Truck runs hot when AC is on

[miichael]

Ok guys got a question for ya and heres the story. I bought a 1999 ranger 3.0 had blown headgasket. guy before me put head gasket sealer in radiator to try to fix the head gasket with no luck. i got it tore it down replaced both head gaskets and thermostat and all gaskets and been driving for 3 months now. i flushed the radiator good about 10 times running water in it and then put 50/50 mix in it and drove it ever sense. however the AC was low on freon and clicked on and off ever couple secs. Truck never ran hot not 1 time while driving. well i bought a few cans of freon from walmart and decided to try to charge the AC. before the compressor just kicked on then right off over and over so i knew it was low. i put 1 full can it in and it was showing full charge in the middle of the full mark, blowing cold air and compressor was on and running all time while in park. Well i drive it down road and compressor kicks on and off ever 5-7 seconds. still blows ice cold air. well i think well maybe its still low on charge. i add another can and fill it to the full mark right below the alert before it goes into the yellow so i know its completly full. again after driving it compressor kicks on and off every 5-7 seconds but blows ice cold air. now after deiving it around town the other day i noticed it start run hot after the AC was on while driving. never run hot before but now it is. So my first thought is the radiator is still stopped up thats what making it run hot, but is the ac doing right? is it suppose to kick on and off every 5-7 seconds? could that be why its running hot or is that how its suppose to do and just need new radiator?

my 96 explorer when ac is on the compressor never kicks off. V8 5.0.

i read online that its suppose to kick on and off the save on gas and when accelerating its suppose to kick off but does yalls rangers kick on and off ever 5-7 secs constant while driving? now sitting still in park it runs longer.


i know i should replace the radiator with that sealer being in it but i just dont want to fork out for a new radiator if my AC isnt working proper. turn ac off and heat hand starts to come down.

so AC messed up? or need new radiator?

 

[Rearanger]

First I'd want to find out what the actual high/low pressures are in the A/C system using proper gauges and not the colored gauge on the re-fill can. You may have overfilled it. The A/C system is designed to cycle on/off to prevent freezing (blocking) of the evaportator, this is controlled by a temp sensor on the outlet of the evaporator. Every 5-7 seconds seems excessive. You can insert a digital probe thermometer into an outlet vent and watch the air temp go up and down as the system cycles on/off. You also probably have a Max A/C position on the selector switch that will alter the min/max temp range of the A/C cycling that is usually designed for high heat and humidity.

 

[miichael]

well with it on max A/C it gets ice cold. way colder than my other vehicles. but it never freezes up or stops blowing cold that i can tell so far. it gets freezing cold inside truck and under the hood the low side gets very sweaty and cold to the touch. the high side gets VERY hot and hot to the touch.

I think maybe there is too much pressure on high side causing it to get too hot? i dont have gauges for high side but im not sure?

 

[miichael]

ok this morning i went out and put the gauge on the low side without can hooked to check pressure. it said 30 psi on low side with outside temp being 80 degrees. so im thinking the system is still low? the manual with my recharge kit says at 80 degrees it should be 40-45psi. does this sound right? low system charge?

 

[8sechonda]

my older ranger kicks on and off like that every 6-10 sec at like normal driving at 55. ac blows so cold it blows fog out the vents lol.. but mine doesnt run hot, not sure why it would run hot w the ac on and not run hot w it off.. havent ever ran into tht problem

 

[xr75er]

Miichael, Hate to tell you this but you probably have over filled your system. The only proper way to tell the charge is to do a full evacuation of the system then use the proper gages and a scale to fill the system. A shot of florescent dye will help locate the leak. As for the heating up of the engine check the bottom to half way up of your rad as the truck is running .If the rad is only hot for the middle up then the bottom section is probably plugged due to the rad/ gasket sealer. When the load is off the engine it dosen't need that much air to cool it down. More than likely it settled out in the rad. Go to the bone yard and pick up a replacement. Hope this helps

 

[miichael]

well according to the gauge its still low on freon?? only got 30psi at 80 degrees outside?

 

[James86]

Thats why I took mine to a shop to have it done

My 1999 3.0 blows ice cold air and has never overheated in the 3 years i've owned it. Remember, the AC radiator goes in front of your cooling radiator, so your sucking hot air form the AC rad through your engine's rad. If your A/C system is putting out a LOT of heat, that may be a problem. Crud in your collant system wouldnt do you any favors, so the combination of the two together may be what the problem is. Best bet is to take it someplace and have it evacuated, filtered, and recharged correctly. Everyone I know who tried it themselves with a wallymart kit or something ended up blowing out their A/C compresser or something in a year or two. I think I paid maybe 60 bucks and mine was only 1/3 full.

 

[Big Jim M]

Howdy Mike

Everyone has missed the point here.. Yeah you do need to visit an A/C shop.. but the point I want to make is HOW HOT IS IT? NO ENGINE is hot as long as the coolant is staying inside the engine! If it ain't puking the coolant out the overflow it AIN'T hot!
So tell us a little about the hotness... How hot does it get.
Also you didn't tell us where you are.. That would help us to know what temps you are seeing daily.
I have run overfilled a/c systems many times without overheating my engine.
I'm thinking you might be overly sensitive to your themperture gauge.
Big JIm

 

[miichael]

it gets 3/4 way up with AC on during hot day then i turn AC off and let it come down. Compressor is on and off every 5 secs. during normal driving no AC hot day its between 1/4-1/2 on gauge little below half. i mean its not in the red by no means with ac but its 3/4 way up. i live in NC and its been around 90-98 lately.

think it may be low causing it to work extra hard??

ac is ice cold and works great other than on and off every 5 secs and causing heat to go up

 

[James86]

Even the owners manual says anywhere in "NORMAL" is fine, and that's 7/8ths the way up the gauge. Mebbe you are a hair paranoid. I will say though that mine stays right in the middle once its warmed up and doesnt really move at all whether the A/C is on or not. Carry a juge of 50/50 for peace of mind if you want, but like Big Jim says, unless you're puking coolant your fine. Also, if it WAS overheating, the "CHECK GAUGE" light would come on. My intrepid had a gauge and a dummy light with chime. Your computer should know what temp is correct since the CEL will sometimes trip when the sensor is bad.

 

[miichael]

so kicking on and off ever 5 secs is ok? i was thinking it should run longer?

 

[Big Jim M]

As I wrote above... YOU NEED TO VISIT AN A/C GUY!
Big JIm

 

[miichael]

i think i fixed my problem. heater core is stopped up with the sealer that guy put in it. i bypassed heater core and drove it for 3 hours and never got above half mark. even let it idle in 96 degree weather for 30+ minutes never overheated. tried flushing the heater core with water hose and brown trash water came out but the flow is limited. water pressure from the hose alone wouldnt just run through it without the hose on full blast .

just glad its not running hot anymore and ac is ice cold.