Explorer overheats after fan comes on and no heat in the cabin.

[Csylvia02]

My 2010 Ford Explorer experienced a radiator leak between the radiator and the plastic tank on the top, so I replaced that, we were still not experiencing any heat while driving it. I watched a couple of videos on how to "burp" the system, to no avail.

Next I replaced the thermostat, and "burped" it again, still no heat, so I drained and flushed the system yet again and still no heat. What else is there to check? I have the Haynes manual and did the flush and fill the way the book said and still have no heat I am about to lose my mind.

The blend doors sound like they are opening. They are not clicking like they are broken.

The heater is on full the entire time, I have not rotated the dial since I started this.

I unplugged one of the hoses on the heater core and blew into it, the hose was bone dry and I blew into the end of the hose and fluid came out of the cabin side metal tube. I also plugged a water hose into the tube and ran water through it to make sure it wasn't clogged, it is not. Front and rear heater cores.

Here is everything thing I have done from the start:
Replaced Radiator.
Replaced Thermostat.
Drain and flush and re-service.
Checked for leaks out of the water pump weep hole (none) and operation of pump, the upper hose gets hot and I feel water go through it when the thermostat opens.
Check the radiator cap for pressure, it opens at 20psi and hold between 17-19psi. Replaced radiator cap anyway.
Removed supply hose and ran coolant to help purge trapped air.
Ran water through the supply and return hoses on the heater core. On the front and rear.
Check operation of heater control valve, works.
Turned vehicle on while watching the exhaust pipe, a small amount of water on initial start up in the morning but no smoke.

Problems still occurring:
Drive vehicle it over heats but returns to normal at idle I also get the coolant light that extinguishes when the car returns to idle. Even though it says its overheating the car has not pushed coolant into the expansion tank.
The car will not take any more coolant, and only overheats after the fan comes on. And still no heat.

My background is no car experience, I am a helicopter mechanic and if this was an AH64 I would be done by now. SO please take it easy on a rookie shade tree mechanic.

Should add, 4.0L engine, no oil in water after flush and the engine oil looks like engine oil not milky. Next step was a water pump someone please talk me out of that.

 

[Explorer75]

Enve thou this web page says it´s for Honda it helped me with a Toyota Tacoma that was overheating a couple of years ago.

Look for "Overheats when driving at speed, or on repeated heavy acceleration".

I hope this helps

http://www.tegger.com/hondafaq/overheating/index.html

 

[Csylvia02]

Enve thou this web page says it´s for Honda it helped me with a Toyota Tacoma that was overheating a couple of years ago.

Look for "Overheats when driving at speed, or on repeated heavy acceleration".

I hope this helps

http://www.tegger.com/hondafaq/overheating/index.html

Thanks, it seems most of the troubleshooting it is giving me is most of the stuff I have already done

 

[Flag Gibby]

How much coolant will the vehicle take? Also, when you replaced the cracked upper thermostat housing did you make sure that the coolant takeoff for the heater on it was not plugged/capped in shipping for some reason. A bone dry heater core indicates that you are getting no coolant flow from the upper thermostat housing.

Thought of this after posting:
The only thing that I can think of, and I am sure that you didn't do it considering your background, but installing the thermostat upside down could cause the system to be starved of coolant when driving due to the water pump forcing the thermostat closed. So, something else to check just to be sure.

 

[Csylvia02]

The manual says it should take 13.2L but it hasnt taken nearly all of that. I didn't replace the housing, it isn't cracked or leaking, just the tstat, and the tstat is installed correctly, looking at it they seem kinda "Joe" proof. Like they only go in one way, and you really cannot mess it up.
Fixing to take the tstat out and put it in boiling water, to see if it opens.

Thanks for your help though. I have been at this for over a week now. Would a weak water pump prevent flow to the heater core?

