Cooling system forum
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Cross-Country
Joined: Nov 2014
Posts: 55
Likes: 3
From: Alberta
Cooling system forum
Hey guys,
I'll try and keep it short. I have a 79 supercab with a brand new 400 in it. I have about 2000km on the motor. I'm having troubles keeping the darn thing cool while towing or giving it some throttle. I Know it'll run hot, but not as hot as it is. I've put a lower thermostat in it, brand new rad and hoses, and heater core. I'm wondering how crutial the coolant mixture is? Its roughly half half, but I just used tap water from my farm, water that I wouldn't drink. how much does this affect the operating temp? And also, I had a hell of a time finding a fan shroud, the one I have currently sits about an inch away from the fan. Could that also be a problem?
I'll try and keep it short. I have a 79 supercab with a brand new 400 in it. I have about 2000km on the motor. I'm having troubles keeping the darn thing cool while towing or giving it some throttle. I Know it'll run hot, but not as hot as it is. I've put a lower thermostat in it, brand new rad and hoses, and heater core. I'm wondering how crutial the coolant mixture is? Its roughly half half, but I just used tap water from my farm, water that I wouldn't drink. how much does this affect the operating temp? And also, I had a hell of a time finding a fan shroud, the one I have currently sits about an inch away from the fan. Could that also be a problem?
Elder User
Joined: Jun 2011
Posts: 940
Likes: 4
From: Illinois
How high did you fill it? Should be about a half inch below full. My 360 runs hot when radiator is full cold. There are several threads about lower thermostat doesn't mean lower temps. Coolant needs to stay in radiator lower to get cooled. Sounds crazy to me but its true.
Postmaster
Joined: Nov 2011
Posts: 2,553
Likes: 10
Can you tell us about the radiator? Reason I ask is I had some issues with a new radiator on my 78/400. I put a new 3 core "extra cooling" on from the parts store. The standard radiator is 2 core.
Anyhow, I had a similar issue. Under high load in hot weather the temp would creep up. Towing or running 70 down the interstate for example. It did not overheat but seemed to be getting worse as the radiator got a couple years old. I guess those "3 cores" were pretty thin.
A 4 core Champion radiator fixed it. Good now.
Anyhow, I had a similar issue. Under high load in hot weather the temp would creep up. Towing or running 70 down the interstate for example. It did not overheat but seemed to be getting worse as the radiator got a couple years old. I guess those "3 cores" were pretty thin.
A 4 core Champion radiator fixed it. Good now.
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
If the timing is overly retarded the engine will run hotter and creep up under load .. Also did you remove the egr plate when you rebuilt it ? and are you using the stock duraspark II distributor ? If yes then you will need to recurve your distributor ..
Are you running an auto transmission ? If so are you using a radiator with the transmission cooler built in ?
A transmission temp gauge and an external tranny cooler are big pluses if your doing any long term hauling with an auto transmission ..
Are you running an auto transmission ? If so are you using a radiator with the transmission cooler built in ?
A transmission temp gauge and an external tranny cooler are big pluses if your doing any long term hauling with an auto transmission ..
Cargo Master
Joined: Jul 2005
Posts: 2,309
Likes: 364
From: Kansas
first, how are you determining "running hot"...what actual temperature is your aftermarket temp gauge reading (with the factory gauge, it is impossible to tell).
When you say the shroud is 1 inch from the fan, are you talking about the clearance from the tip of the fan blade out to the lip of the shroud, or is the entire fan 1 inch from being inside the shroud opening? The fan tip to shroud clearance probably should be closer to 1/2"...and the fan itself should be somewhat centered or a little deeper within the shroud opening.
Also, you didn't mention if you are running a solid fan, fan with clutch, or flex fan...
When you say the shroud is 1 inch from the fan, are you talking about the clearance from the tip of the fan blade out to the lip of the shroud, or is the entire fan 1 inch from being inside the shroud opening? The fan tip to shroud clearance probably should be closer to 1/2"...and the fan itself should be somewhat centered or a little deeper within the shroud opening.
Also, you didn't mention if you are running a solid fan, fan with clutch, or flex fan...
Fleet Mechanic
Joined: Aug 2010
Posts: 1,574
Likes: 6
From: Cranbrook, Ont., Canada
Just a suggestion... the lower rad hose has a metal coil spring in it to keep the hosr from collapsing during acceleration. If it is not there the waterpump will suck enuff to collapse it. Sometimes we forget about replacing it or NOT putting it in when we replace the bottom hose. I have done along with a few of my buddies. lol Popa John.
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
Just a suggestion... the lower rad hose has a metal coil spring in it to keep the hosr from collapsing during acceleration. If it is not there the waterpump will suck enuff to collapse it. Sometimes we forget about replacing it or NOT putting it in when we replace the bottom hose. I have done along with a few of my buddies. lol Popa John.
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