Cooling System

[Leif A.]

When a '67 L79 with A/C is cool (before start up), what should the coolant level be in both the radiator and overflow tank. I know it sounds silly but I don't want to overfill or underfill before taking out for the first time in awhile. thanks.

[Ralph E.]

Re: Cooling System

When a '67 L79 with A/C is cool (before start up), what should the coolant level be in both the radiator and overflow tank. I know it sounds silly but I don't want to overfill or underfill before taking out for the first time in awhile. thanks.

Suggest you follow John Hinckley's method, works every time.

" the recipe is to fill the engine through the thermostat opening in the intake until the coolant level comes up to the top, then install the thermostat, gasket and housing/upper hose, and continue filling through the expansion tank until the tank shows half-full. Leave the cap off, fire it up and run it until the thermostat opens (upper hose gets hot right away), let it run for five minutes, and shut it down. When it cools, top up the tank to half-full, cap it, and you're done.

The air in the block has to have a place to vent as it's displaced by coolant when you fill; if there's no place for it to go (or the path is difficult), you wind up with a short-fill and air pockets."

[Duke W.]

Re: Cooling System

Do you have an owner's manual? It should say the expansion (not overflow) tank level should be half full when the engine is cold. The radiator should be full, but there is no access to check it. The coolant quantity is checked as above.

Duke

[Leif A.]

Re: Cooling System

gentlemen,thank you very much. Duke, I do have an owner's manual but this forum is so informative with real life experiences that I prefer to ask questions even after reading the manual.thanks, again.

[Leif A.]

Re: Cooling System

And, just as a technicality, the owners manual calls the expansion tank a "supply tank". But, I was wrong calling it an overflow tank...only human.

[Joe L.]

Re: Cooling System

And, just as a technicality, the owners manual calls the expansion tank a "supply tank". But, I was wrong calling it an overflow tank...only human.

Leif------


This is a common misnomer. I've heard the tank called all sorts of things but, correctly, it's a SUPPLY tank. All radiators have supply tanks but most are integral with the radiator. Some, like 63-72 Corvettes with aluminum radiator have no integral tanks and only use an external supply tank. A few have BOTH integral AND external supply tanks (e.g. 1969-72 big blocks with copper/brass radiator).

If you fill the tank more than half full, that condition will be very short-lived.

[Leif A.]

Re: Cooling System

Thanks, Joe (and, Duke)...half full it is!!

[Thomas N.]

Re: Cooling System

Or is it half empty?....I've had great results following the filling through the thermostat openings on a flush or new applications also.

[Leif A.]

Re: Cooling System

you say tomato, I say tomoto...who knows???

[Timothy B.]

Re: Cooling System

Leif,

One thing to remember is to re-check the coolant level the next day when the engine is cold, if the engine needs more coolant that's when to add it.

[Leif A.]

Re: Cooling System

One additional question...my radiator has a 15# RC-26 cap and my supply tank has a 15# RC-15...are these the correct caps? Again, mine is a '67 L79 w A/C.

[Timothy B.]

Re: Cooling System

Leif,

The radiator in the car can't be a original style Harrison radiator. There should only be a radiator cap on the supply/expansion tank and the RC-26 is the correct cap. Take a picture of the set up and post it so we can see what you have.

[Leif A.]

Re: Cooling System

I'll get a picture posted ASAP...thanks, Tim.

[Leif A.]

Re: Cooling System

Tim,

Let' see if I did this correctly...first attempt at loading and sending pics. Thanx.

[Leif A.]

Re: Cooling System

A few more...