Cooling at idle/low rpm issues

[matt69]

I have a mildly built 302 with a hd 3 core radiatior, fan shroud and mechanical fan. I run at about 170-180 when cruising down the road, but at idle and creeping through a parking lot or trail the truck will hit 210 pretty quick. When I pick speed back up it will cool down to 180-190.

I am thinking that I need a electric pusher fan in front of the radiator, but have heard good and bad about doing this. I also don't want to mask a possible problem by adding the pusher fan. Is the pusher fan the correct fix?

Matt

Oh ya, I also have the inner fenders cut to allow air to get out.

 

[Smarty6]

Before you do anything that will cost you lots of money, do some general maintenace, flush the system and put in new fluids, check your hoses( they may be collapsed, and your thermostat.

 

[matt69]

I just put a new radiator in and new hoses. I did not put a new thermostat in, so I will try that tonight.

thanks

 

[68 Broncoholic]

If all else fails you can try a pusher fan. Worked well for me but I don't drive on the road much so slow cool trail running is what I was after.
I actually drilled and tapped the rear intake to allow water to flow back there.
To do this you need to add a T or Y into your heater hose like to complete the circulation.

 

[ugly74]

I'm gonna say you have an air pocket in the cooling system. my Mustang used to be real bad about that. it'd get hot at a stop, but if I raised the RPMs a little, it's drop back down. turned out to be an air pocket.
park it with the front end up (as far up as you can get it) , and let it idle with the cap off until it's up to temp. you may lose some fluid, but you will get the air out. most times, I'll "pump" the upper radiator hose too. squeeze slow, let go fast. I do that every time I have to refill the cooling system, and I haven't had any problems since.

 

[matt69]

Thanks for the tip Ugly74, I will try that tonight before I change the thermostat.

matt