Engine Header Tank--You are not going to believe this one and a what is it? :

1911tex

Member III
When my "new to me" E35 Was on the hard for a bottom job...I asked if they would flush the cooling system and add 50/50 marine antifreeze on my M25...it was time. I reminded them to bleed the air out of the system or the engine would overheat. The mechanic told me they did. When the boat splashed yesterday, I cranked...started right up and began to heat to 200 (never before). I shut it off, called their mechanic who did the flush, and he spent 2 hours trying to figure it out trying ways to bleed the bubbles out of the cooling system. Nada. Unhappy (being polite here) as it was getting dark and very frustrated, I started looking around. I opened the starboard cockpit lazarette and noted a radiator cap on a 12" or so square aluminum box with 2 hoses leading to the engine cooling system...I asked what is this for? He looked and did not know. I opened the cap and it was bone dry. I put 1/2 gal of 50/50 antifreeze...cranked the engine and it topped out at 180 degrees with one hose turning warm and the other cooler. Left for 30 minute dark engine trip to my marina (not an ideal time); running lights worked! Engine locked on 180 for the trip, never missed a beat. Now I need to change oil again due to the 200 degree overheat (changed the oil 3 weeks ago). Does anyone know what that radiator capped box is? A hot water heater of some sort? How does it heat the clean hot water with antifreeze in it?...had to leave due to night time and will go back mañana to take another look. Sorry for being so ignorant.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hi,
Sorry you had to go thru that!! The mechanic should have known better, in my opinion. That black aluminum box is critical to your cooling system, and needs to be filled with coolant / water mixture to 1" below the cap. If he didn't do that, it would explain the overheating, as your coolant level would have been too low. In not sure running for a bit at 200 degrees requires another oil change. In my opinion if the oil looks fine, feels appropriately slippery between your fingers and doesn't smell burnt, I would think it's fine but on the other hand an oil change is cheap and might help you sleep better.
Frank
 

Parrothead

Member II
Tex, that is a header tank. It is a fill point and reservoir located at the high point of the cooling system. In many cases the factory engine fill point is lower than some of the plumbing going to and from the water heater so a header tank is provided. Also, it's time for a different mechanic. He should have recognized it immediately. What else doesn't he know?
 

1911tex

Member III
Frank/Parrothead: I can only hope this informs another boat owner about the header tank...so they can be prepared...I was so happy to get my boat home to its slip and with a new bottom and rudder restore...the repair marina did a first class job. Your information is incredibly important to those, like me, who have no clue. I will inform the repair marinas service manager, better yet, owner. Yes, it will make me sleep better with the oil change. Great thanks!
 

Christian Williams

E381 - Los Angeles
Moderator
Blogs Author
He's not a mechanic. But it does illustrate how workers are overestimated by boat owners who don;t bother to know their boats (and who would not have even known to look at the temperature gauge as Tex did). For example, our local high-priced mechanics (CC Marine, MDR) are well respected yet "prefer not to work on old Universal engines." Why? Because they sell Yanmar and Volvo and their guys don't have experience with our engines and their various marinizations. A tractor mechanic in Iowa would know more than they do.

Used to be there were itinerant boat mechanics wandering the yards. No more, at least not around here. Old boats mean old guys, and old guys are a dying breed. Wait, that came out a little wrong. But, uh, well, never mind.

The good news is that our engines, even the yacht versions, are designed for simple maintenance and troubleshooting, and that we all quickly become experts on our own particular installations.

Here is a truth that every hand here has come to understand: trust nobody to do it right. Routine stuff we could do ourselves is handed off to unsupervised apprentices, or just gets lost in the shuffle and not performed at all--except on the bill. That's why we shrug and learn to do it ourselves.

I'm having my dripless shaft seal replaced next month by a gold-plated yard. I can't do it myself. But Do it wrong and the boat sinks. So I will be doggone sure to interrogate the yard, inspect their work, and read the installation literature myself. I'll also personally remove the hoses necessary for access. All while paying full retail.

So: trust, but verify. Доверяй, но проверяй! That's the politics of dealing with boatyards -- and Russians.
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Well said, Christian. With time and diligence, one can learn alot about boat and diesel engine maintenance, even without formal mechanical training. There are good books available to help - - my favourite being Nigel Calder's Boatowners Mechanical and Electrical Manual. This website has also really helped many of us with sound, common sense advice. It's also important to know one's limitations, and get reliable professional help when needed.
Let's all keep up the good work in keeping this website functioning so well, and keeping our boats in good shape.
Frank
 

Parrothead

Member II
The first header tank installation I saw was on an Islander Freeport 36, hull #1 in roughly 1976 so it's nothing new. I have one on my current boat too, necessary when I converted from raw water to fresh water cooling. Drawing of my current system is attached. It's not to scale but the relative elevations are approximate.
 

Attachments

Kenneth K

Sustaining Member
Blogs Author
Just an amateur's opinion, but I don't think a momentary 200 deg overheat necessitates an oil change. The Universal manual shows normal operating temp range of 165-190 deg. Probably more harm done operating the engine below 165 than up at 200 for a few minutes.

