2001 Explorer Heat issue

[Joeetogo90]

I know there are several posts about heat issues with the explorers, but I never seem to find a definite answer. I know each issue is different so I have been brainstorming ideas. I have a 2001 Explorer XLT with 127,000 miles and the heat seemed to be working okay when the temp was in the 20's here in Wisconsin but now that it's below freezing I don't get hot heat no matter how long the truck has been on. The temp gauge never rises past the line by the C mark. Usually it rises up to that line then when I start to accelerate then it drops back to C. It blows kind of blows lukewarm heat out and when I'm on the highway accelerating it seems to blow warmer heat but once I'm back to city speeds, it goes away. I touched the two hoses that come out of the firewall on top of the engine on the passenger side and they are not hot at all, just barely warm. I was thinking maybe I need to swap out the thermostat? I saw posts about the blend door actuator and mine seems to be working fine. The AC doesn't work but when I switch the temp control from hot to cold it seems to be pulling the cold air in from outside, so I assume all is well there. The only issue I notice randomly is when I go to shut the heater off, sometimes it runs for an additional 5 seconds or so then shuts off. I don't really have much mechanical experience but I've been managing to get by so far lol!

 

[XLTrunner]

It's the classic problem experienced in this part of the country in the winter and is probably due to a stuck thermostat or low coolant. First thing you need to do is check the coolant level. Even if your reservoir has fluid, you should remove the radiator cap and check the level inside the radiator (engine cool, of course) just to be sure. If that's fine, then I'd focus on replacing the thermostat.

 

[Joeetogo90]

It's the classic problem experienced in this part of the country in the winter and is probably due to a stuck thermostat or low coolant. First thing you need to do is check the coolant level. Even if your reservoir has fluid, you should remove the radiator cap and check the level inside the radiator (engine cool, of course) just to be sure. If that's fine, then I'd focus on replacing the thermostat.

I went out at lunch and looked at the coolant level and it's way past the cold fill line on the container. I never thought about checking the radiator cap....If I don't see coolant when the cap is removed, does that mean I need to add some? When I went to pick lunch up I noticed that when the truck starts the gauge is below the C area, then once I'm driving around that's where it climbs up to the line after C but then drops.

 

[Joeetogo90]

I went out at lunch and looked at the coolant level and it's way past the cold fill line on the container. I never thought about checking the radiator cap....If I don't see coolant when the cap is removed, does that mean I need to add some? When I went to pick lunch up I noticed that when the truck starts the gauge is below the C area, then once I'm driving around that's where it climbs up to the line after C but then drops.

Oh I forgot not mention that even when it's decent weather here, the temp gauge never goes past C much at all, so I wasn't sure if something was faulty with the way it reads temps.

 

[Joeetogo90]

Both the coolant container and Radiator Cap are good to go.

 

[XLTrunner]

Okay on the coolant.

If not for the fact that you aren't getting good heat, I wouldn't be too concerned with the Temp gauge not reading correctly. That could just be a bad Sending unit or the gauge itself. However, since you're getting poor heat, I'd still be focusing on a stuck thermostat. Your heat output should be strong while driving it once the engine is fully warmed up...and, the gauge should read near the middle...even in this sub-zero cold we've been having. If the thermostat is stuck open, it's allowing full flow of coolant thru the radiator without restriction...and, not allowing it to heat up to normal operating temperature on these extremely cold days we've been having lately. Thus, poor (or, no) heat inside the truck. On a milder day (say, +25F or above), it's going to feel like you have a little heat...but, it's still probably less than what you would normally be getting. Good news is that it appears you don't have a coolant leak...so, that eliminates some more serious issues and the need to replace your t-stat housing. Get a name brand thermostat, new gasket (usually comes with a new t-stat) and swap it out. Personally, I always test my new t-stats on the stove with a pan of boiling water and a thermometer as it's not unheard of for new ones to be defective right out of the box. Good luck and report back.

 

[Joeetogo90]

Okay on the coolant.