 

[Rickademus]

Hey Csylvia02 im feelin your stress... Im currently a UH60 mechanic but im more of a automotive mechanic by trade..
One way to check the system is to pump the lower hoses by hand before you start the engine with the cap off the expansion tank and keep filling the system hopfully this should remove any air lock.
Once you are satisfied you cant fill the cooling system any more then start the engine and feel the hoses as it warms up .
If you suspect there is still a problem remove the return line hose to the expansion tank and there should be coollant flowing from the hose back to the tank.
If you are not getting any flow back its normally water pump related on some other makes of pumps the impeller can slip on the shaft causing an over heating situation. Also you want to feel the hoses by hand including the heater hoses going to the bulkhead (firewall).
Ive turned wrenches on 2 AH64D i was worked section 1-4 and 7-8 (exhaust system ) back in 2012.
Hope this helps a bit Rickademus

 

[Csylvia02]

Thanks Ricademus, here is my question; If the hot water from the upper hose gets hot because it is returning from the engine and running down through the radiator to cool off would the lower hose really be hot?
It is always cool to the touch but he upper hose it is hot.

My next question is about the expansion tank, my expansion tank is seperate from everything and it has only one line going to the neck of the radiator. So when the cap opens up under pressure it sends coolant to the expansion tank or into the radiator as needed.

Also both of my heater hoses going to the heater core are not hot at the fire wall it is hot coming off of the tstat housing into the metal tube around the alternator and back into rubber hoses it gets cool again.

Right now I am working tail and engines. Where are you at? I am at Campbell.

 

[Rickademus]

Im at Clay Kerserne Germany.
Do you think you may of left a blanking plug or transporting cap on the radiator because something is blocked and your cooling system is not circulating properly. The only problem with the truck was that it had a coolant leak from the radiator and it was working ok before. You need to be 100% sure.. Im not trying to make you look silly here OK...
If the Radiator is ok i would pull the hose to the neck of the rad and see if it is pumping out any coolant . I cant see your engine im just helping from experience
Rick

 

[Csylvia02]

No I do have that down to a science, it didn't come with plugs in it, just plastic sheets covering the holes. The hose on the top is pumping fluid to the top, I noticed this when I tried to vent the air this morning a guy suggested putting a flat tip screw driver between the neck and the hose to give the air a place to get out.

 

[Csylvia02]

And yes, the car was running without issues before. Noticed the heat went out, checked under the hood, radiator was leaking. Ordered a replacement and then went on as described above.

 

[Rickademus]

It sounds like you have an air lock then. On some vehicles like BMW and French cars they have bleed screws made out of plastic or metal you find them on the top of the radiator thermostat housing or sometimes on the heater hoses these help with the bleed process. I haven't seen them on my 05 explorer . So I suggest you extend the gravity water level using a old plastic soda bottle cut bottom off and use as a funnel. fill the funnel higher than the top of the engine and pump the hoses by squeezing and watch the water level rise and fall keep doing this with engine off. If necessary remove one top hoses fill from there using another funnel just force the coolant in the engine somehow your not going to hurt anything. Sometimes you get sediment build up in the smaller hoses 12mm 3/8 7/16 size that can cause problems usually on old neglected cars though.

 

[pzy3339]

If you start the engine with the radiator cap off and the radiator full you should see the coolant start flowing once the engine reaches 195*F, which is the temperature the thermostat is designed to open at. Do not use a 180*F thermostat.

The fan will kick on soon after that if temps continue to rise. I believe around 210*F.

If you see no flow the pump may be dead. Or there is a blockage of some kind.

The inlet hose should be hotter than the outlet hose on the radiator. The outlet hose should not be cold after the first time the thermostat opens up. It will be hot, just not as hot.

Also, the air blowing off the fan should be hot. If the fan is on blowing cold air there is insufficient(or zero) coolant flow. This is how I diagnosed my thermostat going bad.

The air pocket thing is interesting, I did not have that problem when I refilled mine. I did what Rickademus said actually. Used a funnel and squeezed the tubes, then started it up with the cap still off and kept the funnel full while it drew in a bit more coolant. Once the coolant started expanding and overflowing I pulled the funnel and put the radiator cap on. No problems since.

