First 409

[Impala62]

Include it please.

 

[Croshd]

Are you using a thermostat? If so, what temperature is it rated at? The reason I ask is a thermostat will provide a restriction, slowing the coolant flow. Also, what ratio of water to antifreeze? Too much antifreeze won't dissipate the heat as well. Are you running a fan shroud? What fan are you running, with or without a clutch?

I am using a 160° high flow thermostat right now. I have a six blade fan with a 409 fan shroud I am running about 60% water 40% antifreeze I am using a clutch fan that has been tested that was original to the car. The motor has about 2000 miles on it when I did the motor. I also rebuilt the water pump.

 

[Jim Sullivan]

I am using a 160° high flow thermostat right now. I have a six blade fan with a 409 fan shroud I am running about 60% water 40% antifreeze I am using a clutch fan that has been tested that was original to the car. Some motor has about 2000 miles on it when I did the motor. I also rebuilt the water pump.

Next question I would have, when is the car running hot or overheating? Probably should have asked previously. I don't have any experience with high flow thermostats, I run a regular thermostat. I believe it is a 160 degree, cheap two core aluminum, fan shroud, 18" six blade clutch fan, 409 shroud and the engine runs 175 degrees while moving and may get up to 210 stopped in traffic on a hot day. Immediately cools back down to 175 once I am moving again. Pretty much the same set up as you have except the radiator and high flow thermostat.

 

[Croshd]

You have a good point about the thermostat. I used it with a different radiator I had and it seemed to work for that one. I have not tried to go back on the smaller slow thermostat. Do you have AC on your car cause I have AC and I have the big condenser in the front of the radiator. I am pretty sure if I didn’t have the condenser it would be fine. But I am trying to keep the A/C but it may have to go if I can’t figure it out.

 

[Impala62]

What temperature does it go to and when? My GS 455 would go 210-215 idling in hot weather but never actually overheated. Could it be as simple as a radiator cap not holding pressure?

 

[Impala62]

How did you determine the coolant was passing through the radiator too fast to cool it down?

 

[Croshd]

Well I was getting up to 210 with out A/C on I have replaced everything this my second brand new radiator and so far it is doing much better but the weather has not been that hot either. So far I have not seen it get past 190 but this s little traffic and about 70°. But it seems like every time I am off the weather is either raining or it cool out. I am running an AC Delco 13 pound radiator cap right now. It is not boiling out of the radiators. I am hoping to get out this Saturday supposed to be a warm day.

 

[Jim Sullivan]

You have a good point about the thermostat. I used it with a different radiator I had and it seemed to work for that one. I have not tried to go back on the smaller slow thermostat. Do you have AC on your car cause I have AC and I have the big condenser in the front of the radiator. I am pretty sure if I didn’t have the condenser it would be fine. But I am trying to keep the A/C but it may have to go if I can’t figure it out.

No a/c on my Impala.

 

[Croshd]

I didn’t put it on mine,not even sure when but looks like an older unit. Pushes real cold air I will say that. Like said if I can’t get this temp down where I want it will be removed.

 

[Impala62]

Close inspection of the under side of the 62 reveals rust in the rockers. Structurally compromised to the point high hp is not an option until this is addressed. Looks like I’m putting it on the rotisserie after all. Rear wheel tubs need replacing as well. Floors not too bad but might as well replace them while I’m at it. Good news is the body sheet metal needs very little work. Guess I replace body bushings and brace interior and start cutting. Any good videos out there on this work on these Impalas? They are put together a little different than I’m used to.

Phil