Ok I see a lot of people with heater problems with Expeditions. I have a 2000 with the 4.6 that I recently purchased. I have tried everything that I can think of to get the heat to work. The blend doors are fine. I am not getting flow through the heater cores while the engine is running. I have flushed both cores and can get water to flow through from every direction with the hoses disconnected. The lines headed to the cores get very hot, however the return lines do not. I am confused because I can run water through the cores with a hose. Is it possible that the cores are clogged and just letting water through, but not enough to heat it up? I have replaced the thermostat and water pump. The next step I am planning is to replace the rear heater core, since it is easier to get to than the front. (if it works at least the baby will be warm!) Any suggestions would be appreciated!

 

Yes it is possible. The fact that the return lines do not get hot is a good indication that there is minimal flow through the cores. You can confirm this by turning the heat on but keep the blowers turned off. If the return lines get hotter with the blowers off, then it's a restricted heater core(s) issue.

This is of course assuming that you checked and the coolant level is up where it should be, and the engine is up to full temperature.

 

"alloro" brings up a good point, allot of people overlook the coolant level assuming it is fine, I have the same thing so many times, people say they have no heat, they think it is a bigger problem than they think. If the coolant is low there won’t be enough flowing through the heater core and it won’t warm up. In your case if all else fails I would just replace the heater core. In the long run I think it’s the best option.

 

Ok I replaced the rear heater core today. Rear heat works great now. Good news and bad news about that. Good news is, it fixed the problem, and I know what I need to do to fix the front heat as well. The bad news is..... fixing the front heat. Gonna be interesting to find the time to tear the entire dash out of my Expedition while taking care of our 6 month old and preparing for Christmas. Oh well, guess I'll get to it eventually, at least the car gets warm now, considering the 20 degree temp and snow we are having now. Thanks for your input.

 

Would you mind posting how you replaced the rear heater core? I'd sure like to know in case I ever have to do that job.

 

Ok i have now replaced both front and back heater cores. The heat works great! The rear core is pretty easy to replace. To replace the rear core, first you should drain the coolant, then remove the plastic molding on driver side wheel well near the back tailgate. you will have to remove the trim from behind the rear seats and under the back tailgate, then the whole left side should be able to be popped out. You will have to use a large torx bit to remove the 3rd row seatbelt from the top of the rear frame and the 2nd row seat belt from the bottom of the drivers side rear door. This will allow the plastic cover to pull back far enough to gain access to the heater core box. Remove the black cover by removing the small black screws along the top and sides. Once the cover is removed, you should see the core. It is the small radiator that has the two black hoses clamped to it. Simply remove the clamps from the old core, and attach to the new one. It is a good idea, to flush these hoses before installing the new core. You will want to remove the hoses from the front engine compartment and run water through to the back. (make sure you have something to catch the dirty water in, clamped a water hose fitting on the end of the hose and attached a small piece of water hose leading to a bucket.) You should check the blend door's while you have the unit off for any cracks in the plastic as this is a common problem with expeditions as well. Hopefully this makes sense.

As for the front, the center console and dash must be removed. I found a nice step by step video on you tube showing all the fasteners that need removed. Even with the video, it took me all evening and the following morning to complete the front.

 

You still deserve a good pat on the back for replacing both cores so quickly.

 

I have a 2000 Ford Expedition, XLT, 4WD, V8, 5.4 Liter.
I had heater core bypassed, changed, am re-assembling, but need diagram for where all hoses connect on block, etc.
Either post here or email to mesark@yahoo.com

Thanks,
Bill

 

Do you have to connect hoses for front heat only or front and rear heat?

 

Thanks for your help, alloro. Need to connect both, he left all the front core hoses, there's a hose clamped behind engine, on top, the other goes to pass side, low end of firewall. I assume those are the supplies to the rear?

 

Hmm, I've been trying to find it but the service manual doesn't show much.

 

I figured the manual wouldn't, that's why I asked.

MAYBE, it doesn't matter? I mean, as long as water FROM the supply splits to one side for both front & rear, and the same for the returns? Simple plumbing, get rid of the Ford NON-easy connectors, go old-school with Home Big-Box copper Ys and Ts, 5/8 tubing???? Whaddya think?

 

That's probably what I would do too.

 

Thanks for your help, alloro, headed out for plumbing now.

 

Well, copper fittings don't work, got 2 plastic Ts from the Boys of Pep. Should finish inside later today.
Thanks again.