Overheating II

[Anonymous]

Hi Everyone,

Well I fixed the overheating problem while it's running it barely gets above the first mark now. However when I stopped to get gas coolant was coming from the overflow and when I started it the guage was all the way to hot. I came down pretty quickly after I started it up. What could be causing it to get hot when it's shut down?

Bob

 

[MustangSix]

Heat soak. After you shut down all the heat is still being transferred from hot places to cooler ones. That's the job of the coolant. But it can cause the added expansion you see. That's why an overflow tank is a good idea. That way when the coolant finally cools, it gets sucked back into the radiator. Without it, the radiator sucks in air instead.

 

[Anonymous]

Thanks for the reply Jack,

Is heat soak something that I need to worry about or is it just a matter of installing an overflow tank to prevent coolant lose and getting air into the system? In other words will it hurt anything or is there a problem that needs fixed that causes heat soak?

Thanks again,

Bob

 

[MustangSix]

It can make a car hard to start on hot days. The fuel can evaporate from your carb or it can cause a vapor lock. It's tougher on carbureted cars than EFI ones because of that. Just putting on the tank will help head off a lot of problems.

A real effective solution is to have an electric fan run until the radiaor temp drops. The coolant will continue to circulate by thermal siphon. The drawback is you need a pretty good battery to handle the fan for the 5-10 minutes it sometimes takes.

 

[Anonymous]

When the radiator is filled full and you don't have an overflow tank, your radiator should eventually find level where it will not spit out any coolant after shutting down. The coolant expands pushing some out. When it cools back down, air is drawn back into the radiator. Do not top off the radiator, and it will find its level.

If you do not top off the radiator everytime and it continues burping fluid and the level gets low exposing a good portion of the tubes, then yes, something is not normal.

I think overflow tanks are one of the reasons that newer cars have fewer cooling problems. The overflow tanks minimize the amount of oxygen getting into the coolant. The oxygen increases the corrosion rate and helps consume the corrosion inhibitors. Coolant seems to last longer in newer cars despite neglect.
Doug