no heat, 02 4.6l explorer

[02 Explorer V8]

I'm get no heat in the cab from both front or rear heater, I have replaced the thermostat, water pump, and flushed the cooling system. The line into the heat core hot to the touch, the other side slightly cooler but still hot to the touch.

Any ideas would be helpful.

 

[TCP Sport]

Well you've eliminated most of the common causes of a no heat issue. But it could be some other things.

First off open the cap on the radiator after the truck cools off and double check your coolant level with the truck running and let the thermostat open. Fill if needed.

What's the temp gauge reading?
Will it get even slightly warm at all if you start driving?
Have you heard any hissing sounds coming from under the dash?
Is the vent selector switching the air to blow out of all the different outlets?

It could be a vacuum leak.

 

[02 Explorer V8]

When I remove the rad cap, it gives off some presure and the coolant level looks good.

I have looked at the blend door actuator and seems to be working fine, controls seem to work fine changes from hot to cold and the air distrabution seems to work fine changes at every setting.

Temp gauge on dash sit's dead center.

It does get slightly warm when driving, thouht I had a weak water pump, that is why I changed it.

I don't seem to hear any hissing, under the dash so I don't think I have a air leak.

I don't see anything on a cab air filter, do I have one maybe pluged?

Thanks

 

[ponkotsu]

Seems odd that both would plug up at the same time, but based on the symptoms that seems like what's happened. I'd suggest you flush them out with CLR. You have to disconnect the hoses near the front of th engine. Blow them out with compressed air first. Then hold them as high as possible and fill the hose with CLR. Let it sit in there about 20 minutes. Then flush out with a garden hose. You need to fill the heater cores with coolant before reconnecting them. Hold them high in the air and fill with a funnel then reconnect. When flushing it's best to use a clamp and pinch off one core at a time to be sure you are directing the flow to the appropriate core. There is a specific procedure for this in the Ford manual. I don't know what the procedure is on the 02 and your engine.

 

[rocco123]

Maybe by-pass the heat control valve (at heater hoses) by taking it out and using a 1/2 inch section of copper pipe. At least it will eliminate it as a cause. I always carry a section of 1/2 in and clamps in case a line breaks.

 

[TCP Sport]

Seems odd that both would plug up at the same time, but based on the symptoms that seems like what's happened. I'd suggest you flush them out with CLR. You have to disconnect the hoses near the front of th engine. Blow them out with compressed air first. Then hold them as high as possible and fill the hose with CLR. Let it sit in there about 20 minutes. Then flush out with a garden hose. You need to fill the heater cores with coolant before reconnecting them. Hold them high in the air and fill with a funnel then reconnect. When flushing it's best to use a clamp and pinch off one core at a time to be sure you are directing the flow to the appropriate core. There is a specific procedure for this in the Ford manual. I don't know what the procedure is on the 02 and your engine.

Agreed. Based on what you've relayed back here I'd say this is you're best bet as well. Still seems strange. But I guess it's possible.

I had a heating issue where it would blow cool at idle. It wasn't really bothering me until one day I noticed the temp gauge was getting up there. Turned out I was just low on coolant.

Hope you get it fixed. Especially if you're on the central East coast. Nine degrees here.

 

[02 Explorer V8]

Thanks everyone, I will try to flush again this weekend, and do a little more inspection since it's been to cold to try anything lately.

Last week has been from -40 to -50 celsius every day, hope to figure this out soon.

Thanks

 

[ponkotsu]

Thanks everyone, I will try to flush again this weekend, and do a little more inspection since it's been to cold to try anything lately.

Last week has been from -40 to -50 celsius every day, hope to figure this out soon.

Thanks

Oh, maybe that's the problem. It's too cold up der! The heating system can only warm up the air by some amount. 40C? So if it's -40C outside you are still going to blow 0C air. I don't know the exact numbers but there is a limit.

 

[TCP Sport]

Thanks everyone, I will try to flush again this weekend, and do a little more inspection since it's been to cold to try anything lately.

Last week has been from -40 to -50 celsius every day, hope to figure this out soon.

Thanks

WHOAH... I didn't know you were in those temps. Thermostat stuck? Can't overheat cause it's so cold?

I have no experience dealing with vehicles in sub zeros.

It's an improbable theory but possible I guess.

 

[02 Explorer V8]

Hello everyone, flushed the heater core again not much change on the front heater assy. But I have noticed that the center console heater is pumping out good heat, but still just warm air out of the front heater, so going to have to investigate some more.

Figured out the rear heater problem, the blend door is damaged were the motor joins to the door, so I wasn't getting any clicking noise because the motor was moving freely in the blend door. Has anyone changed the rear blend door or do I have to change the complete assy?

Thanks

 

[TCP Sport]

Prop that sucker open for a temp fix. I figured it was something in the dash.