02 overheat-or-not overheat

[allpro]

Ok guy's your going to think I am on some kind of weird drugs with this one.
I recently bought 02 Ranger 2.3, It has this really bazar problem. very intermitent. It only happens when the AC is used and does occur very frequently when used in "MAX Air" and not quite as often when used in just AC. The problem is this...the temp gauge will "Peg" to hot. I don't mean a slow crawl to hot. But just slam over to hot. The AC quits working and a short while later the temp will come Right back to normal. Not a gradual drop but just as if you had hit a switch. Once it starts doing this while driving with the AC on in either mode it continues this cycle. Now when I say the AC quits the blower continues to run. But it starts blowing warmer air until the temp drops back to normal range. The AC Comp. stops running as well as the electric fan behind the radiator.

What I found I can do is turn the ignition switch to off a couple of moments later turn it back on and everything is as it should be. Using clutch to resart engine.

The temp problem does not show up when the air is off.

The temp sensor for the gauge has been changed, the clutch fan has been changed. As well as the thermostat. It has been determined that under normal running conditions the block temp is about 240 deg. Also the truck infact is "NOT overheating" This is a error on the gauge reading.

And all this somehow effects the temp gauge and ac.
I often can not get back to the forums so If you have a answer I can be e:mailed @ allproaudiotv@intcon.net as well as your posting a reply here.

 

[BrooklynBay]

Welcome to this forum! That temperature is way too hot. You should replace the thermostat, and flush the cooling system. You said that the thermostat was replaced, but what temperature thermostat did you replace it with? The radiator could be partially clogged. There are special cleaning agents which could be used to loosen particles that are clumped inside of it. It would have to be immediately flushed so as not to clog the heater core. Was the water pump ever replaced?

 

[Red FX4]

He said the engine is not overheating and that it is an error on the gauge. It sounds to me like an electrical wiring issue or possible a grounding problem. I don't know these systems well enough to guess where that problem could be.

 

[karenhetzer]

I just sent a pm to the original poster of this thread hoping he's found an answer because he's not crazy....I also have a 2002 Ford Ranger and I'm having the same problem with my gauge needle spiking suddenly to H....which scares me and I immediately turn the heater on, and whether its that, that makes it go back down or not I'm not sure, but another 10mins. or so and it does it again.
I'm sitting in a motel room now for the second day while mechanics try to figure it out. It is running hot about 235. So far I've had the thermostat replaced, the fan clutch replaced, the water pumped checked, they have it on pressure overnight, but while I was there and it was hooked up it was maintaining pressure. I asked about the radiator.....they felt it was too new to be the problem (2002) but I guess will check it if nothing else presents itself to be the problem.
I'm so frustrated and upset over the expense so far and no answer to this....does anyone have other ideas what to look for?
They also pulled the spark plugs and check for the possibility of cracked block (I think I was trying to listen in, but some stuff I don't understand.

 

[BrooklynBay]

Maybe the radiator is partially clogged?

 

[trucku]

You have an electric fan behind the radiator and a clutch fan?



Backflush your radiator. My 02 had lots of scaling and debris when I flushed it out after I bought it.

 

[allpro]

did that way back early on. was very dirty. but did you grasp that when this happens I can turn the ignition switch off and right back on and the temp goes right back to norm? I leaning toward the other sensor, the 2 wire one that goes to the comp. all other electrical. I.E. fuse box connections and PCM have been ck'd for loose fuse conections. Some were found. And problem seemed better for a time. Our ambient temp has been crazy. But today it got up into the mid 90's and the thing went nuts. the AC would warm and just blow cool not cold and the temp would be fine. Then the temp would peg. turn the ing. off and back on and the temp comes back to norm. and soon the ac will start working again. maybe not.