no heat while idling.

[biggiesize]

i have a 99 sport 4.0 sohc.Just starting to get cold here in Va.I went to let the Ex warm up and after running for about 10 minutes at idle,there was barely any heat blowing.After I revved it up and got moving it warmed right up.The water level is full and it has a new thermostat.Could a bad fan clutch be causing this problem?

 

[biggiesize]

bumping for any new comers

 

[silentchris]

its normal 4.0 takes a minute to warm up

 

[waskly]

i have a 99 sport 4.0 sohc.Just starting to get cold here in Va.I went to let the Ex warm up and after running for about 10 minutes at idle,there was barely any heat blowing.After I revved it up and got moving it warmed right up.The water level is full and it has a new thermostat.Could a bad fan clutch be causing this problem?

since it uses engine temp to heat the truck and if its cold outside, till engine temp hits 180 or 190 degrees... take a bit of time.

 

[OneLever]

It helps to leave the heat running (hottest temp, second from lowest blower) while it idles. Otherwise after you get in it and turn the heat on it has to overcome the cold of the heater core and air ducts as well before you get any.

 

[my98nnj]

Does the engine get up to operating temp (temp gauge) while idling?
If so, and your not getting any heat, then you may have a blockage in the heater circuit. Check the heater core flow control valve, make sure it's operating correctly.
Also check the heater core itself for blockage by flushing it with a hose.
If the temp guage moves away from C, you should get heat, idling or driving.

 

[12beemer34]

Check that you are running a winter thermostat. It will delay opening up until the engine reaches a higher temperature.

Even though its a new thermostat, it may be failed open. I had a brand new thermostat fail open a week after I put it in.

As others have posted, check for blockage in heater core.

 

[2TimingTom]

Does the fan actually work on whatever setting it was on? I've noticed that on the low setting on mine, the airflow is pretty minimal. As you're driving, the outside air will create extra airflow through the vents- basically making it feel like the fan is turned on higher than it actually is. And at idle, an engine will take longer to warm up than an engine that's driving.