20200315_223350.jpg

Also, I believe the header tank is a function of the hot water heater. It handles the expansion of the extra coolant in the HW tank/lines and provides a high-point for bleeding the system.

More on the topic; https://ericsonyachts.org/ie/threads/32-3-coolant-recovery-tank.16449/
 
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Parrothead

Member II
Ken, if I may clarify a little:
  • Also, I believe the header tank is a function of the hot water heater when the water heater is mounted higher than the engine.
  • It handles the expansion of the extra coolant in the HW tank/lines and provides a high-point for bleeding the system. True but should not be confused with an expansion/recovery tank which is completely different. A header tank is under positive pressure during engine operation, regulated by its pressure cap. In contrast, a recovery tank is vented, normally at ambient pressure during engine operation and at negative pressure during engine cool down (coolant recovery function).
 

goldenstate

Member III
Blogs Author
The first header tank installation I saw was on an Islander Freeport 36, hull #1 in roughly 1976 so it's nothing new. I have one on my current boat too, necessary when I converted from raw water to fresh water cooling. Drawing of my current system is attached. It's not to scale but the relative elevations are approximate.
I'd like you to come over and Auto-Cad my electrical system for me. I can't bring myself to spend the time to learn a proper drawing program and am envious of those who have...
 

Parrothead

Member II
I can't bring myself to spend the time to learn a proper drawing program and am envious of those who have...

It is a surprisingly helpful tool in boat ownership and maintenance. I always encourage people to get out of their comfort zone and challenge themselves and this can be a great way to do just that. Like most powerful computer programs the learning curve can be prolonged, perhaps a great way to spend your time during self-quarantine or shelter in place. Also, know that if not used often your skills will get rusty.

The program I use is TurboCAD. Its drawing tools are very similar to AutoCAD at a fraction of the cost and writes files in a variety of formats including .dwg (AutoCAD), .dxf (Drawing Exchange Format), .pdf and .jpg to name a few. I've attached a screenshot of a TurboCAD workspace

TurboCAD Workspace.jpg
 

Kenneth K

Sustaining Member
Blogs Author
Ken, if I may clarify a little:
  • Also, I believe the header tank is a function of the hot water heater when the water heater is mounted higher than the engine.
  • It handles the expansion of the extra coolant in the HW tank/lines and provides a high-point for bleeding the system. True but should not be confused with an expansion/recovery tank which is completely different. A header tank is under positive pressure during engine operation, regulated by its pressure cap. In contrast, a recovery tank is vented, normally at ambient pressure during engine operation and at negative pressure during engine cool down (coolant recovery function).
No arguments here. However, it seems Ericson's design (unlike your diagram) was that the pressure cap necks on BOTH the engine manifold AND the header tank have overflow lines to the recovery tank. While this might seem redundant, it allows, as is my current situation, normal engine operation with the hot water tank deactivated (lines to H20 tank not connected).
 

toddster

Curator of Broken Parts
Blogs Author
Just an aside: the overflow tank only works if you have a properly-working double-action cap on the pressure tank. For some reason, these caps seem to have a short lifetime on my boat.

My '71 boat apparently never had an overflow tank. IDK what they were thinking. I moved the heat exchanger up next to the (added) water heater, so it itself is the header tank. And I added an overflow tank up there. On the E29, this allowed me to restore the engine cover, which was raised to accommodate fresh water cooling, to the designed flat configuration that doesn't interfere with the quarterberth cushions.
 

billie williams

Member II
Tex, that is a header tank. It is a fill point and reservoir located at the high point of the cooling system. In many cases the factory engine fill point is lower than some of the plumbing going to and from the water heater so a header tank is provided.
I am in the process of replacing the heat exchanger on my 1984 E30+. My mechanic (who I really like, btw) is telling me that the header tank is not needed because the hot water heater is not higher than the factory engine fill point. He suggests that as long as we are replacing the heat exchanger, we remove the header tank from the system.

My hot water heater is in the main salon, port side, seat locker. Was that the original design on the E30+ ?

My current thinking is to leave it as it was designed - I've never had an overheating issue with the boat. The heat exchanger is being replaced because it's leaking.

Any other input appreciated!
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Our 1984 E30+ has the hot water heater in the port cockpit locker above the fuel tank. I don't know if that was the original location or if it has been moved there by a previous owner.
Frank
 

Afrakes

Sustaining Member
I am in the process of replacing the heat exchanger on my 1984 E30+. My mechanic (who I really like, btw) is telling me that the header tank is not needed because the hot water heater is not higher than the factory engine fill point. He suggests that as long as we are replacing the heat exchanger, we remove the header tank from the system.

My hot water heater is in the main salon, port side, seat locker. Was that the original design on the E30+ ?

My current thinking is to leave it as it was designed - I've never had an overheating issue with the boat. The heat exchanger is being replaced because it's leaking.

Any other input appreciated!

Leave the expansion tank right where it is.
 

Afrakes

Sustaining Member
Never had an engine temp over 180. My expansion tank is mounted above the hot water heater. The hose from the tank is routed above the tank and then down below the coolant filler. Never a problem.
 
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