Another 2002 Explorer Heat problem

[rmunley]

I have a 2002 Explorer XLT with the 4.0 engine. I've been having a series of heat issues so far this winter. Replaced the actuator and that's working perfectly. Once I eventually have heat I can fully control the temp. I've also replaced the water pump and the thermostat.

When I start the vehicle it takes 10 min or so before the temp gauge moves then it goes to about the middle range. Before I replaced the thermostat yesterday it would stay in the middle for about 2-3 min then drop back to cold and then moving back to the middle after 5 more minutes where it stays. With the new thermostat it still takes 10 min for the gauge to move to the middle range and it remains there without dropping.

The problem, after it warms up and the gauge is in the middle range, it still takes another 10 min before I get heat. Once the heat starts it's just fine but it shouldn't take that long to get heat.

I have noticed that during the time the engine is up to temp but I have no heat, the input pipe for the heater core is warm but the output side is cold, not even warm but cold. Once the heat starts both sides are equally hot.

Since I'm getting very good heat eventually I can't imagine the heater core is blocked. It just seems like something is keeping the hot water from actually circulating through the core until well after the engine is warm.

Again, after it's all warmed up and I have it running for 20 min or so I get perfectly good heat but as I said 20 min seems too long.

What should I be looking at next?

Thanks

 

[BigRondo]

Have you checked the heater control valve?

 

[ponkotsu]

Did you bleed the heater core? You need to disconnect the inlet/outlet from the radiator hose. Hold them high in the air and fill them with coolant.

 

[rmunley]

I had seen mention of the heater control valve but couldn't figure out exactly what it does and where it's located. Is that a part you clean or just replace?

 

[zpn_by]

rmunley, do you have the auto climate controls or the manual ones? I believe the valve Rondo is talking about is next to the passenger valve cover, along the heater line. I have the auto controls in my 02 EB and had to replace this valve last year as it had become detached from the control. If you have the auto controls, check it out and let us know. It is at least just a 5 minute fix, but cost at the dealer is about $45. I can't see the jobbers carrying it, and if so, it likely wouldn't be that much cheaper, nor would it really be worthwhile (IMHO). Your valve could be slow to actuate, which is why the supply line is hot but the return line cold.