Possible high temp issues when stopped

[Trappey74]

My 74 302 has a Howe aluminum radiator in it. Not sure about the thermostat degree but I'd imagine it's stock. When I drive it down the highway the temp gauge hangs around between 170 and 190. Stop for a while and leave it running and it will move up to around 200+/- Drove 15 minutes down the highway the other day and stayed around that 190 range. Turned it off and ran in somewhere and crank back up after 3 or 4 minutes and it's around or above 210 but starts to fall once I get back on the road and air moving through. Do I need a different temp thermostat?

 

[Broncobowsher]

No. Thermostat sounds good.

Have a fan shroud, that fits and functions correctly? What fan are you running. Pictures do better then a description.

The temp rise when you shut the engine off is normal, called heat soak. The metal in the engine is hotter then the coolant. It has to be in order for the heat to transfer to the coolant. Shut the engine off and the combustion stops, but the metal is still hot. Hotter than the coolant, which has stopped flowing. The metal cools off and the coolant warms up. As soon as you start the engine the coolant starts flowing again and goes back.

 

[B RON CO]

Hi, X2. If you drove around all day over 40 MPH you wouldn't need a fan. Just the airflow would keep you cool. At slower speeds the fan is pulling in the needed air. If you have a shroud the fan should be 2/3 in and 1/3 out. There are different size spacers to move the fan in and out.
Any time someone mentions running hot I say check the ignition timing. Improper timing will make an engine run hot. Good luck

 

[Pa PITT]

...Our Bronco were not designed to pull the air through the radiator.
So as some one said make sure you have shroud .. Then look in the vendor catalogs there are several other other items designed to push the air through the radiator .
One covers the open hole right & left of the hood latch.
Another blocks off beside the radiator filling that gap. I put that 2 inch foam insulation for pipes in the winter in mine ... AIR JUST SUCKED IT OUT in no time so you know there is a lot of air going by. figure out some way to make them stay in place.
Even block the air flow from under the radiator. But fundling the air through the radiator is what your after.
... Then there is another route of getting the hot air out from under the hoods. I expect a short hood scoop might do that .& there are several other ways.
Again look at the vendors catalog.

 

[Trappey74]

I do have a shroud and not sure exactly the fan set up on it. I'll get pics later today and get yalls opinions

 

[edmedlin]

I run an HD 3 core aluminum radiator and two electric fans, one mounted at the driver's side top and the other passenger side bottom. The top fan is set to come on at 175degs and the other at 190. Both come on whenever I turn on the AC. My temps, even on a hot day with AC on, never go above about 200degs in city traffic. 90% of the time the temp is right at 190. I run a high horsepower big lift and duration cam 302 with about 385hp. What I noticed right away was the lack of all the heat when I open the hood. My old mechanical fan setup would blast me with heat when I opened the hood. I have no shroud really. Each fan is mounted directly to the radiator. They cover about 3/4s of the radiator surface. Mounting one at the hot water "in" and the other at the return gives maximum cooling for the surface covered. I only had about 4" clearance between the radiator and the pulleys, so there is no room for a shroud, even with the lowest profile fans I could find. I also run Dart Pro-1 heads and ceramic long-tube headers which also seem to retain less heat under the hood. Cooling a higher performance engine on these EBs can be a trial and error thing. My mechanical fan and shroud combo was a very tight fit and the fan would occaisionally hit the AC compressor pulley. A spacer would put it much too far into the shroud and very close to the radiator (even with the stock radiator) hindering cooling performance. The photo shows how tight it is under there.

 

[jw0747]

200-210 degrees is not a high temperature issue.

 

[broncnaz]

200-210 degrees is not a high temperature issue.

X2 On top of that do you know if your gauge is accurate could be a little off and your not that hot. Also if you let it idle and when it gets to 200 degrees try upping the idle speed a little most likely the temp will come down.
You may need a different fan. Flex fans do wear out so to speak as time goes by they may not flex back enough at low speed to pull as much air as they once did. I would also look at fan Dia. Try to make sure its as big as possible maybe leave about 1/2 clearance between it and the fan shroud.