72 Avanti with GM 350 still overheating with all new cooling system componets.

[Jim S]

OK, I installed a brand new aluminum radiator, new water pump (and 180 thermostat) and an electric fan enclosed in a shroud that covers the radiator.  I flushed the system until all the rusty water was clear.  I run the engine and she still got hot up to 240 on the guage.  I shut it down and let the fan run.  (the fan kicked on at 160).  It go so hot the lover radiator hose blew of the water pump as I  walked by and my back was scaulded with second degree burns that landed me in the hospital burn ward.  I'm deeply disapointed in this car and don't know what to do next to get it to run cooler.  My 87 with a 305 had all the same new componets and it never got hotter than 150 degrees even in heavy traffic on a 90 degree day! 

[mfg]

5 hours ago, Jim S said:

OK, I installed a brand new aluminum radiator, new water pump (and 180 thermostat) and an electric fan enclosed in a shroud that covers the radiator.  I flushed the system until all the rusty water was clear.  I run the engine and she still got hot up to 240 on the guage.  I shut it down and let the fan run.  (the fan kicked on at 160).  It go so hot the lover radiator hose blew of the water pump as I  walked by and my back was scaulded with second degree burns that landed me in the hospital burn ward.  I'm deeply disapointed in this car and don't know what to do next to get it to run cooler.  My 87 with a 305 had all the same new componets and it never got hotter than 150 degrees even in heavy traffic on a 90 degree day! 

That’s terrible about your burns!!

A ‘72 Avanti would normally have a small block 400 CI engine… Did someone change that out for a 350?

All else being equal the 400’s tended to run hotter.

I swear by an engine driven viscous fan inside a full fan shroud… but that’s me!

Take care!!

[ronmanfredi]

6 hours ago, Jim S said:

OK, I installed a brand new aluminum radiator, new water pump (and 180 thermostat) and an electric fan enclosed in a shroud that covers the radiator.  I flushed the system until all the rusty water was clear.  I run the engine and she still got hot up to 240 on the guage.  I shut it down and let the fan run.  (the fan kicked on at 160).  It go so hot the lover radiator hose blew of the water pump as I  walked by and my back was scaulded with second degree burns that landed me in the hospital burn ward.  I'm deeply disapointed in this car and don't know what to do next to get it to run cooler.  My 87 with a 305 had all the same new componets and it never got hotter than 150 degrees even in heavy traffic on a 90 degree day! 

Jim,  Here are my thoughts on where you are.  First, you want to set the electric fan turn on temp at about 180-190, turning it on before the thermostat opens does nothing.  It should also come on with the A/C if you have one.  Next, I'd remove the thermostat and run the engine without it and see if the problem still occurs.  If so, and assuming the water pump is good, then you have a blockage of rust in the engine block or a leaking head gasket or cracked head.  There is a tool available that can detect for a blown head gasket/cracked head by detecting exhaust gasses coming out of the radiator cap area when running. (I'd check for that with the thermostat removed so you are fighting the thermostat).  If there aren't any exhaust fumes in the water, then a blockage in the engine block is a probability. If this is true, then you can remove the rear most freeze plug on one side of the engine block and get as much of the rust out of that side of the engine.  Install a new plug and then do the other side of the engine block. 

[Gunslinger]

Was the lower radiator hose changed?  If it’s the old one the inner spring could have rusted away (or a new hose missing the spring)…and the hose is collapsing under vacuum and acting as a coolant blockage.  Another possibility is a wrong or defective radiator cap.  If your car has a closed system and a cap for an open system is there coolant will not return to the radiator.  If the cap cannot hold pressure it will run hot.

Also…was the system burped after being flushed and refilled?  There be an air bubble blocking coolant flow.