My car runs at 220 degrees with both fans on, I'm running a 180 thermostat, 176 degree fan switch at is still runs 220. I also have a manual fan switch for the second fan. I already took out the a/c condensor, new 15lbs radiator pressure cap, running a 50/50 coolant water mixture, and the air dam is still in good condition. Why can't it go below 220. The only time the temp goes down is when i'm rolling down a hill at idle. If I change the coolant to water mixture to 30/70 will it help to cool the temp down. Also I noticed that my top radiator hose is puffed up (expanded from normal position) is this normal? And when racing down the 1/4 the temp seems to rise about 10 degrees. What can I do to drop my temp?

1988 Iroc-Z 5.7 tpi
Hooker Super Comps (Shorties)
AFPR, K&N, MSD 6AL, Ram air
Best time 14.09@97mph.

 

Sounds like there may be a restriction in the radiator... if your
t-stat is open and water is flowing to the radiator, AND there is
a restriction it might cause the upper hose to balloon.

I replaced my radiator and immediately saw cooler temps, and
even cooler when i started using GM-Dexcool.

Also, another thought, is there any air trapped in the system?

by the way, my 88 iroc convertible was originally sold at the
dealership in honolulu.