If I was in your position I would get the front end of the truck uphill a bit to encourage the air to move. If the pump is not flowing at all and its due to an air gap the gap is likely to be in the pump itself preventing the pump from being in contact with the coolant. I would take the thermostat housing back off and fill the system from there. With the housing off I would pump the fluid inside the engine by pinching off the top radiator hose and then squeezing the lower radiator hose to force coolant in and out. This would likely cause coolant to come out of the radiator housing, the point however would be to dislodge an air pocket or other blockage, so I would do it forcefully a few times before filling, then I would fill it up and squeeze a few times more gently, fill, squeeze, etc until I no longer saw improvement. After that, fill the radiator, fire it up with the radiator cap off and burp as normal.

 

[Flag Gibby]

The manual says it should take 13.2L but it hasnt taken nearly all of that. I didn't replace the housing, it isn't cracked or leaking, just the tstat, and the tstat is installed correctly, looking at it they seem kinda "Joe" proof. Like they only go in one way, and you really cannot mess it up.
Fixing to take the tstat out and put it in boiling water, to see if it opens.

Thanks for your help though. I have been at this for over a week now. Would a weak water pump prevent flow to the heater core?

Sorry about that, when I read your description of the leak I took it to indicate that the T-stat housing was leaking. Honestly I have never seen a weak/bad water pump on this generation yet, but a weak water pump would not prevent flow to the heater core. I would pull the t-stat and fill the vehicle through the housing with the lower radiator hose connected until the coolant wants to start coming out the upper radiator hose at the t-stat housing (leave it connected at the radiator and disconnect at the housing) and then put the t-stat back in and put everything back together and finish filling through the radiator cap. That should take care of your air lock issue and then you should be able to get around 4 gallons in the vehicle (including topping off the overflow tank). Do the typical front+back heater on high with the engine idling after the vehicle gets up to temp for a minute (shouldn't take anymore than about 10 min total at idle). Shut it off and then let the vehicle cool down some and then slowly open the radiator cap and check the level, top off if necessary but usually coolant starts coming out before you get it completely open so it is good and you just need to top off the overflow tank.

 

[Csylvia02]

Ok apparently my question didn't post from the other night, so lets ask again.

If I have to open the tstat housing to try and fill it from there, I have to drain the coolant out to get the level lower than the housing, if I did that wouldn't there be a lot of coolant already that close that it would only fill to that level again?

I stuck a hose in the housing and tried to force water into the areas through the tstat housing and it didn't take long for the water to fill back up.

I have recently jacked the front end of the car up, and it almost immediately filled the funnel with coolant, I didn't pour any into the funnel, I let it down and the level changed a little but not much.

I have pumped the lower rad hose and the upper hose and gotten some air bubbles out but the heater is still blowing cold AC type air.

I think I will have a drain and flush done at a local place and see if that changes anything.

UNless someone has a full proof way to do this without the tools.

 

[Tech By Trade]

The idea is to get that thermostat to open so the fluid can flow past it and fill the air. If you get all the air on the hose side of the thermostat you can burp it out because the thermostat will get to temperature and open due to the fluid being full on the block side.

 

[pzy3339]

At this point I would leave the thermostat housing off and fire it up. If the water pump works it should be pretty obvious. Might be very obvious actually...

Is there any chance the serpentine belt is in the wrong configuration spinning the pump backwards? I don't know if that is even possible. Would likely be an issue if it is though!

 

[Csylvia02]

I used the schematic in the Haynes manual and double checked it against the one the fan housing.

 

[mes882]

I agree with some one above. You have air in the system. Like stated above some vehicals have a bleeder on the thermostat housing right on top crack it open watch the air come out. If not take the radiator cap off leave it off . Start it let it run. Checking the coolent level everynow and then. At some point it will drop as the air come out when it does it usually does it pretty quick. When it does drop add more coolent. This is not a 30 second process. It does take some time. It could take 30 to 40 minutes. I take this extra time to put my tools away and clean up my mess while I wait.

 

[Rickademus]

Hey Cslyvia did you get it ?

 

[Csylvia02]

Hey,

thanks for asking! I ended up taking it to the shop our of frustration to see if they could get the air pocket out. They could not , but suspected the water pump (they do not do repairs just minor maintenance) so that´s what´s next on my list. Had to order it and will pick it up from the store today.
Let´s hope that´s the issue.