Running a little too warm

[mgoodman]

1984 F250, 460, 4 speed - bought for my son for $700
new t-stat, water pump, flushed radiator, new water temp guage.

T-stat opens at 180*, I can tell by the sudden drop in water temp, but the temp rises and falls between 190* and 220* on a consistent basis and only when driving.

Out of ideas on why its running warm like this and seeming to rise and fall in temps. Any help is greatly appreciated.

TIA
Mike

 

[fatherdoug]

Is the level in the radiator ok? If so, the problem might just be due to air in the system. The air needs to be burped by parking the vehicle on a slope so the radiator is higher than the engine, then removing the radiator cap(while still cold). Run the engine up to temp with the cap removed. When the thermostat opens up, you will probably "burp" air out of the system. Depending on the level in your radiator, you might also lose some antifreeze when the air is displaced. Sometimes increasing engine rpms will speed the process, but you stand a bigger chance of losing some antifreeze out the top of the radiator. Also make sure your heater control is moved to "heat", so you burp any air out of the heat exchanger for the cab.

 

[mgoodman]

Great.. Will give that a try this weekend. I was thinking it was possible it was an air bubble... but, I was running out of other ideas as well.

M

 

[fatherdoug]

Oh, and welcome to FTF. I forgot to put out the welcome mat when I replied.

 

[Ridgerunner]

Welcome to FTF. Another tip I do when changing thermostats is to drill a very dmall hole in the flat part to help it burp also.

 

[fatherdoug]

Good idea! That also makes it a "failsafe" thermostat. The Robert Shaw thermostats have a little dimple built into the sealing surface to accomplish the same task.

 

[Ridgerunner]

Good idea! That also makes it a "failsafe" thermostat. The Robert Shaw thermostats have a little dimple built into the sealing surface to accomplish the same task.

Yeah the last time I did that I ran the drill bit through my leg while drilling the hole. Yes I was holding the thermostat, this time I will us my small vise.

 

[fatherdoug]

 

[mgoodman]

Thanks for the welcome guys.. if the air bubble trick doesn't work, maybe I will pull it apart and drill the hole in the t-stat.

Guess I should throw my intro into the introduction forum....

M

 

[Beach66Bum]

Welcome to FTF!