overheating in 72' 250
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New User
Joined: Sep 2002
Posts: 5
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overheating in 72' 250
i have a 360 rebuilt the whole engine. M.S.D. ignition, holly carb. oversized radiator, high flow water pump, oil cooler,trans. cooler,R.V.cam.i took out the thermostat.as long as im driving the temp. stays at 185 to 190 degrees but if i let it idle the temp goes up to 200 to 205 degrees.what is the operating temp. for this truck and my cranking comp. pressure is 120 is that to low? i also have replaced all hoses and the heater core. 
Logistics Pro
Joined: Oct 2000
Posts: 3,960
Likes: 5
From: All over Texas
overheating in 72' 250
Don't worry about 200 or 205 degrees. These engines are meant to run at least that hot. Your compression sounds a little low for a new motor, but take a reading of all cylinders and then make a determination.
Elder User
Joined: Dec 2001
Posts: 800
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From: Ontario, canada
overheating in 72' 250
I'd start by putting the thermostat back in.
I know some guys will disagree with this, but the purpose of the thermostat is to keep the coolant in the engine long enough to warm up to the desired temp... but the flipside is that it also keeps it in the rad long enough to cool down. Dosen't always happen this way, but i have seen it in a marine engine with heat exchangers instead of rads and in a 64 chev pickup that i had as a teen.
I know some guys will disagree with this, but the purpose of the thermostat is to keep the coolant in the engine long enough to warm up to the desired temp... but the flipside is that it also keeps it in the rad long enough to cool down. Dosen't always happen this way, but i have seen it in a marine engine with heat exchangers instead of rads and in a 64 chev pickup that i had as a teen.
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
overheating in 72' 250
Ditto, put a stat in it. With a high flow pump and no stat you’re pumping too fast for the coolant to pick up the heat in the engine and to let it go out the radiator. Also, at higher rpms the pump will cavitate without the stat. This will cause the impeller to pit and erode. The orifice in the stat provides the right amount of restriction and backpressure for the cooling system.
Barry
Barry
