The Stovebolt Site Forums The Shop Area Engine Shop Overflow tank

I was wondering what everyone was using as an overflow tank. The 1946 truck with a 1961 261 leaks antifreeze out the overflow drain after shutting it off. The temperature gauage does not get into the red. TIA

Hank

A 1946 didn't have an overflow tank. If it is puking coolant after you turn it off, you are overfilling it.

But he has a '61 261 engine. Did 1961 come with an overflow tank?

On my 51, 228 it needed an overflow because of the engine coolant level and running hot. I put one on my 302, but it never gets hot and coolant is about two inches below the radiator cap, therefore no need for me. ( Used the stock can type )

Let it puke out. It will find its own level. Normally it's 1 1/2" - 2" below the bottom of the filler neck - just enough to cover the cooling tubes.

I put this generic $15 version on instead of $140 can style. Function is all right, but not overly thrilled with the look. As others have said probably not needed anyway.

Overflow tanks allow the pressurized portion of the cooling system to fill completely with coolant, eliminating the air within along with greatly reducing the rate at which the coolant oxidizes/loses its additive package.

If you can keep oxygen out of the cooling system, in theory it will reduce problems. My heater core is above the engine water level and I like to keep the system 100% full of liquid, I added a simple plastic bottle on the back side of the radiator core support where it is out of site, works like a dream to keep the system full. My engine/cooling system never gets too hot, I have to block part of the radiator in the winter, stock radiator/fan/water pump/180 degree stat.

The original system didn’t have an overflow tank, but was available as an option or accessory. They’re out there but pretty pricey. Here is one from classic parts.

My ‘52 with a ‘59 235 runs with about a 1/4” above the radiator core. Any more it just pukes it out. I fully agree that a coolant tank is a good idea and one that I’m eventually going to install.

There are other options, some creative solutions are out there.

Ol' Roy's previous owner installed an overflow tank. It's on the firewall. I don't like the way it looks but it works so I left it.

Unfortunately for the previous owner, he used the wrong type of radiator cap so the coolant wouldn't return to the radiator when it cooled down.

If you're using a tank, be sure and use a modern style cap with a poppet valve.

My '38 with a '55 GMC 270 runs a non-pressurized system. I'm using a quart mason jar for my overflow bottle.

Phil - Just a note that ordering the same thing directly from Classic Parts 1941-54 Original Style Overflow tank kit (not through ebay) is significantly less expensive, although that doesn't include shipping.

There are also other sellers offering virtually the same kit for less than the ebay Classic Parts kit. I'd just suggest folks do some shopping around as there are some better possible deals for those wanting to save a little.

That is pretty cool. I don't know if I can get to the bottom of a JD bottle and still be able to install that nicely.

This has been talked quite a bit over the years. This discussion leads to another:
Previous discussion

Can you tell me what level do you keep the coolant in the recovery tank?
It’s installed just like one shown in your post and for a 216 engine.

An inch or so above the bottom when the engine is cold. Leaves room for expansion and still keeps from sucking air back in as the engine cools down.

Here’s what I did. Wanted it to have the vibe of something farmer-fabbed back in the day. “Suction” function of it works really well.

It’s an old freezer jar and a repurposed fire extinguisher bracket.