Running Hot
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Elder User
Joined: Jun 2013
Posts: 685
Likes: 2
Running Hot
The truck
1979 f150
400 4bbl, intake, headers, and cam
NP435
NP205
Danna 44/ 9"
33" tires 4.56 gears
NO thermostat(yet)
Driving today and this evening I noted that the truck is running warmer than usual. I do not have an aftermarket gauge yet so I cannot tell you what the exact numbers are. Driving home in the cool night air, the needle held steady on "L" of normal. It did not overheat at any point and has never overheated on me.
When I parked in the driveway it was pushing some fluid into the overflow tank, but not much. Since it was hot I did not check the level(yet). The fan is working properly as far as I am aware. Although, it does not have a shroud.
How can I test my water pump? What other areas should I be looking at? The radiator has already been pressure tested.
1979 f150
400 4bbl, intake, headers, and cam
NP435
NP205
Danna 44/ 9"
33" tires 4.56 gears
NO thermostat(yet)
Driving today and this evening I noted that the truck is running warmer than usual. I do not have an aftermarket gauge yet so I cannot tell you what the exact numbers are. Driving home in the cool night air, the needle held steady on "L" of normal. It did not overheat at any point and has never overheated on me.
When I parked in the driveway it was pushing some fluid into the overflow tank, but not much. Since it was hot I did not check the level(yet). The fan is working properly as far as I am aware. Although, it does not have a shroud.
How can I test my water pump? What other areas should I be looking at? The radiator has already been pressure tested.
Postmaster
Joined: Sep 2013
Posts: 2,595
Likes: 5
From: Pasadena, Ca
The shroud is your problem.
I have told my story, but will tell it again...
I flushed my system 4 times, changed my water pump, and installed a new thermostat, and radiator cap. Drove it for 4 days. Mornings to work were fine, evenings were hot, then one day i drove downtown and boom! Blew the cap off the overflow.
I went home and figured out that i forgot to put the shroud back on. I put it on and run around O, rately to R.
I have told my story, but will tell it again...
I flushed my system 4 times, changed my water pump, and installed a new thermostat, and radiator cap. Drove it for 4 days. Mornings to work were fine, evenings were hot, then one day i drove downtown and boom! Blew the cap off the overflow.
I went home and figured out that i forgot to put the shroud back on. I put it on and run around O, rately to R.
Elder User
Joined: Sep 2012
Posts: 654
Likes: 2
From: The Lone Star State
If the vehicle is moving and getting airflow across the coils then there is heat transfer. If the vehicle is sitting still idling then there will not be enough low pressure area on the fan side to cause enough flow across the radiator.
The water less coolant has a much higher boiling point as well as other advantages but is expensive. Evans Waterless Engine Coolants - FAQs - frequently asked questions
If you can't find a shroud at your local salvage yard, LMC has them. I can't testify of the quality.
The water less coolant has a much higher boiling point as well as other advantages but is expensive. Evans Waterless Engine Coolants - FAQs - frequently asked questions
If you can't find a shroud at your local salvage yard, LMC has them. I can't testify of the quality.
Senior User
Joined: Jul 2011
Posts: 270
Likes: 0
From: North West
You need to run a thermostat in the 351m/400. The proper thermostat will have a "hat" on the bottom of it that blocks a bypass when the thermostat opens. If you have the wrong or no thermostat in it the coolant will go through the bypass at all times not just when cold which can cause overheating.
Click here for the proper thermostat
Click here for the proper thermostat
More Turbo
Joined: Mar 2012
Posts: 515
Likes: 8
As stated, I would definitely bet on the shroud. For the longest time, I thought the fan shroud was just to protect stupid people from getting their fingers chopped off, but mechanical fans actually rely on the fan shroud to help direct the air. If you were to install an electric fan though, you can do without the shroud.
I MIGHT have a shroud, but I can't remember if it's the one from my 79 or the one from the 86 I got my motor from. I'll check when I get home tomorrow though.
