I have done some searching and I think I have the heat issue narrowed down. I just want to double check with people here with a little background on the car.

The car has 150,000 miles on it. We got it with 32k. The coolant has not been changed since we've owned it. I just checked and it looks pretty cruddy, but it is at the proper level.

The heater does not blow hot. I can turn the HVAC system off for awhile and turn it back on and it will blow hot for about 15 seconds. This makes me think that the front heater core is plugged up. The back air acts the same way, so I think that heater core is plugged up too. Is it likely that they are both plugged up given the condition of the coolant? The temp. gauge comes up to about halfway, so I think the thermostat is still good. I feel like I'm due for a cooling system flush and try to unclog the heater cores. What is the best way to go about this? Should I change the t-stat at the same time?

Next, it is throwing a P0430 code. Again, the car has 150k miles and has not had the O2 sensors changed. It still averages 15.8mpg. Is it likely that I just need to replace all 4 O2 sensors and that will solve the problem? About 15k miles ago a few of the coil packs went out and we only changed the bad ones and their plugs. The car does not feel like it is running rough at all. Every now and then if you are accelerating from a stop the engine will hesitate, but that doesn't happen very often. There is a big rattle from the driver's side of the car sometimes when the car is in gear and at idle. I haven't had a chance to get under there and figure out what that is yet.

Also, the car ran regular unleaded gas for about 30k miles. If that affects anything.

Sorry to ramble, I'm just trying to think of anything that would help in the diagnosis.

Thanks

 

One bump before I start digging into this to see if anyone has any thoughts.

 

I'd say you are w*a*y over do for a coolant flush. (There are any number of posts on this forum on how various folks have done the flush.)

I would suspect the blend door is causing your issue, but it is a pain to replace. (When you turn on the EATC the module forces the blend door to its maximum travel to figure out where the door is. That might be why you feel hot air for a short time. Do some searches and there are a number of posts regarding the temperature of the inlet and outlet heater hoses to determine if the core is restricted. But I'd do the flush first - old antifreeze can become quite acidic and you don't want it to eat away your heater core or your head gasket!)

Replace them if you want, but the PCM periodically will run tests on the O2 sensors by forcing one bank or the other to run way rich for a few seconds and then way lean to see if the O2 sensors can put out the maximum and minimum voltages, and measures their switch time in milleseconds to determine if the O2 sensors are still within spec. If not, the PCM will cough up a code indicating the issue.
The P0430 code indicates that when the PCM ran a test on the cat performance on Bank 2 it found that the cat efficency was below the accepted threshold. Depending on how long the vehicle ran with bad plugs or COPS, (were the ones you replaced on the driver's side?) that could ruin a cat, as could antifreeze leaking out of a head gasket, or...

if it ran leaded gas, that would kill a cat.

 

It never ran leaded gas, just lower octane. The anti-freeze killing the cat sounds interesting. Is there any way to tell if the acidic anti-freeze has eaten through the head gasket? Would I see it in the oil?

Thanks

 

Well I finally got down to work on the car today. I ran it until it came up to temp. and then kicked the heat on. I ran the heat for a bit on low and it stayed hot. When I kicked the fan up to high I could feel the air cooling down. I put the fan back on low again and the air started warming up again. I went out and felt what I am pretty sure are the heater core hoses and there was a significant difference in the temps. between the two. I killed the heat and the outlet hose warmed up a bit.

I really feel like is is a heater core issue rather than a blend door issue now. After reading the other recent thread about the 01 Expy, I'm a little nervous messing with it won't help now. The coolant was last changed about 2 years ago when a new radiator was put in. The overflow bottle has some crud in it because it had been awhile before that.

Maybe I can hook a water hose up to the return hose coming from the core and blow some of that stuff out backwards? Either way it seems like I am due for a flush.

The rattle from the cat. (?) only happens every now and then; I can't make it happen when I'm actually working on the car. Is there any good way to very this is what's causing me CEL? Or just any good way to make it rattle? (ha).

On a different note, a mech. crawled under the car the other day and said that the ream main seal is leaking. I looked and that does appear to be the case. He said that you HAVE to take your car to the dealer to have it fixed because normal shops can't separate the engine and transmission? I have some pics to see if it does indeed look like the RMS is leaking.

Pics later, can't seem to get em to work right now.

Thanks

 

The rattle at the cat could be the heat shield being broken at one of it's supports.
The rear main seal requires the removal of the transmission and flywheel to get to the seal itself. It will be fairly expensive to have the job done at a shop and if it is only an occaisional drop of oil here and there I would leave it alone. If it is puking oil it must be changed asap.

 

Yea, it's not bad. I'm just going to leave it alone. I am going to do the radiator flush tomorrow though. Since I feel like the core(s) are clogged I was going to hook the water hose up to the return line and see what I could blow out backwards. I have heard that these heater cores are fragile and I'm a little nervous about putting too much pressure on them. What is a good gauge to see if I'm getting enough pressure to unstop anything in the core but not enough to break anything?

