Overflow/Expansion Reservoir
Thread Starter
Instructor
Joined: May 2018
Posts: 200
Likes: 25
From: Tennessee
Overflow/Expansion Reservoir
I have an aftermarket radiator in my 80 vette. Finally have been able to do longer drives so I filled up the reserve tank. I filled it up to cold, and after I got back and the car was hot, the water was still at the cold mark. Just got back a today after letting it sit for a week, the level has now dropped. Also, the fitting on the tank is about 3/8 and the aftermarket radiator is about a 1/4. Previous owner had the clamp tight. I'm starting to wonder if the tank is working correctly. How is it supposed to work? Do I want a tight connection between the radiator and tank. No visible leaks. Thanks
Melting Slicks
Joined: Sep 2016
Posts: 3,004
Likes: 104
From: NC
The idea of the expansion tank is just that, when hot the coolant expands and it flows into the tank and when cools off vacuum will suck fluid back from tank.
Old cars just used to dump the fluid onto the ground.
The hoses do need to seal decent at both end, I usually have clamps on them.
I'd keep an eye on the level but bet it stabilizes since you said no leaks.
Old cars just used to dump the fluid onto the ground.
The hoses do need to seal decent at both end, I usually have clamps on them.
I'd keep an eye on the level but bet it stabilizes since you said no leaks.
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Race Director
Joined: May 2006
Posts: 18,742
Likes: 2,583
If the tank has a pressure cap on it you also appear have a pressure cap on the radiator. You either need a blank cap on the radiator or have to remove the center spring assembly so that it no longer acts as a pressure cap
Thread Starter
Instructor
Joined: May 2018
Posts: 200
Likes: 25
From: Tennessee
Huh funny you say that. Every time I open the radiator that’s water sitting in the cap area. On the tank, I just have a generic plastic cap, probably not the right one.