If not for the fact that you aren't getting good heat, I wouldn't be too concerned with the Temp gauge not reading correctly. That could just be a bad Sending unit or the gauge itself. However, since you're getting poor heat, I'd still be focusing on a stuck thermostat. Your heat output should be strong while driving it once the engine is fully warmed up...and, the gauge should read near the middle...even in this sub-zero cold we've been having. If the thermostat is stuck open, it's allowing full flow of coolant thru the radiator without restriction...and, not allowing it to heat up to normal operating temperature on these extremely cold days we've been having lately. Thus, poor (or, no) heat inside the truck. On a milder day (say, +25F or above), it's going to feel like you have a little heat...but, it's still probably less than what you would normally be getting. Good news is that it appears you don't have a coolant leak...so, that eliminates some more serious issues and the need to replace your t-stat housing. Get a name brand thermostat, new gasket (usually comes with a new t-stat) and swap it out. Personally, I always test my new t-stats on the stove with a pan of boiling water and a thermometer as it's not unheard of for new ones to be defective right out of the box. Good luck and report back.

I put the new thermostat in and the heat works great and my temp gauge is normal but now I'm leaking coolant somewhere? Never had any leaks prior to this.

 

[koda2000]

What engine do you have? If it's the 4.0L SOHC V6, the plastic thermostat housings are prone to cracking. Common problem.

 

[Joeetogo90]

What engine do you have? If it's the 4.0L SOHC V6, the plastic thermostat housings are prone to cracking. Common problem.

Yeah that's the engine I have. What's weird is that the fluid leaking looks orange but my coolant is green. I drove it home from work which is a 40min drive and once I got closer to home the heat turned cold for a few minutes then went back to hot. The engine started smoking solid white smoke and i didn't even realize it until I parked in the driveway lol.

 

[koda2000]

Yeah that's the engine I have. What's weird is that the fluid leaking looks orange but my coolant is green. I drove it home from work which is a 40min drive and once I got closer to home the heat turned cold for a few minutes then went back to hot. The engine started smoking solid white smoke and i didn't even realize it until I parked in the driveway lol.

Oooo, that's not good. Solid white smoke usually means a blown head gasket. Check your engine oil to see if it looks like chocolate milk. Also check your coolant to see if if has oil in it. The loosing heat and then having it come back is a sign of a low coolant level. Is it possible the engine overheated? If the coolant level was low the TEMP gauge sender wouldn't register the fact that you were overheating.

 

[Joeetogo90]

Oooo, that's not good. Solid white smoke usually means a blown head gasket. Check your engine oil to see if it looks like chocolate milk. Also check your coolant to see if if has oil in it. The loosing heat and then having it come back is a sign of a low coolant level. Is it possible the engine overheated? If the coolant level was low the TEMP gauge sender wouldn't register the fact that you were overheating.

I didn't check my oil yet but I noticed that the coolant is slowly leaking in between the thermostat housing lid and where it connects to. I tried repositioning it but I keep having issues where one of the 3 screws that hold the lid on goes in crooked so I don't think its sealing properly. The radiator cap and coolant container were almost empty even though they were full earlier. The smoke is coming from behind the. Thermostat holder.

 

[XLTrunner]

Don't think your problem is a blown head gasket. Everything was fine before you changed out the t-stat, so start there. Remember, a coolant leak on a hot engine in cold temps greatly enhances the amount of smoke or steam over what you'd see on a warm day. I think you're on the right track with the t-stat cover not being seated correctly. It can be hard to access with the upper intake manifold in the way. Take it off and try again. Just don't go all gorilla on it when torquing it down. As Koda mentioned, they will crack under too much torque. And, hopefully, you haven't stripped the threads on that stubborn screw hole. If you just can't seem to get it sealed, you may need to remove the upper intake manifold...and, that requires considerably more work and new gaskets for it when reinstalling. If it comes to that, don't hesitate to ask questions on here. Many of us have gone thru this procedure and can offer some insight and tips on how to tackle that job.

