Hey guys,
I have a '93 LT1/T56 in a '72 Chevy Vega. I am running a manual transmission radiator with an 18lb radiator cap. The car doesn't have an overflow tank at this point in time. The cap is the new, and the radiator was recently tanked. I have the steam line entering into the radiator at about the same height as factory.

I am losing about half a gallon of coolant per day. I can see that it's coming out the vent hose on the radiator. I've been diligently refilling it, but I know this isn't normal. Can anyone help me pinpoint the problem? Am I running the wrong cap pressure? Need a pressurized overflow tank with a lower pressure cap?

Thanks,
Colin

 

Its perfectly normal to lose coolant when you don't have a reservoir (overflow tank). The purpose of the reservoir is to catch the coolant that normally flows out of the radiator cap when the coolant heats up and expands. If you had a reservoir, as the coolant cooled down and contracted, the resulting vacuum would pull the overflow out of the reservoir to keep the radiator full. But yours is blowing the coolant out on the ground when the coolant heats up, and sucking air back in when the coolant cools down.

 

Fred,
Thanks for the really quick reply. Should I run a pressurized reservoir or will any suffice?

 

No. You keep the 18psi cap, and use an atmospheric reservoir. The overflow tube from the radiator has to reach all the way to the bottom of the reservoir.

 

Fred,
Perfect! I'll look for a stock reservoir for my Vega. I'm sure one of the members on my site will have one. I appreciate the help.