leeboy

Few days ago, I noticed my AC wasn't as cold as usual, I checked my charging gauge , and it was a little bit below the middle line. Usually it's a decent amount over the middle line. Put a charging gauge on it and it was charging at 13.4-13.8 V kinda fluctuating. It is a 2 year old re-man. Last time the alternator went my AC would only blow hot air. A mechanic said the charging is normal. Today, I was bootin around and saw my truck was starting to get warm . As soon as I turned the AC off , the truck cooled down and the charging gauge went back up to about midway . Turned the AC back on , same thing. So, my question is , is 13.7 V ( and fluctuating) be too low and affect the AC and the overheating issue?

BigIron70

Sounds like you may have a fan clutch issue or possible plugged up radiator. Does the fan clutch spin freely engine not running, also feel across radiator engine off if there are any cool spots on radiator? core restrictions if there are cool spots at operating temperature. Check also for oil and dirt accumulation from the crankcase vent tube lower part of radiator at the engine side of radiator could be blocking air flow across radiator. Also check your battery connections and load test the batteries.

dubc2323

yeah it would, 13.7v is not enough of a charge and will affect your ac.

NE frmhnd

You should be running 14 volts. Shouldn't affect the coolant temp though. Blow out the radiator, especially in front of the fan hub. You need air flow through the radiator and across the fan clutch to make it work.

leeboy

Thanks gang, I'm going to change the alternator this weekend . Can I spray the rad with some engine degreaser and pressure wash it? The old owner, has some of that fine black mesh in front of the rad , kinda reminds me of black door screen.

leeboy

I tried giving my fan a spin with the engine hot or cold... And it's hard to spin. No matter how hard I try it only spins as hard as my hand makes it go. Stops instantly . My buddy's Dakota , I spin it and hen I let go it almost spins a revolution . Is mine normal?

dubc2323

I would say its shot...probably your overheating problem...and as far as cleaning your radiator.. degreaser would be fine but I wouldn't pressure wash it ..I would lightly spray it with air first then degreaser and then just a regular garden hose to rinse it off. high pressure would bend all the fins.

gorms

My fan has a pretty strong drag on it as well, I don't think they are supposed to freewheel.

Make sure your tensioner is putting enough on the serp. belt, pulleys are clean and not oily, belt is in good shape etc. If the fan is trying to pull in you should hear it, pretty loud. Belt could be slipping over it, along with your other pulleys.

leeboy

When my truck is idling, what is that intermittent click ( quite loud) that is kicking on and off. Also, is there any sure way to test the clutch fan?

dubc2323

mine spins about 1/8 of a rotation on it's own but it's not hard to spin. As far as the clicks go...if it's just when you start it, then it's just the grid heater and will stop as soon as it's warmed up or you go about 20 mph.

KATOOM

If you have never relocated the blowby vent bottle hanging in front of the engine, then it sounds like what you're experiencing is a plugged radiator. What happens is the engine fan causes such turbulence that it pulls the oily air vapors coming out of the blowby bottle and throws them all around in that area, which causes the radiator to be covered in oily residue that collects dust, dirt, and debris. This happens over time.....but will happen unless that bottle is moved to a location farther away from the fan. One indication that this is the problem is that the A/C doesnt work good during idle or slow speed driving but gets colder the faster you travel.

Also, getting under the truck and trying to look for this blockage wont work. You can try some mild degreaser/cleaner but probably whats necessary is just to remove the radiator and clean it right. Why cleaning is hard while still mounted is because most likely all you do is shove the garbage in between the radiator and intercooler. Also, IMPORTANT.....do NOT use high pressure washers or sprays. It will quickly ruin the radiator fins by blowing them over.

In regards to the clutch fan..... Yes, a clutch fan will cause poor A/C function but are far far more rare than the plugged radiator condition. The OEM fan clutch is very good so if it is worn out then spend the money and replace it with OEM since the over the counter parts store fan clutches are not strong enough. The OEM engine fan on these engines pulls 10,000 cfm at 2000 rpm. Thats A LOT.

One way to test the clutch fan is, with the engine off, open the hood and grab a fan blade. It should feel very resistant to turn. More so when its warm out too. Attempting to turn the fan by hand will result in about 1" or so of rotation. There should also be zero movement in all directions. No play whatsoever. If this is what yours is like then its most likely just fine. The other easy identification that the clutch fan works is if you hear it when the outside temps are hot and you're running the A/C or towing. Since the OEM engine fan pulls 10,000 cfm at 2000 rpm, its easy to hear the roar.

leeboy

On the weekend , it was about 86 degrees out, had the AC running, noticed the temp gauge was gettin a little above the middle line, turned the AC off , and down went the temp gauge. Waited a bit, kept driving, did the exact same test and once I shut the AC off , the temp gauge comes down . Weird

nothingbutdarts

Not weird: Your A/C compressor in a sence is a heat pump, you have the compressor, condensor (sits in front of the radiator), evaporator (it's in the heater box and freon (very low boiling point) in the complete system.

The way your A/C works is (generic explination) the compressor pumps the freon thru the syst. and there is an orafice tube that drops the syst. pressure, after the orafice tube the pressure is droped so much the freon gets like 28 degrees, then it passes thru your evaporator, the heat in the truck cab is absorbed into the evaporator evenutually boiling the freon and it taking the heat with it, the condensor in front of the radiator gets all this heat and can get as hot as 275 deg. this hot air WILL warm up the air going to the radiator to some degree. What you are seeing when running the A/C is this heat from the condensor raising the temp. of the coolant. If your cooling syst. is working efficiently it will show warmer on your temp. gauge, but will not affect the cooling of the engine accept being a few degrees warmer all the time the A/C is working than when the A/C is not working.

leeboy

Cool .... Great info everyone , thanks

Busboy

As has been mentioned your radiator is probably partially plugged from dirt sticking to the oil from the crankcase vent bottle, relocate the bottle and clean the rad, don't pressure wash as has been mentioned it will bend the fins. Also there should be nothing right next to the condenser so remove that bug screen and move it up front either on the outside of the grill or just inside but not on the condenser.