HEATER WONT WORK! Checked everything but all checks out..

[broncomitch]

I have a 05 explorer with the 4.0

This vehicle was a total...the body shop did a good job fixing it but the ghetto Mexican shop the guy took it too, did a half ass,lazy, B.S. job fixing the mechanical side of this thing and it's been a year sense I bought it and I'm still fixing there crap..

Anyway, I can't figure out why the heater won't work...

I checked the flap in the dash and it's working properly, I checked the heater control valve under the hood and it's working, and I blew out the lines on heater core and it's not clogged, hot coolant is going in and out of it...

It starts to blow warm but then starts to blow cold shortly after..(the valve under the hood and dash don't change position during this)

Also, it sounds like there is a vacuum leak or something under the dash, it sounds like the CC fan running but it fallows the caricaturist's of the engine, (on the throttle, the louder it gets, ect.)
I can't seem to find anything under the dash and everything seems to be working so I'm not sure if it's related to the heater or not....?


It's really cold out lately and with the windows fogging up it's getting dangerous to drive but don't have the money to send it into my shop..

Any help is hugely appreciated!!!!!

 

[Mr Dubya]

Sorry for saying this, but did you replace the thermostat?

-Dubya

 

[broncomitch]

Have not touched it.

The motor gets up to operating temp.

Every so often the temp gauge shoots up in the red but then goes right back down where it was..coolant level is at max.

 

[rmunley]

Are you losing any coolant or showing any signs of head gasket problems? I'm not a mechanic and I don't know the reasons why it affected the heat but I had the exact same symptoms caused by a leaking head gasket. I too had looked into the heater control valve, had hot water intermittently going through the heater core, had the engine operating at normal temps, replaced the blend door actuator, in short, everything seemed OK but still had very sporadic heat that took 30 min or more to come on even after the engine was up to temp. Once the head gasket problem was fixed the heat now works perfectly.

 

[broncomitch]

I am loosing coolant, a very small amount and not sure where it's going..

Motor runs good and just replaced the spark plugs and all looked good...

Motor just passed 100k a little bit ago so would be pretty surprised if it's the head gaskets

 

[rmunley]

Are you seeing an unusual amount of white smoke from the exhaust pipe after the truck is warmed up?

 

[broncomitch]

No

 

[rmunley]

It probably wouldn't hurt to do a pressure test on your cooling system. If you're sure the system was full the coolant is either leaking out, mixing with the oil or getting burned off. Do you have discolored oil or does your overflow tank have a gas smell to it?

 

[broncomitch]

Probably not..

I'll probably add air to each cylinder to test the gaskets that way..

Oil is clean,

I didn't smell the bottle but when I blew air into the heater coil I had coolant blow out the end of the hose and some got in my mouth lol

Tasted normal and smelled the same lol

 

[broncomitch]

Even if the head gaskets are bad...I dont see why the heater wouldn't work cus of that...

 

[rmunley]

This link gives some insight. Basically he says if combustion gas leaks into the cooling system it can displace coolant. I had read on another sight that the combustion gasses and the resulting air introduced can air lock the heater core. That could be why the heat is intermittent.

Like I said in my first post, I'm not a mechanic but your symptoms and the efforts you've made so far to track down the problem are exactly the same as what I experienced.

http://www.garage-pak.com/pat-goss-washington-post/2002-wp-head-gasket-headaches.html

 

[ponkotsu]

Seems like you have air in the system. Did you properly bleed the heater cores?

 

[ponkotsu]

This link gives some insight. Basically he says if combustion gas leaks into the cooling system it can displace coolant. I had read on another sight that the combustion gasses and the resulting air introduced can air lock the heater core. That could be why the heat is intermittent.

Like I said in my first post, I'm not a mechanic but your symptoms and the efforts you've made so far to track down the problem are exactly the same as what I experienced.

http://www.garage-pak.com/pat-goss-washington-post/2002-wp-head-gasket-headaches.html

This is correct. A blown head gasket can cause the same symptoms. From the symptoms t's air in the system. The question is, how did the air get there? It's either a system leak or a head gasket. I''d take it to a full service station that has an exhaust analyzer. If there are hydrocarbons in the overflow bottle you need a new head gasket. It's a definitive test. No hydrocarbons, then flush and refill the system and see if the problem returns. If it returns then you have a leak somewhere that is sucking in air.

 

[D Hook]

Could just be a clogged radiator, too. Like mentioned above, I'd try a radiator flush and fill and maybe a flow test to see if it's flowing as it should. I had a Ford LTD that had same symptoms that turned out to be a clogged radiator.

Check/replace the cheaper parts first, if possible.

 

[KORDemon7]

It could be a bad head gasket. Sounds like it's pushing air into the cooling system and sending an air pocket into the heater core blocking coolant. The lose of coolant may be from the overflow tank. As the air builds up in the cooling system, it's pushed into the overflow tank pushing some coolant out threw the overflow hose. I would check for bubbles in the overflow tank when running.

 

[jojotheclown]

Heater core could still be bad.
3/4s of it could be blocked and still pass air, but since the water is only flowing through a small part of it, it won't transfer heat well.
Just like a partially clogged radiator doesn't cool properly.

 

[broncomitch]

Hum,

Well I checked the tank for bubles and nothing and no smell of gas..

I think I might send it to my mechanic sense I need to get everything else tested...

I have not dug into a 4.0 v6 before.. they a pain?

 

[tower]

Sorry for saying this, but did you replace the thermostat?

-Dubya

I am with Mr Dubya, it cost like $10 takes less than 30min and honestly it sounds like your problem. Heck might never have been changed so it is good maintenance anyway.

 

[Bruces expo]

Sounds like you need to do a Coolant pressure check and then a Fluid Flush .

 

[corkey]

It starts to blow warm but then starts to blow cold shortly after..(the valve under the hood and dash don't change position during this)

Also, it sounds like there is a vacuum leak or something under the dash, it sounds like the CC fan running but it fallows the caricaturist's of the engine, (on the throttle, the louder it gets, ect.)
I can't seem to find anything under the dash and everything seems to be working so I'm not sure if it's related to the heater or not....?

vacuum leak, find it and that valve under the hood will change allowing the hot coolant into the heater core,


The motor gets up to operating temp.

Every so often the temp gauge shoots up in the red but then goes right back down where it was..coolant level is at max.

that usually means the coolant is not proper, as in there is air in the system, as it heats there gets to be steam pockets, that peg the guage,,

everybody missed these key elements that could solve the problem,,