Coolant overflow hose

[Spiderbob]

i discovered some coolant underneath the car and traced it to under the overflow tank. I tightened the clamp and found that had worsened it. I had no more coolant in the tank then next time I drove it. ( I checked it before I drove it. The overflow reservoir was empty but the actual radiator was full. I removed the empty tank and filled it with water while plugging the drain hole and saw no leakage. But after replacing the hose I still detect moisture under the lowest point of the hose right below the reservoir where it turns toward the radiator about an inch below. What to do from here? I've searched for a replacement overflow hose but haven't seen one listed anywhere? Could I be over or under tightening the clamp? Is the hose just a standard one or do I need one that has a larger end to fit over the reservoir nipple underneath. Any insight would be appreciated.

[TX82FIAT]

I replaced the overflow hose with a standard hose from the parts shop for coolant. I can't remember to size hose only that it should be just big enough that you can get it over the nipple on the radiator and overflow bottle with a little pressure and a tight fit. I think it is a 12 mm hose so 1/2 inch should work if needed as the nipple and clamp will do the rest of the sealing. You are on to something, do not over tighten, it just needs to be snug as this is an overflow and not under pressure as the cap is designed to release pressure. The overflow is a critically important part of the cooling system. When the car heats up the coolant expands into the tank and when it cools it draws the coolant back into the system. Without the overflow hose and tank you will draw air back into the system and it will create problems.

[18Fiatsandcounting]

I'd also suggest checking again the connection for the hose at the bottom of the overflow tank. You could have a hairline crack that only opens up when you push or pull on that connection, such as like when you have a hose attached.

And there's nothing special about the hose, just standard coolant/heater hose that fits the connections on both ends. Make sure it isn't routed too close to the exhaust manifold.

-Bryan