Overheating Issue with new 350 sbc

84ChevyFloridatruck

New member
May 5, 2019
2
3
Hi, looking for some insight. I have a fresh 350 sbc, gen 1 that is overheating above 210-230. I have a new high-flow pump, all new hoses, new 180 thermostat, and new 3-row aluminum rad. Also note a new flex fan without a clutch. I'm not trying to overthink it, just doesn't make sense. Also ordered a new temp gauge (auto gauge)to ensure temp is accurate.
 

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Clutch

New member
Apr 15, 2019
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In my experience a clutch fan cools better. I just went threw this with my K30 and attributed the problem to the fact that I was running pulleys and brackets from a car the truck series pulleys are different diameters to cause the components to spin at different speeds
 

blk7gxn

New member
May 8, 2019
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Sometimes too if the flow rate is so fast its not having a chance to cool down in the radiator.
 
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Jun 23, 2020
14
1
las Vegas
Use a infared thermometer to measure the temperature drop between the inlet and outlet side of the radiator. if they are close in temperatures, you might be flowing through the system too fast like was mentioned above. You might have to install a restrictor plate at the inlet. My problem was the heater core was more free flowing than the radiator. so the water would move through the heater core and not the radiator. Path of least resistance. I put a restrictor in the heater core line and the temps came down.
 

Kiwi Clint

New member
Jul 11, 2020
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Auckland, New Zealand
Have you checked your thermostat ?? If coolant is traveling too fast, it doesnt spend enough time in the radiator to actually cool down. I run a 180 degree thermostat, and always drill a 1/8 hole in the very outer edge of the brass flange, to stop air becoming trapped and it also lets a small constant flow of water through the system. I suggest removing your thermostat and checking to see that it opens, by bringing it to the boil in a saucepan of water on your kitchen cooktop. As it reaches its correct operating temp, you will see it begin to open. Good luck .
 

Kiwi Clint

New member
Jul 11, 2020
3
1
Auckland, New Zealand
Hi, looking for some insight. I have a fresh 350 sbc, gen 1 that is overheating above 210-230. I have a new high-flow pump, all new hoses, new 180 thermostat, and new 3-row aluminum rad. Also note a new flex fan without a clutch. I'm not trying to overthink it, just doesn't make sense. Also ordered a new temp gauge (auto gauge)to ensure temp is accurate.
 

Kiwi Clint

New member
Jul 11, 2020
3
1
Auckland, New Zealand
Just a little advice, or rather a warning. The flex fan you have installed might look very nice , but there is NO WAY i would ever run one of those on any of my cars. Gradually over time the stainless blades work harden, due to their flexing as rpm,s get higher, and then become brittle, and are very prone to flying apart.
I have personally had 2 fail, with one sending a blade straight through the panel steel of my hood, and the second one destroyed an expensive radiator. These could do severe damage if you are working in the engine bay when one fails. There are one piece moulded plastic type flex fans that may not look as pretty, but seem to last ok. I currently run one of these on my streetrod, but my 83 pickup runs the original steel blade with no electric fans, and never overheats.
 

CTH AUTOMOTIVE

New member
Aug 10, 2020
4
1
CTH AUTOMOTIVE
What Clint says about the T stat. test it or probably just get a new one. I've had several defective ones lately...Very frustrating. If the 180 degree t stat doesn't open till 200....