Overflow Tank Missing

My 1966 Mustang Convertible didn't have an oveflow tank. 289 CID small block Ford. It's standard on all late model vehicles, though. On drag strips and race tracks it prevents fluids from your vehicle from overflowing onto the race track, causing your own wheels to loose traction. This is exactly what I saw a Panoz have happen to it on Speed Channel this last Sunday at Laguna Seca, it overheated on track, lost its' coolant fluids and spun on its' own boil over fluids. There was a 'witty' comment from the announcer that the chief mechanic and crew chief would be quizzing the driver whether he ever checks the temperature gauge while driving. The purpose of the overflow tank is to recycle the antifreeze and coolant, saving 'money' and spins and the need to check the radiator fluid levels often. Summit and JEGS and others offer overflow tanks, which are not stock. I've seen them advertized on this BB in Parts For Sale. No, not necessary, but sorta nice to have. If you run her hard, fill up the radiator before taking her out again.

Your car needs an overflow tank to work properly. When the engine heats up, the water expands and no longer fits in the cooling system. So the radiator cap opens and allows the excess water to expand into an overflow tank. When the engine cools off, a partial vacuum is created, the cap again opens and water is sucked back into the cooling system from the overflow. Without such a tank, your cooling system will lose water each time you drive, and about the 3rd or 4th time, it will overheat. The overflow need not be a stock tank, but if its plastic, shield it from header heat, or it will melt. This happened to me in a 50 mile drive.

I have a stainless (Hall) overflow tank for sale. Bought it on eBay from some guy who thought it was the supply tank. It has a couple scratches so I don't want a lot for it. E-mail me at eric.tolnes@verizon.net

Eric

As of 10/30 tank has been sold, but if the deal falls through, I'll edit my post again to update. Tanks for your interest.

[This message has been edited by ETolnes (edited 10-31-2003).]

Thanks Eric. I still need the tank, so if the deal falls through, send me an email or call me at 973-879-3548.

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Originally posted by ETolnes:
I have a stainless (Hall) overflow tank for sale. Bought it on eBay from some guy who thought it was the supply tank. It has a couple scratches so I don't want a lot for it. E-mail me at eric.tolnes@verizon.net

Eric

As of 10/30 tank has been sold, but if the deal falls through, I'll edit my post again to update. Tanks for your interest.

[This message has been edited by ETolnes (edited 10-31-2003).]

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Jack,
I understand the theory of the system, but the previous owner changed the cap to a type that has a red pressure relief valve. This valve seemed to leak coolant rather than allow flow through the hose to the recovery tank. I have since replaced it with a conventional radiator cap. When I check the level in the expansion tank it is always down a few inches which tells me coolant is not transferring between tanks. I have removed and cleaned both tanks and installed new hoses, even reversed forced air in the recovery tank over-flow hose to verify coolant flow. Do I still have the wrong cap?
Thanks.

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Originally posted by jack deryke:
Your car needs an overflow tank to work properly. When the engine heats up, the water expands and no longer fits in the cooling system. So the radiator cap opens and allows the excess water to expand into an overflow tank. When the engine cools off, a partial vacuum is created, the cap again opens and water is sucked back into the cooling system from the overflow. Without such a tank, your cooling system will lose water each time you drive, and about the 3rd or 4th time, it will overheat. The overflow need not be a stock tank, but if its plastic, shield it from header heat, or it will melt. This happened to me in a 50 mile drive.

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Maybe not. First, US-made caps sometimes have extreme problems sealing to the expansion tank neck, possibly because Euro thermostats are slightly longer. Second, the base of the tank neck is usually horribly rough so it usually seals water but not the vacuum produced by engine cool-down.The 'normal' fix for both is to take the tank down to a radiator shop and have them desolder the stock tank-neck and attach a US-made substitute. This costs maybe $15. It's is important, since cap leaks not only can cause overheating, but the leaking water runs down the tank, down the inner fender panel and directly into a frame vent hole. There are no lower drains in the frame as-stock, so the water sits down there, rusting your chassis. Second chore: drill the recommended frame vent holes (rainwater also gets into those frame holes). Finally, the hose connection between tanks uses a 5/8" connection on one end and a 1/4" connection onthe other. Unless you have a custom made adapter, whatever kluge ("Kluge"- poorly thought out, makeshift device) was included to join the hose to the tanks is probably leaking under vacuum. On my car, the hose itself had split at the bottom, probably from header heat.

When I got my car it had no overflow tank. Due to the construction of the engine bay roll bar, bottles were moved around, and an overflow never hooked up, it just dumped out, right on the headers. When I first got it I noticed I could smell hot water sometimes when I'd let off the gas. That's when I discovered what was going on. I actually drove it like this for about a year and half, putting coolant in it about once a month. Real pain, but I was trying to be positive, and thought of it as an auto-flush feature, haha. I got it fixed finally, and it sure is much nicer not having to mess with that headache all the time.