Missing Engine Hose?

[gulfcoaster]

I've noticed after looking at some photos of ericson engines on Yachtworld that there is a hose that comes off the right side just under the coolant filler cap. I see a nipple but there is no hose here. We have a M-25 in our "87 32-3. What is it and where is it supposed to go?

 

[bayhoss]

It goes to a small plastic storage tank similar to that on an automobile. I'll be at my boat tomorrow, I can get a photo if you like.

Best always,
Frank

 

[rwthomas1]

That nipple just below the "radiator" or coolant cap is the overflow. Old cooling systems did not have an overflow, they had an airspace at the top of the cooling system that allowed for expansion in the closed system when the engine heated up. If over-filled, these systems would "burp" coolant when hot until there was enough airspace to accommodate the expansion. Then someone had the idea to allow the coolant to overflow into a bottle, filled from the bottom. This allowed the cooling system to be filled to capacity, as the coolant expands from heating up it moves into the overflow bottle, then when the system cools down it is pulled back into the system. This allows the cooling system to be filled to capacity with no airspace. I'm guessing if you open your system and look into the reservoir the coolant will be an inch or so down from the top. Thats the airspace. Your system is currently burping air, not coolant from a bottle. If you choose to add an overflow bottle, and its not a bad idea, make sure you have the correct coolant cap. The old style caps only have one gasket as they will not pull coolant back in when cooling off. The other reason there is an overflow is overheating, the bottle catches the coolant as it is pushed out. The bottle is not usually large enough to hold much coolant but caught early enough it will keep coolant from getting all over your engine room.

Hope this helps, RT

 

[Brian K]

Too Much is Not Good

Interesting topic. Last year I replaced the exhaust riser on my Universal M25XP (1988 E32-200) and all the hoses associated with the closed loop cooling system and therefore had to replace the antifreeze. The hose being discussed here goes to the overflow tank in the starboard cockpit locker. The tank was always dry and looked like it never had any antifreeze in it. Upon refilling the cooling system I thought it would be appropriate to fill the tank to the "COLD" level stamped into the side of the overflow tank. Great idea, until I opened the cap on the engine and all the fluid in the overflow tank came out. It turns out the overflow tank is higher than the fill cap on the engine so gravity allows the fluid to come out of the fill cap once the fill cap is removed from the engine. Should the tank be relocated to the engine compartment? Should it be lower than the fill cap on the engine? Or should I just leave it dry as it has been for the last 5 years?

 

[bayhoss]

Too Much is Not Good

There is more than one type of coolant overflow system. The simple gravity feed return system is the one that is being mentioned. That came first. All is really does is keep antifreeze from escaping into the water. It is supposed to be installed higher than the engine so that when the engine cools you can return coolant to the tank. The process starts when the engine overheats, pressure pushes the coolant into the tank where is stays. Once the the engine has cooled then you simply open the fill cap and gravity refills your system. The second type is a more complex system mentioned above. The explanation of how that system works is excellent and on the money. The major difference is that the second system actually refills the coolant in the engine by returning pressure when the engine cools. So, if you have a gravity feed system - put some fluid in the holding tank and don't crack the coolant cap unless you are low, or prepared for a spill.

Best always,
Frank

 

[rwthomas1]

Brian,
I'm willing to bet that if that overflow bottle was moved to a location that is level with or lower than the coolant pressure cap vacuum will pull coolant back in when the engine cools AND it will not overflow from gravity as it does now when the cap is opened. This is old tech, automobiles have had setups like this since the 60's. Never seen a setup in an automobile that was higher than the coolant cap.... RT

 

[Stu Jackson]

Our M25 didn't come with one. I added a simple small Rubbermaid bottle. The existing hose fit right into the opening in the top of the jar. It's a tad lower than the top of the exhaust manifold. Works "as advertised."

 

[Blue Chip]

empty bottle

I'm with you Brian. That bottle in our 1990 32-200 has never seen a drop of moisture in it for the past 20+ years. I have also opened the "cap" and even cold, fluid comes out. Working on the "if it ain't broke, don't fix it " theory. I have never touched, used, or had a conversation with that bottle again. I'm happy, and so is the engine. It's a head scratcher to me, but again.."IF IT AIN'T ETC ETC".

 

[Brian K]

Yes, I thought I was doing the right thing by adding coolant to the "COLD" level in the overflow tank. It's empty now, since I opened the coolant cap on the engine, and it's going to stay that way,,,,, for the next 20 years. Thanks for the feedback gentlemen.

 

[spencer]

I have the same set up with the bottom of the bottle above the top of the collant resevoir. My engine is a 1985 M-40. I finally figured out after reading the manual that the coolant level is supposed to be 1-1/2 inches below the top of the rim where the cap sits.If you fil the coolant above that level it just expands into the bottle when hot and runs all over if you open the cap when cool. So I learned just to fill to the 1-1/2 level and leave it be.

 

[mherrcat]

The manual is contradictory on how much to fill the manifold with coolant. The following from the Owner's Manual for the 12, 15, 18, 20, 25, 30, 40 & 50 engines:

The fresh water manifold on models 12, 18, 20, 25, 30 40 & 50 should be filled slowly to the bottom of the filler cap. A 50/50 mixture of fresh water and antifreeze solution is acceptable as an all weather coolant, eliminating the need to drain the fresh water system for cold weather operation or storage. A coolant mixture may change based on climatic conditions in your area. The rust preventive will aid in reducing rust formation if no antifreeze is used.

but later on...

FRESH WATER:

1. Coolant (fresh water with antifreeze) is introduced into the system from the coolant section of exhaust manifold by removing pressure cap and filling manifold tank to within one inch of lower rim of fill port.

Whichever way you do it, if your engine is not overheating it is probably fine...

 

[Emerald]

And this, boys and girls, is why I can't stress enough the value of good gauges and knowing what you're engine is doing when it's happy egrin versus wondering by the level in an expansion tank if something is amiss.. :0

 

[bayhoss]

In addition - the temp gauge is a darn sight easier to see when under way than a tank that's waaaaay underneath!!!

Best always
Frank

 

[rwthomas1]

There are merits to either method as long as the airspace doesn't present any issues such as overheating, etc. I prefer to fill completely and have the system push out and pull in coolant as the temperature cycles occur. This is a habit from working on automobiles, some are very finicky and will tolerate NO AIR whatsoever in the system.

When I purchased my boat there was no coolant in the overflow bottle so I added some. The level never changed, hot or cold, which left me scratching my head a bit. Turns out when the overflow bottle was manufactured the hose nipple was completely occluded and completely sealed! It had never worked as intended. I drilled it out and it has worked as designed ever since.

RT