Today my wife called and said the excursion was running hot but cooled off when the a/c was turned off. Any ideas on this? I know the compressor puts a strain on the engine. Anyone have any ideas?

2000 Excursion 2wd with 5.4 V8

 

Sitting still or moving? If sitting still it is a fan issue. If while moving then check cooling system (fluid level, thermostat, water pump, radiator for clogging.) In most vehicles it is a fan.

 

It is when moving and only when you are putting a load like a long hill or rapid acceleration. I'm going to take it in and have the cooling system flushed and a new thermostat put in. Fluid level is fine but looks dingy. It runs normal temp all day long and will blow super cold air as long as you are not going up a big hill or say getting on the interstate or needing to pass.

 

You can take some compressed air and blow off all the bugs, leaves, rocks, etc. off the fins of the radiator by blowing it through backwards. You'll be surprised how much crap gets stuck on the AC condensor, thus blocking airflow to the radiator.

 

I'll give that a shot as well. I looked in the grill and behind the bumper and it looked pretty clean but your idea cannot hurt a thing.

 

You need to look between the radiator and condenser. That area will often fill with debris. It won't come out with air or water without first separating the 2 heat exchangers.
If the radiator and condenser are clean and you still overheat under load, it's time for a new radiator. Flushing usually doesn't remove the deposits. BTDT.

 

Cleaned the condenser and the radiator, amazed at all the junk that came out. I removed the piece above the radiator and condensor and pulled the grille back and washed it with a hose/water. We'll see but i'm still going to take it in and have a flush done on the radiator and a new thermostat put in.

I also washed the k&n filter. That thing was filthy. Question about the fan clutch. When it is cold, should'nt I be able to spin it a good turn? When I spin it I get very little movement.

 

Not necessarily. When cold the fan is usually stiff for a minute or so when you start the engine. There's really no good way to test a fan clutch without an electronic tach and a strobe light.
The best "seat of the pants" test is to check the AC operation at idle. If the AC cools well at idle with the engine hot, the fan is doing its job.
When the clutch starts to get weak, the AC will wheeze out at idle. This will happen long before the engine temp is affected.

 

Yep, it cools just fine when hot at idle. The temps in this thing only creep up with air on under heavy load. If the air is off at a heavy load the temp stays normal. Thanks for all the input. I'll make sure I post when the problem is resolved.

 

What temps "creep up" ECT or the temp of the A/C blowing on to you?
There is a vacuum activated valve on the heater core coolant hose
(pass side under the cowling near the A/C lines) that is
designed to keep the hot coolant out of the heater core when you
have the A/C. Perhaps the gray vacuum line has come off and
is messing with your A/C.

Not sure if all Ex's had this or only those with EATC.

 

MAKE SURE YOU PUT ELC IN...NOT FORD GOLD!! After you are done with the flush you should in stall a coolant filter!!

 

The vehicle temp climbs. It did it today with the a/c off. The temp of the A/C has been consistantly cold. We had to drive it today and on top of that had another issue.

What is ELC? Where does a coolant filter go on a 5.4 Excursion?

 

What are you basing the temperature measurements on? The gage on the dashboard may not be accurate. Are you getting boiling of fluid? Is the catch bottle filling up with coolant? You could have a thermostat sticking shut and it happens all the time. A scangage and maybe other OBD-II readers can probably read the sensor directly and tell you what the actual temp is assuming the sensor is good. Mine stays around 190 all the time accept when cold and then it reads the outside temp pretty close.

I don't think you need a coolant filter. It is an add on thing and more of a thing you do for diesels. There is a certain amount of crap in your cooling system and it does not seem to hurt anything. Pump shaft seals are pretty dirt tolerant. A good flush of the system would be a good idea. When antifreeze goes bad it tends to leave a black sludge behind. Also never ever ever put tap water in your cooling system. The lime in the water will plate out and clog coolant passages in the radiator core not to mention Chlorine, Flourine, Alum etc. But it is ok to drink just don't put it in your radiator or it will rot it ;-) .


Perry

 

I'm basing it off the gauge in the dash. It will climb up past the middle and get almost to the hot (red). Turn off the a/c or turn on the heater and it drops down a little below half on the gauge. It was driven all over downtown Atlanta yesterday afternoon with the a/c on in stop and go traffic and did fine. Parked it due to the little issue with it not starting in "park" and drove around again with a/c on in stop and go and as soon as we hit the interstate with the a/c it ran up hot again. Turned off the a/c and it did'nt move untill I turned on the heater for a minute, then it dropped quickly. I did'nt run the a/c the rest of the way home but up the hills it ran up and then when it leveled out the temps dropped. This weekend it will get a new thermostat and then i'll take it up and have the coolant flushed out. Then I have to figure out this neutral safety switch/cable adjustment problem. With 148k on the clock i'm starting to think it is time to move on.

 

I'm thinking it's time for a radiator, to be honest. Pretty classic symptoms.