Coolant Expansion Tank: Where to Buy ?

[NCboatrx]

correct. for a 2" truck filler neck.
Stan

[SV Demeter]

Thanks Stan. I am going back to my Napa and see what they can do.

[SV Demeter]

Giving Napa that part number did the trick. Got the right cap. Not sure why the first clown I spoke with there could not figure this out but thanks again Stan.

[gettinthere]

OK, I'm confused (surprised?)

I have a perkins 4.154. I also have a water heater that sits on a shelf above the engine. I have a common overflow bottle that is plumbed to the engine radiator pressure relief cap. I don't have an expansion tank as described here. I've had discussions about my radiator cap with TAD because I was loosing a bit of coolant. They never brought up an expansion tank, but they did say to not overfill the header tank, that is what was leading to my constant overflow of a small amount of coolant.

What am I missing?

Thanks

[Blue Stocking]

Originally Posted by gettinthere

OK, I'm confused (surprised?)

I have a perkins 4.154. I also have a water heater that sits on a shelf above the engine. I have a common overflow bottle that is plumbed to the engine radiator pressure relief cap. I don't have an expansion tank as described here. I've had discussions about my radiator cap with TAD because I was loosing a bit of coolant. They never brought up an expansion tank, but they did say to not overfill the header tank, that is what was leading to my constant overflow of a small amount of coolant.

What am I missing?

Thanks

I agree 100% with above. Have the same set-up on my Westerbeke W46- with nary a problem.

[SV Demeter]

Interesting. Everything I have read had led me to believe that doing what you guys have done can lead to air getting trapped in the cooling system with no way to bleed it out. All the engine and water heater manuals reccomend locating the heater below the cooling system cap or if that is not possible to add a remote header tank that is at the cooling systems high point so air can be bled from the system.

After reading the most recnent posts I am now thinking that perhaps in the case of the 4-154 this may not be needed. The reasoning here is that the coolant line that suppplies heat to the water heater is a relatively small bypass loop and that once the thermostat is opeed a relatively small portion of the cooling system is circulating through this loop. Thus any air trapped in this section only compromises the heat transfer occuring in the water heater and that this air will not go on to present problems for the cooling circuit of the engine.

Alas I have come this far and probably spent money I need not have but I will finish the set up as planned and see how it goes. Thanks again to all who have posted for your help.

[wolfenzee]

The coolant expansion tank on my boat is milky coloured plastic (about 2l)and is mounted on the bulkhead behind the companionway steps, I can see the coolant level from anywhere in the cabin (including the forward cabin).

[NCboatrx]

Originally Posted by SV Escape Plan

Interesting. Everything I have read had led me to believe that doing what you guys have done can lead to air getting trapped in the cooling system with no way to bleed it out. All the engine and water heater manuals reccomend locating the heater below the cooling system cap or if that is not possible to add a remote header tank that is at the cooling systems high point so air can be bled from the system.

Escape Plan, this is actually quite correct for 95% of installations. It is possible to get the cooling system working but this involves quite a bit of time to fill the system properly beacuse you can't pour water uphill. If the pressure cap / fill point is the highest point of the cooling system, everything will work well.

[wolfenzee]

The fill cap for the system I described is actually 2' above the top of the engine.

[gettinthere]

My pressure cap on the engine cooling system is about one foot below my hot water tank.
I also have a pressure relief recovery tank that is about 4" lower than the pressure cap. It's a standard automotive overflow tank. It is fed by a tube from the neck of the pressure cap. It receives overflow when the pressure builds up in the system forcing coolant out. It gets very little coolant.
Perhaps as a precaution, I should relocate it above the hot water heater.

[NCboatrx]

Gettinthere,
The plastic recovery tank has nothing to do with the cooling system that is under pressure and raising it wont make any differance. The reason that it gets little or no overflow is that your cooling system is not full. Thus the expansion of coolant that happens when it gets hot, stays within the cooling system. This could potentially lead to an overheat problem ans some coolant is expelled.
I assume (always a problem) that your installation is not new and has been working properly so as long as you keep an eye on it you should be ok. On a number of installations where there is enough capacity in the cooling system, keeping the coolant level about 1/2" below the filler neck seems to work.

[SV Demeter]

Relocating the overflow tank wont change anything as it only recieves coolant when the cap opens and expells excess coolant as mentioned.

I should have probably titled this thread Remote Coolant Header tank and not expansion tank. Of course now after hearing of all the folks who have set ups with heaters as the high point in their cooling system I am starting wonder why I am doing all this extra work.

[wolfenzee]

The disadvantage of the location of mine is that it takes up counter space in the galley....but being able to check it from anywhere in the boat (as well as fill it really easily) is worth it (counter space is a total of about 16 sq ft).

[ggray]

Very interesting to hear of other's installations and experience.

Here is my system:

Catamaran with typical engine in each stern. Came with 2 water heaters, each behind (slightly below) each engine.

Replaced both w heaters with single one on one side, but with 2 seperate heat coils inside. Water hoses from opposite engine have to be routed maybe 30 inches above pressure cap of that engine.

When I installed this W H, I made sure to fill complete system of this opposite engine.Never had any problem over the last 4 years I guess. However, I recently read an article by a respected expert who said that this would court problems unless there is an expansion tank w/fill at highest point of system, including lines.

I looked into available expansion tanks to do this, but finally decided to leave it as is. This thread convinces me that doing this is not too unusual or risky. I will need to make sure the system is kept full of coolant.

So...thanks!

[gtod25]

Hi NCboatrx or anyone else. Can you guide me to a source of those remote header tanks in the photograph.

Thank you

Gerry