Running Warm

rowdy1 wrote:Put an electric fan on the condenser "pushing". Add a simple relay that turns the fan on when the compressor clutch gets power. I would add a 3 position switch so that I could operate the fan independently. You would be surprised what a little airflow would do for temps.  Do you have a fan shroud? Get one if you don't. A fan shroud will direct the air being pulled by the fan through the radiator instead of just moving it around under the hood. I live in central FL, if you are having heat problems this time of year in FL. You may as well park that thing for the next 6 months. IT HAS NOT BEGUN TO GET HOT YET! My 1978 F150 w/ .060 over 460 stays cool, 175deg. w/ a two row aluminum radiator and a single shrouded 16'' electric fan on a thermostatic switch set to come on @ 185 deg. I also have a 10'' electric fan, as mentioned above installed on the condenser.

SLord82 wrote:A shroud is very important to ensure the fan is pulling air through the radiator and not around it. As I recall this isn't the first time you've brought up cooling issues and I believe people mentioned the shroud before. I think I even posted some craigslist links to fan shrouds for sale. Don't start replacing random parts until you have the current cooling system setup properly.

Doug Rahn wrote:Are you using the water pump backing plate between the timing cover and pump? Leaving that off can drastically reduce the efficiency of the pump to push water through the system.

rowdy1 wrote:Increasing water pump speed will not improve cooling unless the radiator is actually cooling the water. In fact the radiator does not "cool" the water, the air flow does. The faster the water moves throught the radiator, the less time the air flow has a chance to remove the heat. If the water going in the radiator is 205 deg and the water coming out is 190 deg the motor will never run 180 deg.  PUT A SHROUD ON THE DAMN THING.

Super Snake Steve wrote:I alway thought that water pump only go's bad when it starts leaking unless it was so old that the  impeller rusted away other that it either works or leaks and would still cool the same just that the bushing seal started leaking and you would change the pump out if it was mine and I never had the pump off I'd pull the pump check for backing plate and install new pump and work my way out from there shroud new hoses and high flow  thermostat make sure the  radiator  was flowing good and like I said before your timing can help keep it running cooler while  cruising or idling with added timing from the vacuum can

DFI429 wrote:A couple thoughts:

- The heater core introduces more surface area for coolant to eject heat (temp drop with valve open)
- Thermostats can, will, and have been bad out of the box, like other parts in our hobby..
- Is the radiator confirmed to be not plugged in any way?
- The shroud is more important than many realize or admit..

To your question of water flow - the pump maintains a constant recirculating flow into the front of the block when the tstat is closed, returning back to the pump through the small hose out the front of the intake.  When you open your heat valve, coolant splits and also takes the long route through the heater core and returns to the pump, inter-mixing with the flow back into the block.  When the tstat opens, there's big flow into the radiator for cooling, returning via the lower hose.  Under heavy load, with the heat on, you have coolant effectively having three routes flowing at once, although the path of least resistance applies, preferably radiator

FSU_Bronco wrote:I saw someone posted about a high flow thermostat, that could help, I know the thermostat has to be partially working as the top hose is getting hot.
When A high flow thermostat made for High volume water pumps work with a non high volume water pump? What is the ideal temp thermostat I should put in place?

It is a new Aluminum radiator so I don't know how to confirm it but when I shut the truck off and run my hand over the fins it feels to be evenly the same temp.

I order a shroud and it will be on by the end of the week I hope.

FSU_Bronco wrote:Installed a super cooling shroud today for the 78-79 series trucks. It is 4-3/4" deep, covers most of the fan. It did improve the running temp with the heater valve open. Just driving on a test drive I was seeing 183-185, down from 188-190. When I close the heater valve I am still seeing it raise into the 200's. It drops back down pretty rapidly after the open the valve back up.




Should my next step just be thermostat, or should I also do the water pump? If thermostat, is there a recommended brand? I read a lot of terrible reviews on the Mr Gasket High performace models, seemed many of those never worked or failed at a high rate.

Pull out the thermostat and boil it on the stove with an accurate thermometer in the pot and note were it opens. I have seen quite a difference between stats that are rated for the same temperature when cooking them in the same pot. Some open sooner and sometimes more then others even when they are rated the same.

cool40 wrote:Pull the pump and make sure the plate is on it.