No Heat - Diesel Forum

RLSVT · 12-05-2005, 09:25 PM

Anybody have this problem, It's an 04 6.0 when I accelerate it will blow hot air and when at idle it blows cold? any way it's going to the dealer in the morning
Ross

Nubbs · 12-05-2005, 11:57 PM

Not me. Let us know how it turns out. You've definitely got an interesting issue.

GrampyJim · 12-06-2005, 12:40 AM

Last one I had like that needed a heater core to fix it. A late 03 with only 32,000kms on it and seemingly good flow through the old one using a garden hose, I was nothing less than surprised. Something we forget.... head pressure in a towns water system is much higher than that produced by the water pump on our engines.

Here are the symptoms I encountered.... good heat while at speed..... heater output cooled fairly quickly at idle.... 30 seconds or so would put heater output close to outside temp (between freezing and 0F at the time I was diagnosing).... temperature gauge in the cluster did not change when the heater cooled or warmed..... ECT reading on the WDS did not change when the heater warmed or cooled. Hotline turned into lukewarm line on this concern and had me chasing unicorns....

HTH

Davemcfarland · 12-06-2005, 09:01 AM

I have the extact same issue.. I just discovered it this morning.. NO IDEA..

suprstructure · 12-06-2005, 09:34 AM

When that happened to my truck my dealer asked if the overflow was at the min level and it wasnt so they told me to fill it, watch it and see, 1 year later and 1 more fill this fall and I have had steady heat but never the heat that For% trucks always produce.(nice and toasty with minimal fan!)

RLSVT · 12-06-2005, 06:46 PM

I have to bring it in this thurday. as soon as I find out what is wrong i'll repost
thanks Ross

RLSVT · 12-10-2005, 02:44 PM

got the truck back form the dealer. It tured out to be a bad radiator hose. the reason I never noticed is that I have a gravel driveway [img]/ubbthreads/images/graemlins/shrug.gif[/img] The anti freeze was not full enough to go threw the heater core. they replaced the hose and topped it of.

Ross

lubeowner · 12-21-2005, 08:00 AM

I'm having a heater problems. I drive down the road and the heat will just go from hot then cool to cold and then then back to hot again. It does it at very randon times. Sometimes going up hill, sometimes going down hill, at one stop light but not at others, and so forth. Just driving down the road the engine temp stays right in the normal range with no flucuation.

What I've tried. Flush the heater core and every line that i can find. removed the heater control valve that is located by the oil filler neck, added a second layer of cardboard to the front of the radiatior. Changed the thermostat.

I am now out of ideas. Any new things to try would be helpful.

CalWaterboy · 12-21-2005, 08:20 AM

[ QUOTE ]
I'm having a heater problems. I drive down the road and the heat will just go from hot then cool to cold and then then back to hot again. It does it at very randon times. Sometimes going up hill, sometimes going down hill, at one stop light but not at others, and so forth. Just driving down the road the engine temp stays right in the normal range with no flucuation.

What I've tried. Flush the heater core and every line that i can find. removed the heater control valve that is located by the oil filler neck, added a second layer of cardboard to the front of the radiatior. Changed the thermostat.

I am now out of ideas. Any new things to try would be helpful.

[/ QUOTE ]

Assuming your coolant level's good and you're not adding coolant, there is an on/off valve in the coolant line to the heater. If that's the heater control valve you changed, I'd look for an electrical problem. You'll notice on Max AC that there's no heat....that's the valve operating.

Hey, anyone know if it's normally open? Normally closed?

I'd like to have heat in Max AC....it's nothing more than recirc mode. If that can be fixed by the wire falling off, great.

The Japanese do it better - Ford's recirc control is awkward; crude. So's their cruise control. Check Honda & Toyota.

overfly · 12-21-2005, 08:21 AM

Head gasket? [img]/ubbthreads/images/graemlins/shrug.gif[/img]

lubeowner · 12-21-2005, 10:40 AM

my coolant level is full. I have been filling it. Now that it is cold I fill it at about 1 gallon per month. Mine is a puker. I'm scared a head gasket is the problem. Would bad head gaskets cause this, maybe air pockets. I now that when head gaskets cause low coolant then no heat is an issue. My coolant isn't low???

I pulled the coolant return line off at the overflow bottle, from the egr cooler and I get a lot of air bubbles, maybe exhaust gases in this line. Maybe holes in the egr cooler causing puking and no heat?????

Jeremy

CalWaterboy · 12-21-2005, 11:36 AM

[ QUOTE ]
my coolant level is full. I have been filling it. Now that it is cold I fill it at about 1 gallon per month. Mine is a puker. I'm scared a head gasket is the problem. Would bad head gaskets cause this, maybe air pockets. I now that when head gaskets cause low coolant then no heat is an issue. My coolant isn't low???

I pulled the coolant return line off at the overflow bottle, from the egr cooler and I get a lot of air bubbles, maybe exhaust gases in this line. Maybe holes in the egr cooler causing puking and no heat?????

[/ QUOTE ]

Try keeping coolant @ minimum level - may puke no more. Isn't there a chemical check for exhaust in coolant?

CalWaterboy · 12-21-2005, 11:41 AM

[ QUOTE ]
I'm having a heater problems. I drive down the road and the heat will just go from hot then cool to cold and then then back to hot again. It does it at very randon times. Sometimes going up hill, sometimes going down hill, at one stop light but not at others, and so forth. Just driving down the road the engine temp stays right in the normal range with no flucuation.

What I've tried. Flush the heater core and every line that i can find. removed the heater control valve that is located by the oil filler neck, added a second layer of cardboard to the front of the radiatior. Changed the thermostat.

I am now out of ideas. Any new things to try would be helpful.

[/ QUOTE ]

No sooner did I mention it than <font color="blue">I SAW THIS....</font>

Evidently a vac hose activation. I'm gonna fix mine so I get heat in Max AC. May cure yours.

lubeowner · 12-21-2005, 12:25 PM

I would like to start by saying last year I was in -20 degree temps and did not need to cover my radiator to get heat out of my truck and it didn't have this problem.

A heating system is very simple right? The water pump pumps coolant throught the heater core, a fan blow heat out of the vents, the coolant retuns to the overflow bottle. This will happen even if the thermostat is in any position.

Is there only one valve that control the coolant flow to the heater core, the one by the oil filler neck? I removed this possible restriction.

There are also flaps inside the heater box to control if the air flow into the truck through heater core or not??? If I turn the heater control know I can hear a sound difference in the air flow sound. It does this even when the heater is blowing cold air.

As long as the coolant is full enough shouldn't the water pump pump even if the head gaskets are bad??

Are there more valves on the truck other than the one I removed that control coolant flow through heater core?

overfly · 12-21-2005, 05:26 PM

A bad head gasket can cause intermittent heat loss by causing an airpocket that works it's way through the cooling system. Being a puker makes it sound all the more likely that it could be a bad head gasket causing the problem.