I figured after that I would pull the therm. out and flush the system with water a few times then fill with chem flush and then use one of those t fittings to completely flush with water and then add coolant and a new therm. (just want to make suure the procedure hasn't changed)

Here are some pics of the tranny area with the oil on it; just for fun so yall can see how much is leaking.

<a href="http://s30.photobucket.com/albums/c324/bigred177/?action=view&amp;current=IMAG0014.jpg" target="_blank"><img src="http://i30.photobucket.com/albums/c324/bigred177/IMAG0014.jpg" border="0" alt="Photobucket"></a>

<a href="http://s30.photobucket.com/albums/c324/bigred177/?action=view&amp;current=IMAG0015.jpg" target="_blank"><img src="http://i30.photobucket.com/albums/c324/bigred177/IMAG0015.jpg" border="0" alt="Photobucket"></a>

 

What temp. therm. do y'all normally put back on there? It looks like there are a few options.

 

I think stock is 180* or 185*

 

That looks more like a transmission front pump/torque converter seal leak to me. The staining seems to be a reddish-brown like ATF. Either one is expensive to repair because of labor time.

Here's the specs from Ford. I would just use household water pressure to flush the system . If it's going to leak it is better to find out when you are flushing or testing the systrm than when you are 500 miles from home with the family.

Here is something else to consider adding to the mix, in the red text.


SECTION 303-03: Engine Cooling 2000 Expedition/Navigator Workshop Manual

SPECIFICATIONS

--------------------------------------------------------------------------------


General Specifications Item Specifications
Capacity 4.6L a L (gal) 17.9 (4.8)
Capacity 5.4L a L (gal) —
Coolant mixture with water 50% 2
Pressure relief cap opening pressure kPa (psi) 110 (16)
Pump pulley ratio 1.3
Water thermostat start to open temperature 87-91C° (188-195F°)
Water thermostat full open temperature 100C° (212F°)
Lubrication
Ford Premium Cooling System Flush F1AZ-19A503-A ESR-M14P7-A
Premium Long Life Grease XG-1-C ESA-M1C75-B
Cooling System Stop Leak Powder
E6AZ-19558-A ESE-M99B170-A

a Ford Premium Engine Coolant E2FZ-19549-AA or -B in Oregon, F5FZ-19549-CC, Canada: Motorcraft CXC-8-B or equivalent meeting Ford specification ESE-M97B44-A (green in color).


Torque Specifications Description Nm Lb-Ft Lb-In
Cylinder block drain plug 16-24 12-18 —
Fan blade to fan clutch bolts 17 13 —
Fan blade and fan clutch to water pump pulley 55 41 —
Fan shroud screws 9 — 80
Degas bottle bolts 9 — 80
Radiator support bracket bolts 30 22 —
Transmission fluid cooler fittings 20 15 —
Water outlet connection bolts 25 18 —
Water temperature indicator sender unit 20 15 —
Water pump bolts 20-30 15-22 —
Water pump pulley bolts 20-30 15-22 —

 

Great, thank you

 

I just did a heater core flush on my 2000 Expedition. And if your Navi has the same quick disconnects that mine does. Just as a precaution, pick up Teflon washers for them. Most parts stores have them under the AC parts for our trucks. If you lose any of those teflon washers, you will just spew antifreeze like a cut artery. No one stocks them, but both Autozone and Napa carry them. Don't want ya to go through the headache I went through. There's 1 5/8th O-Ring and Teflon washer per disconnect.

 

Got it done. I didn't even try and mess with those quick connects. I bought two of those Prestone t-fittings and a length of heater tubing and spliced it into my heater core lines from the front. When I back flowed the heater cores about 2 gallons of nasty mess came out. Several fills and dumps later the water was clear and I ran the flush through it. A few more fills and dumps later I put the new coolant in. Heater is blowing hot again. Thank goodness. So far I have only been able to get about 3.5 gallons of water and coolant in there. I added it to the reserve bottle and drove around until it was up to operating temp. I know there wasn't much water in the block because I undid the driver side block drain. After I drove it the coolant bubbled down some more so maybe it just needs time. The heater didn't blow hot and cold like there was an air bubble though.

 

I'm probably gonna do the same thing this weekend. My heat has had a mind of it's own after flushing the heater core, it was Hellish hot after for a few days but now, it does what it wants and checked tonight after an hour drive, the out from the heater core is cool again. I have 1 Prestone kit, I may grab another, save myself the headache, of the quick disconnects again. Did you flush to the reservoir or flush and drain from the drain spout itself? There are 2 Block drains, but one is behind the starter or there abouts, a project too cold to tackle as of late, either would be a project in 30 degree's. If you missed one drain on the block, and with the water that didn't drain from the engine, and coolant line to the rear and both heater cores, I'd figure 3.5 Gal out of 6 would be about right. I'd take a guess draining on a down hill would yield a bit more.

 

I filled it up from the tank every other time when I was filling with straight water, then put the flush chem in from the reserve. I blew out the heater core lines the best I could with air before I filled the car with coolant. I probably didn't get all of it out of the back lines though. Those prestone t-fittings make it a very easy process to do.