The temperature, according to my gauge, in my 1980 F-150 Ranger XLT barely creeps up to the first line, making me suspicious that the thermostat is stuck open. The engine seems quite warm to the touch (at the valve covers). I will be travelling out of Labrador and picking up some parts. I was wondering what the recommended thermostat for our climate might be. We get quite cold in the winter. Only a few hot days in the summer. And we don't have lots of miles of roads here, so getting up to normal operating temperature is preferable. I'm not sure what degree therms are recommended for my truck.

 

The recomended thermostat is between 192 and 195 degrees per factory specs.

What is the first line on the gauge mean to you? These gauges are prone to interpretation and are not very accurate. Although they are better than a warning lamp.

This is my recomendation in how to read the factory gauge. Anywhere between the first line and the N and O in the word normal is optimal temps. Anywhere between M and L is safe for driving but the system needs to be checked, and anything above L you need to stop the engine and call a tow truck. This assumes that the sender and gauge is working optimal as well. It wouldn't hurt to check the thermostat in a bowl of water with a candy thermometer. Put the bowl on the stove and heat it up and see where the thermostat opens on the candy thermometer. You can also see if it sticks or opens at the wrong temps as well doing this. If in doubt replace it, but get a good quality one. You will have nightmares with cheap thermostats.

If the thermostat is good, replace the sender for the temp gauge. They get old and tarnish and wont read properly (read lower than they should) as well.

 

My guess is your not the original owner. If so, remove the thermostat and check the temp rating..........probably a 160....toss it and install a Robertshaw 180. It will move the needle to "R" in Normal.

 

If it is computerized, stick with the stock temp as fuel mixture is partly temperature dependant.

 

if its not coming past the first line you probably arent building any pressure in the system, check for leaks and replace the radiator cap. Does the overflow stay full?

 

Nope. Not the original owner. When I purchased the truck, I believe I remember the gauge getting up to where it should be. Seems to have changed since flushing the coolant and replacing it. Both the bottom and top rad hoses are hot after driving some time. The overfill has just a bit (1 inch) in there. I noticed that it took quite awhile to get any in there- like weeks.

 

fill the over flow, check the level in the radiator, replace cap.

 

If the coolant is at the right level ( 1 1/2" below the filler when COLD), then it's normal for the overflow tank to be empty when the engine is cold. If fully up to temp. then switched off, coolant will rise in the tank until the engine has cooled again & pulled it back into the radiator.

From 87 on, the overflow tanks were part filled when cold.

 

Just so you know, the pressure of the system has nothing to do with the temperature of the system. The pressure of the system just lets you run a higher temperature than 212F without boiling over. It also lessens the expansion that was talked about the previous post. If you only run a 7lb cap, the coolant will expand and contract dramatically during the heat and cool cycles compared to running a 13lb or 15-16lb cap.

I also recommend running the stock thermostat. It gets the oil hot so it burns off the bad stuff in the oil, making the engine last longer. It's also known to reduce engine wear in the cylinders. A cooler cylinder wears faster than a hotter one.

 

x2

So many people mistakenly fit a cooler thermostat, or no thermostat at all, & it's all loss-no gain.

Overheating isn't caused by the t/stat (unless faulty), it's purpose is to prevent the engine running too cold......which is nearly as bad for the engine as you can get.