Nice truck btw, sweet color and lift, looks just right.
I MIGHT have a shroud, but I can't remember if it's the one from my 79 or the one from the 86 I got my motor from. I'll check when I get home tomorrow though.
Nice truck btw, sweet color and lift, looks just right.
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Elder User
Joined: Jun 2013
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As stated, I would definitely bet on the shroud. For the longest time, I thought the fan shroud was just to protect stupid people from getting their fingers chopped off, but mechanical fans actually rely on the fan shroud to help direct the air. If you were to install an electric fan though, you can do without the shroud.
I MIGHT have a shroud, but I can't remember if it's the one from my 79 or the one from the 86 I got my motor from. I'll check when I get home tomorrow though.
Nice truck btw, sweet color and lift, looks just right.
I MIGHT have a shroud, but I can't remember if it's the one from my 79 or the one from the 86 I got my motor from. I'll check when I get home tomorrow though.
Nice truck btw, sweet color and lift, looks just right.
Thanks for the complements on the truck!
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Thread Starter
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Elder User
Joined: Jun 2013
Posts: 685
Likes: 2
You need to run a thermostat in the 351m/400. The proper thermostat will have a "hat" on the bottom of it that blocks a bypass when the thermostat opens. If you have the wrong or no thermostat in it the coolant will go through the bypass at all times not just when cold which can cause overheating.
Click here for the proper thermostat
Click here for the proper thermostat
That part looks identical to what I have sitting on the workbench. Does the spring loaded side face towards the block, or towards the hood?
More Turbo
Joined: May 2007
Posts: 622
Likes: 2
From: Phoenix, AZ
Here is a picture of the one I'm doing, I paid less than$30 at the u pull it yard.
And the radiator is and American Eagle from eBay.
Senior User
Joined: Jul 2011
Posts: 270
Likes: 0
From: North West
Install as pictured in the link(spring down) you can see the small "hat" that comes down from the bottom that blocks the bypass. If you look down in the thermostat hole you can see the bypass.
Postmaster
Joined: Sep 2013
Posts: 2,595
Likes: 5
From: Pasadena, Ca
The picture posted by EP145 is still a shrouded electric fan.
A fan does not cool your engine! It sucks air through the radiator, cooling the coolant inside. Without a shroud, your fan will merely pull in warm engine air from the engine, just mix it around. All force is removed from pulling through the radiator.
A fan does not cool your engine! It sucks air through the radiator, cooling the coolant inside. Without a shroud, your fan will merely pull in warm engine air from the engine, just mix it around. All force is removed from pulling through the radiator.
More Turbo
Joined: Mar 2012
Posts: 515
Likes: 8
The picture posted by EP145 is still a shrouded electric fan.
A fan does not cool your engine! It sucks air through the radiator, cooling the coolant inside. Without a shroud, your fan will merely pull in warm engine air from the engine, just mix it around. All force is removed from pulling through the radiator.
A fan does not cool your engine! It sucks air through the radiator, cooling the coolant inside. Without a shroud, your fan will merely pull in warm engine air from the engine, just mix it around. All force is removed from pulling through the radiator.
That being said, I would highly recommend going electric, and going with a 93ish-98ish Lincoln Mark VIII fan. They also came in like 97-98 Lincoln Continentals. That's what I'm running in my truck. I have a 3 row aluminum radiator for a 351 (like pictured above), and the Mark VIII fan (looks like the one above), and it will keep my diesel at 190-200 all day long.
I think my fan was like $25 or $30 bucks at the local you pull parts place, and you want to run a nice big relay. I would advise using one of the gray 70 amp Ford relays, easily found in the fuse box under the hood of any/most Ford Focuses (maybe other models, not really sure).
More Turbo
Joined: Mar 2012
Posts: 515
Likes: 8
I will also add that I've had a taurus efan in the past, and the Mark VIII fan blows the taurus one away... Pun intended lol seriously though, that Lincoln fan could probably suck a small child up against the grille