 

[koda2000]

@Joeetogo90 I was assuming you were saying the "solid white smoke" was coming out your exhaust pipe (that's why I was thinking blown head gasket). If the smoke/steam was coming from near the T-stat housing and you've buggered the bolt thread(s), you may need to replace the housing. I don't think you need to remove the intake manifold to do this, but while I've changed the T-stat on my '01 SOHC and replaced the water pump on my '97 SOHC I've never had to replace the T-stat housing. The bolts screw into brass inserts in the plastic and once the inserts start to turn in the plastic they leak.

BTW: If you do end up replacing the T-stat housing you might want to consider getting the updated one with the push-in coolant sender and sensor (rather than the screw in kind) because the screw-in kind tend to eventually leak.

 

[Joeetogo90]

Thanks everyone for the help. I will go and look at it again if it stops raining here. Do you know if the o ring is supposed to sit on top of the thermostat freely? When I installed it on top of the thermostat I tucked it down on the top/almost side of it. Was that not right? It looked weird just sitting where it was before pushing it down a little.

 

[koda2000]

Thanks everyone for the help. I will go and look at it again if it stops raining here. Do you know if the o ring is supposed to sit on top of the thermostat freely? When I installed it on top of the thermostat I tucked it down on the top/almost side of it. Was that not right? It looked weird just sitting where it was before pushing it down a little.

Sorry, I don't recall about the O-ring. I was thinking it was split and fit around the edge of the metal t-stat, but I could be wrong about that.

Edit: As I think about this, I think the O-ring seals the upper and lower housings together and really has nothing to do with the t-stat. The bolts should only be tightened to 89 inch pounds.

 

[XLTrunner]

Edit: As I think about this, I think the O-ring seals the upper and lower housings together and really has nothing to do with the t-stat. The bolts should only be tightened to 89 inch pounds.[/QUOTE]

I believe this is correct, too. I vaguely remember thinking it was weird the t-stat didn't use a gasket or O-ring until it was obvious the O-ring that sealed the two t-stat housings together is what kept it from leaking.

Remember...as Koda stated, it's 89 INCH POUNDS not Foot Pounds that is so commonly used as a reference when tightening bolts.

 

[Joeetogo90]

Well ink what happened but I got the thermostat housing repositioned a littler better...hooked everything back up and now I can't get it to stay on. It starts then immediately shuts off followed by the check engine then check gauge light. The only thing I did differently this time was disconnected the ground? Or positive cable on top of the alternator since it was in the way. I give up lol

 

[Joeetogo90]

Got it started...the metal cable on the throttle must have been positioned weird. I tried everything then pulled back on it to give it some slack and it started right up. Still leaking coolant though. The thermostat housing wont sit flush with the lower half no matter what I do.

 

[koda2000]

Got it started...the metal cable on the throttle must have been positioned weird. I tried everything then pulled back on it to give it some slack and it started right up. Still leaking coolant though. The thermostat housing wont sit flush with the lower half no matter what I do.

As I recall, with a new O-ring in place, the top doesn't sit completely flush. The bolts tighten just enough to provide a seal when torqued properly. This may leave a bit of a gap between the upper and lower housing. If you try to over-tighten the bolts it ill crack the housing or pull out the brass inserts. At this point you're probably looking at replacing the t-stat housing. Pretty common issue. I suggest you do not purchase a Dorman replacement. Most Dorman stuff is crap. I only use Dorman when there's no alternative. The newer design Ford housing uses the coolant sender and sensor that push in a seal with O-rings (they're held in place with with a metal clip). I would seriously consider upgrading to this style housing.

 

[XLTrunner]

That's correct...the O-ring prevents the two halves of the t-stat housing from bolting up flush with each other. Are you drawing down the t-stat housing evenly onto the O-ring by alternating the tightening of the three bolts? Are you getting the correct O-ring? Before I gave up and took on the more involved job of replacing the entire housing, I'd double-check my work and maybe even try a new O-ring (they're cheap).