RADONE

iTrader: (1)

For some unknown reason the amount of coolant in my radiator is always about ½ pint short. The level is about ½ pint low if I check it and fill it after every drive. Even stranger, the radiator only needs about ¾ pint to fill it if I wait a month to check the level.

The reservoir appears to be at the correct level.
No signs of coolant on the ground or leaks from the block
No evidence of burning coolant. Exhaust is not visible at idle.

I am assuming if there is a leak at the block or if the engine is burning coolant at a rate fast enough to loose ½ pint in a couple hours, the fluid loss would not max out at ¾ pint after driving for a month.

When I previously experienced this exact problem with another GM vehicle; I borrowed a pressure tester to check for a leak at the top of the radiator. I thought the fluid loss was maxing out at ¾ pint because the leaking stopped after the water level fell below the hole in radiator. I also changed to a factory radiator cap thinking the auto parts store radiator cap was loosing fluid under pressure. Needless to say I failed to diagnose the problem.


I hope that someone is familiar with these symptoms and can help me solve this annoying problem.

Thanks

LS6427

iTrader: (2)

Get a new radiator cap.

.

99_LS1_WS6

iTrader: (5)

I agree try a new cap and see if that fixes the problem. The cap could not be letting it stay pressurized.

LaBLKv6Z

iTrader: (13)

Pressurize the system with about 16psi and look for where the coolant is streaming out.

wssix99

iTrader: (5)

New cap then pressure test. If you are holding pressure fine, then this may be your issue:

https://ls1tech.com/forums/general-m...ant-level.html