Hello! New to the Forum. Just bought a 02 F-150 Screw XLT with 4.6L 4x4. My problem is lack of heat. I get some, enough to not freeze while driving but never enough to say I'm warm. Temps here are 20's and lower right now (-5 this morning).
So, trying to track down culprits...

---Start the engine, radiator fan always runs ( is that right or is clutch not working? With engine off, fan is stiff to turn, NOT freewheeling)
---Temp guage never gets to the half way mark
---Blower fan works and blows strongly.
---I believe blender doors work correctly ( switch from floor to panel to defrost and all air moves to the correct area)

And... if my clutch is bad, which one? reverse or regular??

My thoughts are... Radiator fans runs constantly and never lets coolant get hot enough to produce enough heat OR thermostat is too low.

What do you think?

Roger

 

Thermostat stuck open.
Low on coolant causing an air block with the heater core.
Blocked heater core.
Good luck.

 

However, the fan should not run constantly and should be easy to turn with the engine off.

 

Thanks guys!

BLUEGRASS - I thought about the Thermostat (forgot to mention)
Read about the low coolant/air bubble, I can check that too.

GLC - That is what I was wondering... now which clutch?? Rockauto shows several different ones, 2 of them are reverse clutch and the others do not specify?

Appreciate the help!!

 

http://www.4s.com/Upload/Four%20Seas...20ROTATION.PDF

 

The fan clutch may or may not be faulty but the cooling system heat has to be up to normal first, to be sure.
The fan clutch depends on radiator heat for it's function.
That heat comes from the engine with proper thermostat controlling temperature in the 195 to 200 degree range.
Then you can test it's operation with a timing light triggered by any cylinder.
Point the light at the fan blades with the engine at full operating temperature.
Wait long enough to see if the fan blade sync with the cylinder doing the trigger and make them stand still, then go out of sync as the clutch slips from temperature sensing the air coming through the radiator.
You can see from this that cooling system comes first then the fan clutch operation.
Good luck.

 

Thanks guys! I will check after this out after the next snow storm ends!

What do you guys think about using a non-contact thermometer to check temps of the radiator at the hoses?

 

If the temp gauge doesn't reach halfway, you need to replace the thermostat on general principle.

 

Ok. will replace thermostat. the temp never reaches the half way mark, maybe 1/3 but that is all....

 

Well.... after a month of looking at it and wondering I finally got off my butt and did some testing and now that winter is over.....
Hooked up a test light to a hot engine (just got home from town and left engine running) and I could see the fan change speeds. Sometimes it would appear to sync with the light and other times randomly spun. That means clutch working correctly?
Second test was with a infrared temp gun. Temp at radiator top hose was less than 130^. Sound low or about right? I did buy a new 195^ thermostat and ready to install but wanted to bounce off you guys first.

Thanks! Roger

 

Replace the thermostat.

 

I'm leaning toward a good possibility of stopped up heater core. I think 1/3 of the way is probably close to where you should be running on gauge.
Regarding fan clutch, there will typically be a notation on the shroud or somewhere nearby about direction.
I had the heater core replaced with an aftermarket core in my 01 Town Car. It doesn't get as warm now. I'm suspicious that the cheap part may be the reason.

 

Thanks guys. I will replace the thermostat tomorrow and then go from there!

 

No, it should be right in the middle.

 

Got her done today! I put in the 195^ unit and now my gauge goes to the 1/2 mark and I am getting more heat!

Thanks to everyone for all your help and patience.

Roger