Expedition heater woes, warm then cool air

[joedmti]

Blend Door

go to heatertreater.net

They show you to get to the front blend door, but not the rear.

For get the blend door, eyeball that water pump.

Anynoodles, the rear blend door is accessed from the inside of the truck.
Pull the third seat out, and start digging the plastic and trim out of the driver side rear wheel well.

The heatertreater.net video will show you how to rip and strip your front interior to replace the blend door.
Before you go wild and start the tear down, I suggest you get an eyeball on the blend door. And while you are there, you can feel the heater core and see if she gets hot. To get a visual on the front blend door, just drop the glove box door, get out your dremel tool, cut the back of the glove box out,
then cut the black plastic plenum across the top, the vertically down the right and left side, then remove the 2 bolts w an 8mm ratchet.
Once the plenum has been removed, you will see the blend door on the left.
Turn the heat/cool knob, see if the door opens and closes. (My guess is it is)
Check the heater core, its on the left, bet she's cool.

Put the plenum back, and get yourself some silicone to seal it in place.......

 

[mangus64]

I'd love to believe it's the water pump, replace and I'm done. I did however have good coolant flow through the clear heater hose I put in but maybe the coolant isnt mixed well (warm but not hot) due to worn water pump fins?

It certainly makes sense and would explain why the rear heat is roughly the same temp, lukewarm.

Also my top top radiator hose/ lower radiator hose are warm and certainly not hot.
Expy has 140K and its the original waterpump.

Thanks for all the help!

 

[ksoren1779]

Easy Water Pump Test

Do you of a way to check the water operation with out having to remove it to check the fins?

Kevin

I may have a water pump problem:
1998 Ford Expedition 4WD, 4.6L Engine EFI-SOHC, V-8
180K
Heater blows hot air for a short time then air turns cooler.
Has front and rear climate control, same problem front and rear
Engine does not seem to get to operating temp range. Temp guage gets about 1/4 the way, I have a non-contact infrared thermometer and constantly check the engine temp near the coolant temp sensor and it barely gets over 170 degrees.
No signs of heater core leaks. With engine warm hose to heater core 135-140 degrees and hose out about 120-125 degrees.
Have removed center console; can view Blend door actuator motor shaft move (seems like 180 degrees) when moving temp control from full cold to full warm
Normal coolant system flushed
Heater cores not flushed independently
New coolant temp sending unit
3-New thermostats
Radiator Hose gets hot (170) and doesn’t ever seem to be pressurized
A/C works great front and rear

 

[Racenut]

Change the pump.

When at idle you may be observing "good" flow ( or even reving the motor a little ), but when you are out driving worn impeller fins will cause cavitation and you will not get the correct heat transfer and flow will go down.

For both front and rear systems to be having the same problem is going to rule out any blend door issues since they are seperate from eachother with seperate controls for each. This being said the only two other items that can cause these conditions ( because you are getting some heat when sitting ) would be a stuck open thermostat or a water pump also since you have already changed the thermostat multiple times that narrows it down to just one option.

 

[joedmti]

Impellers not visible.

Kevin,

My mechanic shot his non-contact laser pointer thermometer doo-hickey on both of my radiator hoses. They were 165 degrees Farenheit. He said they should be up at 210 degrees F, or almost at boiling point. Bought a 50 dollar water pump, he put it in for a hundee, problem solved.

I just came back from my driveway, I dont see fins on the pump..........

Hope you get it fixed......

Joe D

 

[joedmti]

Whats the temp on the hoses

Mang,

Any idea what the temp is on the top and bottom radiator hoses?
If its not over 200 degrees, you'll never get heat.

If you dont have one, you can get one of those laser pointer non-contact thermometers for less than 40 bucks.

Did you take the truck to a mechanic that specializes in radiators, water pumps, etc?

 

[Racenut]

Mang,

Any idea what the temp is on the top and bottom radiator hoses?
If its not over 200 degrees, you'll never get heat.

If you dont have one, you can get one of those laser pointer non-contact thermometers for less than 40 bucks.

Did you take the truck to a mechanic that specializes in radiators, water pumps, etc?

I have an after market temp gauge installed into the intake coolant passage and during cold weather (15 F - 35 F ) on the interstate I run about 140F and in the summer I only run 180 F on the interstate and 200 F in city traffic and my heater will blow you out of the truck.

Anything over 100F and you will feel heat the main thing like you said is the flow. If the impeller is worn down it will cavitate and not transfer the heat to the coolant the way it should plus the flow of the coolant will slow the higher the rpm's.

 

[mangus64]

Bought a new pump today, Napa, $62.

You guys are telling me that the metal fins of these pumps wear off? If so I'll know for sure when I pull my original one out.

How involved is it to change the pump?

Thanks again guys for all the help.

Mangus

 

[Racenut]

Bought a new pump today, Napa, $62.

You guys are telling me that the metal fins of these pumps wear off? If so I'll know for sure when I pull my original one out.

How involved is it to change the pump?

Thanks again guys for all the help.

Mangus

The hardest part of the job is usually getting the mechanical clutch fan loose from the water pump snout. Make sure you do this while the drive belt is still on, it will aid in holding the water pump pulley in place while you get the fan loose.

 

[ksoren1779]

Thanks for the reply. If the water pump is not fucntioning efficiently would'nt the engine overheat? Engine temperature never gets over 180 degrees.