My problem is that the air is not very warm, there is plenty of air flow, I also cleaned the ducts when I replaced the heater core. And yes they were packed full of leaves. Once again I replaced the following:

New Heater Core.
New Thermostat.
New Anti-Freeze with FW-16.
Water pump was recently replaced by the previous owner.
Radiator cap is original but it still holds the 13psi and does not leak.

The engine just does not want to heat up. I plug it in overnight, then warm it up ten minutes, and then dive about 10 miles in stop and go traffic. By the time I reach the destination the engine is just getting slightly warm heat.

 

Will it build temperature when you drive it on the open road.You may have to go to a hotter thermostat ( 190 ) or get a winter front. It sounds like your thermostat not working right,did you go to Ford to buy your thermostat.I use to buy my thermostats at O'Rielly's and they would run either too cold or too hot the brand name is Stant. I went to Ford and haven't had any trouble since.

 

I got a motorcraft thermostat about 3000 miles ago and did not notice any difference. I also have the radiator 60% blocked off with cardboard and it still does not get up to (192) operating temp. If I travel on the interstate 65-70 mph it will actually cool down. Gauge will read 1/4 of the way. Where can I get a hotter thermostat, ford only offers a (192).

 

Hi, my truck did the same thing cooled off when I went down the road at speed about three weeks later the fan clutch locked up it is hard to tell except for the loss of power once in awhile you can hear the roar but not to often I guess because of all the insulation between you and the engine my fan would turn but was really tough it made a world of difference when I changed it.
John

 

My cooling fan roars for about 10 seconds when I step on the gas only when the engine is freezing cold. But when I start driving it does not roar. When engine is "WARM" it turns very easy, but when very cold it turns very hard. Is this normal?

I also held the fan while someone started it and I could hold it just fine, when it was warm of course. I did not try it cold.

During the summer the only time it roars is when I am traveling 70 mph and get off a ramp. As soon as I step on the gas there is no power and it sound like it is going to take wings and fly. My engine is at the upper normal scale when this happens. Also, even though I replaced the thermostat, could it still be defective?

 

Hi, it is possible for the thermostadt to be bad try taking it out and put it in a pan of water on the stove watch to see when it opens and then let it cool down and see if it shuts all the way. Also keep your ears open for that fan because mine didn't make much noise at all and then one day it locked up and there was a considerable amount of power loss when I changed it it felt like I added 20 H.P. the truck is pretty fast for 7000 lbs.
hope you get this thing figured out I know what a headache these things can be, but in a ten mile run my heater will cook you if you don't turn it down. Good Luck. John

 

Take the thermostat out and put it in a pan of water on the stove,get a candy thermometer and see what the temp is when it opens.Beyond that your clutch fan could very well be at fault,with a 192 thermostat you should have plenty of heat.

 

When I find the time I am going to do some more checking, In my opinion I think it is a defective thermostat because the radiator is warm in the morning after I plug it in. If the thermostat is closed it should not allow the heater to warm the radiator. Am I right? I may also take the fan off and drive it and see what happens. I think I have it narrowed down to 2 things thanks to you guys, either the fan or thermostat. Thanks for the input!

 

I wouldn't think a block heater could get hot enough to open a thermostat. You might have something holding the thermostat open or it might not be closing after it cools off.

 

I want to thank you guys again for all the help. I took the thermostat out once again and sure enough the spring was broken. I called ford and they said thermostats were not returnable. I told them it was defective from the day I got it. It made no difference. So I cleaned up my old original thermostat with some CLR and some baking soda. I then had my friend return it with the receipt, and told them that was not the problem, and with no questions they give him the money back. I called them back later that day and told them what I did, and that I will never do business with them ever again, and they got mad at me. So I took the money and went to another ford dealer and bought a new thermostat and checked it when I was there. I put it in the truck and sure enough, I had heat within 6 minutes and full heat within about 15-20 minutes. With all of the messing around with ford and the time it took me to put it in, it took me 5 hours. Once again, I want to thank all you guys for all the time spent helping me solve the problem!

 

Good for you on the thermostat some of these parts guys can be real JERKS!!!!

 

About how much time does it take to R+R a thermostat

 

All good suggestions. It sounds like a improper operating T Stat to Me.

One other thing to check is the Heater Door. There is a tendency for the seal to rot, and the hinge to break. If either happens, it lets cold air passed the door. Effecting heat output. It also hinders AC temps considerably.

My 85 Reg Cab will burn You outta the cab even at below zero temps. Without covering any of the radiator. If the system is up to snuff, You shouldn't need to cover the front.

 

Well the 1200 watt block heater will put out enough heat to open the T-Stat. If it's allowed to run long enough. Anything over 3-4 Hrs and You can feel the upper hose is HOT! And pressurized.

IE: the T-Stat has allowed hot coolant to flow passed it.

 

fonefiddy--This thread is 10 yrs,old lol.