know is that the engine accepts the antifreeze and I am not loosing it out the exhaust manifolds as I leave the exhaust manifold plugs out and would surely see antifreeze pouring into the bilge if this was the case.

With all that said, I am going to agree with Chris and say that using the RWP and sucking in the antifreeze seems like a big ha$$le, waste of antifreeze, and totally off handed way of achieving an otherwise simple task. But, I do not know if such a method would be detrimental or not...depends on how well it is done.

I would *think* the hot metal block will transfer enough heat to the T-stat to open it up.

you changed the conditions no one said anything about draining the block first, if you do then you better fill it back up before you start the motor or your going to create a big air pocket in the block and have very little antifreeze/fluid if any at all will be present in the block and it all will be pumped out the exhaust leaving the block without any coolant.

water is constantly circulating in the block if the engine is running t-stat open or closed, when the t-stat opens then the path of least resistence allows it to flow throught to the exhaust manifolds and out while the cold water goes into the circulation pump and through the block and not the exhaust manifolds that's why the extra hole is in the lower t-stat housing. when the t-stat is closed there is more resistance in that hole than there is in the top half of the t-stat housing thus the flow goes to exhaust manifolds because there is no pressure there, thus the path of least resistance. when the t-stat opens it creates more pressure in the upper half of the housing and there is lower pressure at the little hole in the lower housing caused by water leaving the block and out the exhaust now the path of least resistance is in the little hole which is now seeing a vaccum created by the circulation pump.

wrong, it will feed the exhaust manifolds constantly and very little if any at all will go into the block.

Drain the block remove the t-stat housing and t-stat pour in the antifreeze and be done with it. This crap about sucking it up and doing this and that is a big waiste of time, waistes more antifreeze, takes longer and doesn't do as good a job. Your a$$uming that the block has 100% antifreeze in it when you see it come out of the exhaust at the transom and in fact it's not it's deluted antifreeze and you'll use twice as much as needed. Bullsh*t way of doing things and I can careless what all you other's think that do it that way and have for years. do it that way and leave it outside up north and you'll be buying a new block come spring time.