Heater Cold at Idle?

[jpxj94]

My Heater is cold at idle but as soon as you give it a little throttle it warms right up. It does this even when the truck is at full operating temp. Any suggestions to check?
Early 99 f250 7.3

 

[JLDickmon]

used to see a lot of Taurus/Sables with that condition when the heater core got partially plugged...

tell us your mods... a mod to the cooling system my have something to do with it..

 

[jpxj94]

No cooling mods. Just bully dog chip, diy intake, 4"downpipe 5" straight exhaust, 12'" lift 38's, and 05 front conversion.

 

[DaveBen]

Maybe a partially stuck thermostat? Partially open that is.

Dave

 

[jpxj94]

Nope just put a new Therostat in last week, it did the same with the old one.

 

[bushpilot]

could you have a heater valve issue ? is it open all the way ? or not
flowing til you blip the throttle ? which might make me wonder if the
water pump is flowing fully.

hey your 'round the corner from me...give it a day you wont need
heat

 

[arrowstrap]

this might sound silly, but check your radiator fluid level.

 

[jpxj94]

Fluid level is good, Water pump was replaced 2 months ago, I havent checked the heater valve yet,

hey your 'round the corner from me...give it a day you wont need
heat

Yeah I live in Augusta Pines off of Kuykendahl and huffsmith. Not to far

 

[Crumm]

Just thinking out-loud but does anyone know what controls the temp valve? If the valve is run by vacuum then the Vacuum pump could be getting weak and causing the valve to close at low rpm?

 

[CSIPSD]

Vacuum pump on the SD is electric, so idle speed would not effect it other then if the alt. is going bad...