Radiator flush
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you CLEAN the cooling system well the next time you change coolant, use a good grade of ethylene glycol coolant, and mix it ONLY with distilled water, you shouldn't have to flush it in the future (as long as you change coolant every 3-4 years, depending on use). The key is getting your entire system cleaned out WELL to start.
For a 1975 C3, install a 180*F thermostat...unless you live in a super-scrutinous emissions control state. Then, you will need to have all the stock equipment installed; and I assume that means the same thermostat (emissions are reduced by running the engine hotter at idle) which was a 195*F item.
P.S. The 195*F stat will probably not cause your engine to run much warmer than the 180*F stat, unless you have upgraded your radiator to increase cooling capacity of the system. But, Chevy engineers decided that a 180*F stat was optimal when the V8 was born in the mid-50's; and the reason the stat temp changed was purely due to EPA regulations. Hence, my suggestion...
For a 1975 C3, install a 180*F thermostat...unless you live in a super-scrutinous emissions control state. Then, you will need to have all the stock equipment installed; and I assume that means the same thermostat (emissions are reduced by running the engine hotter at idle) which was a 195*F item.
P.S. The 195*F stat will probably not cause your engine to run much warmer than the 180*F stat, unless you have upgraded your radiator to increase cooling capacity of the system. But, Chevy engineers decided that a 180*F stat was optimal when the V8 was born in the mid-50's; and the reason the stat temp changed was purely due to EPA regulations. Hence, my suggestion...
Last edited by 7T1vette; Jul 12, 2018 at 10:45 PM.
