ojosdestranger, I'm sure you know this, but the reason the engine sees more heat with the AC on is not the "load" on the engine, although the compressor does cause some, it due to the fact that the AC does not make "cold", it only moves heat.
It moves the heat out of your cab and sends it to the small radiator in front of the main radiator.
Which means that the main radiator sees hot air coming into it and has to work harder to transfer the heat from the engine to the hotter air. So, anything that inhibits its ability to do that will cause overheating when you run the AC.
The problem with your truck is that the cooling system is marginal at present for some reason and gets overloaded when the AC comes on.
Now, since you have done the obvious, we need to look at other things.
Timing problems would cause this, but are very unlikely in a modern engine. You would be getting all kinds of codes being set.
I'm betting on a flow problem. Either coolant or air. Air is easier to check, so lets got there first.

Get a light and look between the air conditioner radiator (known as a condenser) and the main radiator. Just because you have not gone off road, does not mean that trash has not gotten sucked up in there. I once found a plastic bag in there.
Next, examine the fan clutch. Look especially where the shaft goes into it. ANY oil stains there are grounds for replacement in this case.
For a close range driver that does not overheat, you can let that slide for a while, but in your case, we can't.
This is my favorite suggestion for your problem by the way. It sounds like a marginal fan clutch. Don't let anyone tell you that the fan does not do anything at highway speed. My '89 F-250 has the super-cooling package with the big fan and clutch and radiator. When I am driving along at 70 with the AC on, my temp gauge creeps up to about half way, and then the fan clutch kicks in with a gradual roar. The temp gauge moves back down and fan roar fades out.

If the fan clutch does not have any oil leak, get a water hose with good pressure and spray water all the way through both radiators from each direction. A garden hose, NOT a pressure sprayer!!
Even a small amount of dust and dirt can cause a large difference.
Then, crank the engine up and let it idle with the AC on high. When the temp gets high, shut it off and immediately pop the hood and try to spin the fan. It should not be locked up, but should stop instantly when you let go and be hard to turn. If it coasts at all, replace the clutch.
If all that fails, try letting the engine cool, drain a small amount of coolant out until you get it below a row of tubes.
Start the engine with the cap off and watch for the coolant to start flowing through the tubes when the thermostat opens. You should be able to rev the engine slightly and see the coolant shoot out the tube. If not, its time to look at the radiator or water pump.
All that assumes that the radiator is the type where you can see the tubes through the cap opening.

If the air flow checks seem ok, try looking in your yellow pages for radiator shops. Most of these places are specalists and can do measurements on flow and what have you and determine where the coolant flow problem is without having to replace good parts.

J.

 

Ranger250Center... Thanks for your detailed post. I appreciate you taking your time to help a fellow "Ranger Fan".

Today, during lunch break, I stopped by AutoZone and told the story to one of the guys. He was extremely helpful and said "I know what it is". So we popped the hood and he noticed the "FAN CLUTCH" is not tight like it is supposed to be. He ran and stopped the engine and asked me to look at the fan still spinning after the engine stopped.

So tonight, I will be replacing the "FAN CLUTCH" and get ready to go out of town for the Memorial Holiday.

I will post results later...

Thanks!

 

Sounds like you nailed it. If the engine is dead cold, a fan may continue to spin briefly when you turn it off, but if there is any heat on the engine at all, it should stop and be hard to turn. The clutch has an oil in it that acts as a liquid clutch. When the air coming through the radiator is cold, the oil is closed off by a small shutter type valve and cannot reach the vanes inside. As soon as the air heats up, the valve opens and lets the oil into the other side of the clutch where it couples the two halves of the clutch together and makes the fan turn at engine speed.
After you replace it, listen as you drive down the road with the radio off, and you may hear the fan noise change as the temp changes.
J.

 

Good Point!
Fan noise - yeah, I remember my Bronco doing that in the summer. I knew it was doing that because of the heat.
Currently, I don't hear the fan noise on my Ranger. Maybe (crossing fingers & praying) this is the solution.

