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Help! Cooling System Question

Drwhitesr

Active member
Joined
Mar 19, 2017
Messages
31
Location
Davenport, Florida USA
Corvette
1980 C3 Corvette Red Coupe
I had an anti-freeze leak on my 1980 Vette. Heat core leaking. (That was fun to replace). I have now replaced the radiator and pressure cap, water pump, thermostat, all belts and hoses and hose clamps, heater flow control valve and new anti-freeze. When running, the temperature stays at about 200 to 205. I used a temperature gun to confirm the engine temp. Gauge is accurate within reason.

After running the car then shutting down, the car burbs about a pint of coolant out of the coolant system. Shows up on the ground near the heater core hoses. I used a pressure tester and cannot produce the leak with the car sitting in the shop. I tested the pressure cap and it holds 16 pounds of pressure. With all of that said, here is the question, would it be normal for the radiator to run low about a pint. It seems that if I leave the coolant level low, it does not loose any additional coolant, but leaving the coolant system low on coolant does not seem like the right answer. Thoughts anyone?
 

dougelam

Well-known member
Joined
Jul 19, 2011
Messages
453
Location
Michigan
Corvette
2002 Roadster
When you say "by the heater hoses" did that mean at the firewall?

A closed cooling will equalize it self after 1 cycle
Too much and it fills the reservoir when hot and at cap regulated pressure
Not enough it will draw it from the reservoir as it cools


Sent from my SM-N920P using Tapatalk
 

Drwhitesr

Active member
Joined
Mar 19, 2017
Messages
31
Location
Davenport, Florida USA
Corvette
1980 C3 Corvette Red Coupe
When you say "by the heater hoses" did that mean at the firewall?

A closed cooling will equalize it self after 1 cycle
Too much and it fills the reservoir when hot and at cap regulated pressure
Not enough it will draw it from the reservoir as it cools


Sent from my SM-N920P using Tapatalk


The anti-freeze is dripping on the ground near where the heater hoses exit the bottom of the car. Could be running down the frame rail. Hard to tell.
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
The anti-freeze is dripping on the ground near where the heater hoses exit the bottom of the car. Could be running down the frame rail. Hard to tell.



You need to find that coolant leak, it shouldn't be hard to find with that much coolant on the ground. Always trace to the highest point of any leak.

Do you have a surge or overflow tank on the vehicle for the radiator?
 

Wayback

Well-known member
Joined
Aug 14, 2006
Messages
562
Location
S-NJ
Corvette
93 Ruby Aniv roadster/6spd
Theres the surge/overflow tank with the cold level.its a little overfilled. if it aint leaken there its proably a loose hose clamp. Pressure testing the system while its cold sometimes wont work since the thermostat is closed & the heater control valve needs vacuum to open.Not my vette but its similiar to c3's,my old 68 didn't have a overflow tank,I did add 1.
181817_Engine_Web.jpg
 

Drwhitesr

Active member
Joined
Mar 19, 2017
Messages
31
Location
Davenport, Florida USA
Corvette
1980 C3 Corvette Red Coupe
Theres the surge/overflow tank with the cold level.its a little overfilled. if it aint leaken there its proably a loose hose clamp. Pressure testing the system while its cold sometimes wont work since the thermostat is closed & the heater control valve needs vacuum to open.Not my vette but its similiar to c3's,my old 68 didn't have a overflow tank,I did add 1.
181817_Engine_Web.jpg

I have the same tank in my car as the one in your picture
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
Thanks for your thoughts. You would think it would be easy to find the source of the leak, but yet it is driving me nuts.


If you have a/c like the vehicle in the pictures see if the coolant coming out of the evaporator drain tube.
 

Drwhitesr

Active member
Joined
Mar 19, 2017
Messages
31
Location
Davenport, Florida USA
Corvette
1980 C3 Corvette Red Coupe
If you have a/c like the vehicle in the pictures see if the coolant coming out of the evaporator drain tube.

That would mean that the new heater core is leaking correct? I hope that is not the case. Putting the new heater core in was not fun.
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
That would mean that the new heater core is leaking correct? I hope that is not the case. Putting the new heater core in was not fun.


Yes, if coolant is coming out of the evap drain tube then there is a problem in that area. The drain tube should be above the drip area you were describing. If you find coolant there make sure you follow up the firewall and engine area to make sure that the leak isn't external.
 

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