Heater question
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Joined: May 2005
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Heater question
2005 6.0 powerstroke: Ever since I have had the truck, at idle the heater blows warm/cool (luke-warm?) air through vents. When I accelerate, the heat warms up. Now that 1. I have moved to a colder (19 in the morning) area 2. the truck is well broken in (89,000 mi.) it seems to be worse. Is this just a sympptom of the efficient diesel engine? I know that some people put radiator covers (block-off) to help the engine run warmer, but would that help at idle? At freeway speeds the truck will warm, on city stop and go......not much.
Mike
Mike
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Joined: Feb 2007
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From: Rural WV
Nope...never had that problem. I've got one of the real early 6.0s (#812) and within 5 minutes of start/idle, she's blowing warm air. Within about a mile and a half, I have to dial back the thermostat setting in the truck or the heat will flat run me out of the truck. My wife who is always freezing has dialed back the heat control on the truck saying it's too hot.
If it were me, I'd start with the simple things and see what you get. Check your coolant level and make sure you're not down. I would try to block the air off (cardboard works well for the trial) and see what it does for you. You really didn't mention how long you're letting it idle/warm up. Like I said, mine seems to like about a 5 minute idle/warm up before I take off.
Let me know how it turns out!
Joe
If it were me, I'd start with the simple things and see what you get. Check your coolant level and make sure you're not down. I would try to block the air off (cardboard works well for the trial) and see what it does for you. You really didn't mention how long you're letting it idle/warm up. Like I said, mine seems to like about a 5 minute idle/warm up before I take off.
Let me know how it turns out!
Joe
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Joined: Mar 2007
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From: Claremore, OK
Broken vent flap cable? Stuck open thermostat? 
On the later we're talking about a part that uses wax to open and close...so it's possible a bad thermostat. My '04 has no trouble running me out of the cab in the city...once the engine warms up. The warming up part takes a little bit of time. For how long have you been having this problem?
On the later we're talking about a part that uses wax to open and close...so it's possible a bad thermostat. My '04 has no trouble running me out of the cab in the city...once the engine warms up. The warming up part takes a little bit of time. For how long have you been having this problem?
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I think it has been an issue since day one, it is just worse since moving to a cold area. I bet it is the thermostat. At idle (stoplight), when engine is warm, the air blows cool through the vent, as I accelerate, the air warms up. The guage slowly, steadily creeps up as the engine warms....as I think about it, it should read "cold" then "poof", (technical term), as the thermostat opens the guage should move. Weekend job for me! M
Senior User
Joined: May 2009
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From: Clearwater
This is from the workshop manual for possible causes for low and/or erratic heat
Low engine coolant level
Engine overheating
Plugged or partially plugged heater core
Temperature blend door binding/stuck
A/C electric blend door actuator
Incorrect heater control valve operation
Also, once its warmed up check the heater hoses to see if they are hot, be careful they may be very hot, if so then your flow to the heater is ok and the heater core is probably suspect
Low engine coolant level
Engine overheating
Plugged or partially plugged heater core
Temperature blend door binding/stuck
A/C electric blend door actuator
Incorrect heater control valve operation
Also, once its warmed up check the heater hoses to see if they are hot, be careful they may be very hot, if so then your flow to the heater is ok and the heater core is probably suspect
Hotshot
Joined: Jul 2005
Posts: 13,834
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From: Middle Tn.
A faulty water pump has also been linked to this problem. More so on the 03 and early 04's. But a potential contributor.
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the top hose that goes into the heater core is (very) hot. There is a vaccume controlled valve on it. no matter which dash setting I choose, it does not move. A. What does the valve control? B. Where (should) the vaccume come from? Thanks, Mike
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Hotshot
Joined: Jul 2005
Posts: 13,834
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From: Middle Tn.
That valve controls the hot water going to the heater core. Did you pull the line and see if it has vacum?
Junior User
Joined: Jul 2006
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I am very interested in the solution to this post as my 2005 PSD has begun doing the exact same thing. With the engine temp hot, the air temp from the heater vents is directly proportionate to my speed. Stopped, the air is very cool (cold?). At 30 mph, it starts to warm. At 70 mph, it's warm but not where it should be. Outside temp this morning is 34F and I had to keep the fan speed on 3 to keep the cab reasonably warm.
Hotshot
Joined: Aug 2006
Posts: 17,398
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From: Whittier, CA
If that valve is not opening, that's your problem for sure. I was checking mine out a couple weeks ago, and noticed that it opens whenever the dial is in any position except for AC, meaning defrost, floor, dash, etc. The dial for hot or cold does nothing to the coolant valve at all. It only changes air baffles.