Thanks again!

 

Check engine light came back! After a new EGR Valve. Still code P0401! The guy at the parts store told me to clean the ports with B12 spray cleaner. I did all that last night.

I also replaced the Fan Clutch and noticed it was a lot tighter now. I'll keep everyone posted on the overheating after my Memorial WE Travel...

 

Alright... Friday, I drove from North Dallas to South Texas and the temp rose to 3/4 just like the pic from prev. post...

Saturday, took it to Mexico to get the radiator pulled out and get the radiator lines cleaned. They charged $18 and that included the labor to remove from the truck. It is amazing how they actually clean the lines...

I will post the results from a long drive (in the 97 degree heat) back home...
I will also post pics...

 

Well how did it do on the return trip????

Did cleaning the radiator out, fix er up ???

 

Today is Saturday... Will post the results on Tuesday along with the pics of how they cleaned the radiator.

Up in Dallas, people just want to sell you a NEW radiator vs. fix what you have OR they want to do a radiator flush with chemicals...

 

Problem Solved!
It was a clogged up Radiator.

Check out the cleanup process in Mexico. Well worth the $18 (which includes removal, cleanup, reassembly, and checkup)

Pics...

http://www.supermotors.org/vehicles/...=34577#content

 

Glad you got it, and you got out cheaper than I did. Good job.

 

Good to hear you seem to have it put right.

OK, so fill us in on how did a 01 Rangers radiator gets so clogged up internally, that flow was restricted????

Have you been changing your coolant on time as as specified, or was this the OEM coolant charge????

Would be helpful to know some history, in case there are coolant changing procrastinators out there reading this thread, maybe it'll give them the incentive to look after their system, before it goes belly up!!!!

 

This is the same process used in the states. It's called "rodding" out the radiator where the metal rod is inserted in each of the tubes. $67 in this area. jim d

 

HISTORY:
I bought my 2001 Ranger used from Ford in Mar 2004. It only had 21K miles on it. I figured, wow, 3 years old with 21K - that's 7K per year. So I jumpped on it.

Never changed anything other than regular maintenance stuff.

Never worried about anything since all was well till the Overheating after 62K miles.

HISTORY LESSON -
It still had the OEM coolant.
All you out there - do the Radiator Flush with your garden hose (with the "T") every chance you get. It is a lot cheaper than buying a new Radiator at $160+ or spending what they charge in your area for "Rodding" $70+.
I was lucky enough that I had a trip planned during the Memorial Weekend to be close to Mexico where they charged $18 which included cleaning and labor to remove/install/check the Radiator.

GO DO A RADIATOR FLUSH, BEFORE SUMMER KICKS IN...
GO DO A RADIATOR FLUSH, BEFORE YOU GET STRANDED IN AUGUST IN JEEPERS CREEPERS...

-Stranger

 

OK Stranger, good feedback, some guys wouldn't have fessed up, but confession is good for the soul, RIGHT!!!!! lol

Yup that puppy was ready for it's first cooling system flush when you bought it, so we can sort of judge how long it'll take for one to clog up & begin to seriously affect cooling when neglected.

So you guys out there reading this, that are guilty of cooling system neglect & you know who you are, listen to what Stranger said, ger er tended to, before it lays down on ya in some god forsaken place!!!!!!

Stranger, from the way you worded your posts, I'll bet you haven't changed the tranny fluid, power steering fluid, or brake fluid either.

If you haven't changed them, why not see to them too, now that you have such a good start, with the cooling system, bet your ride sure would appreciate it!!!! It'll make her work real good & last a long time!!!! lol

I'm due for another P/S & tranny fluid change out shortly, did the cooing system & brakes last fall on my 99!!!!

 

I am keeping my eye out for a coupon to change the Transmission Fluid since I already passed the 60K miles.
I didn't know the Power Steering and Brake fluids need to be changed. How do I do that?