A/C Problems Please Help, 110* Tomorrow!

[6 Nebraska IDIs]

Hey guys, my mom complained about her air conditioning not cooling over the weekend so I added a can of R134 to the system. It didn't help, in fact it didn't cool at all after that. Today the pump started squealing when she turned the air on. What happened? Did the pump go bad?
Also, the blower fan hasn't blown nearly as well as it should for years and I know this adds to the cooling factor as well.

 

[sassyrel]

if the system was up to proper charge, before you added a can, and you put a full can in, you may be close to the point of trying to compress liquid---hence the squealing. or--by adding that can--the pressures went higher, and created enough resistance to the clutch or belt, they are now dragging. and yes, you need a good fan to push the air across the evaporator to get the most cooling--only a set of gauges will tell the true story--

 

[DragRag]

Put a set of guages on there, and check the suction pressure, it needs to be between 35 and 40 psi, no more then that. Sounds to me like it is now overcharged for sure. Wash the condensor out very well, it may be impacted. Next check the pressure, make sure the condensor is completly dry when you do this, or it will give abnormally low pressure readings. You can use the cheap suction gauge that you use to charge the system that can be bought at any autoparts store. Do this and report back.

 

[icanfixall]

you can buy a set of gauges onEbay for around $25.00 all the time. Sure, some are more costly too if they are new... If you drop the charge check the pressure switch and the orfice tube. The tube may have some black death in it... If so buy a new pump, evaporator, condnser and dryer....

 

[sassyrel]

you can buy a set of gauges onEbay for around $25.00 all the time. Sure, some are more costly too if they are new... If you drop the charge check the pressure switch and the orfice tube. The tube may have some black death in it... If so buy a new pump, evaporator, condnser and dryer....

there is another way to do this, but you have to have someone who knows how to do it---

 

[6 Nebraska IDIs]

What's the orifice tube?
I dropped the pressure a bit and then started the truck and it was still squealing a bit, clutch popping on and off every second or two revved the engine up and it apparently broke it loose because its working just fine now. I think the pump was froze up, letting the pressure out a bit and blipping the throttle apparently did the trick to get it working. Pressure is now right around 45lbs according to one of those cheapy walmart kit gauges. But anywhere below that supposed pressure and the system wouldn't cool at all.

I spent 4 hours straightening fins in the condenser and then pressure washed it out, I think that helped allot too. Tomorrow will be the ultimate test.

I think the blower motor may be shot even though it still runs it is pulling ALLOT of power through it because I ran test leads straight from the battery to the terminal and it ran just slightly faster but it made my wires so hot I couldn't touch them.

I've been trying to convince my parents to buy the parts and let me do the system myself, even though I really don't know everything about it I think I could pull it off. They keep telling me they don't have the $2000 to put into the new parts to do the job though.

 

[DragRag]

It's not gonna cost ya anywhere near 2k. Your suction pressure is high though. if the condensor is dirty or plugged it will raise the suction pressure also. Of course over charged will do that to. Sounds like you need a new evap blower motor though. If it is not turning fast enough the refrigernat that flows through will not flash off to a gas, and it will slug the compressor with liquid. You have to make sure that all components are working properly before charging. Charging is the very last thing that should be done. To your knowledge was a good vacumm pulled before the initial charge was oput in? It is ok to top off without one, but it must be pulled to a 29.9" vacumm so there are no non condensibles in the system, air and moisture will play serious havoc.

Here is what I would do if it were my truck being an A/C service mechanic for 13 years. I would first and formost make sure you indoor fan motor is working fine, make sure your clutch fan is working correctly. Then I would wash the condensor, pull a vacumm and then weigh the correct factory charge in, not guessing at it will make it right, but you can go by pressure to of course. If you have been running with air and moisture in the system, I would also change the reciever drier to pick up any trash in the system. Let us know how it goes.

 

[tknomaj]

what is high side pressure? But dragrag is right empty system replace orifice tube a variable one is best and when converting from r-12 to r134 the system is to receive 20% less than required for r-12 and check blower motor and resister block because if fan does not move air acroos evaporator it will not cool and pressures will not be correct

 

[Diesel JD]

Sounds a lot like my truck. It was not cooling at all so I spent about an hour of labor and a few buck in r-134a to get the correct pressure and make sure the blower motor was ok and clean all the trash out of the ducting. It still hardly blows but cools real nice. The pressures are a bit too high so I'm going to spring for a new condensor core and orifice tube and possibly pressure switch and receiver drier. Oh yeah he also put a bit more oil into the compressor with UV dye so we can check for any slow leaks in the future. I think you have the temporary fix. As mechanically inclined as you are Sean, I'd think the worst case scenario would be, you pay someone 1/2 hr labor and any environmental fees to discharge and recover the r-12 if it still has freon in it obviously this is less hassle with r-134a. You buy all the parts and do the labor yourself.
New condenser core $100-200
Orifice tube $5.000
Receiver dryer $40.00
Compressor-rebuilt $100.00
Misc. fittings $35.00
Grand total parts $380
Then pay about an hour's worth of labor to recharge and check for leaks labor total: $150
Grand total: $500-600 Nowhere close to 2K, but it might be that if you let a shop do the whole job. If you know how to or want to learn how to, recover refrigerant and charge the system of course it could be more for parts and tools but less for labor and maybe worth it in experience.
Good luck and stay cool.

 

[6 Nebraska IDIs]

Thank you all for all the input. Im gonna keep this an open thread because Im sure Im going to have more questions as we work this thing out.
The truck is a R134 system originally so no worries there. It has always been pressurized and sealed. It does have a leak that I found at the low pressure valve by the drier. Other than that I have not seen any leaks. Leaks are normally easily visible by dirt collecting on them, cant see any of that. I can just see it bubble out of the valve a little.
We have to add a can to this truck about every month.

Another question though for ya'll.
What do I need to pull my own vacuum from an opened system.

 

[tknomaj]

a can a month is not a small leak one can is a pound and that is a major leak change schrader valves in service ports and o ring at low pressure switch and poss low pressure switch also but a can a month is a BIG LEAK

 

[RLDSL]

You have a big enough leak where it's going to be hard to keep a balance in the system. A variable orifice Valve will cool the thing much better than a standard one, it's about $30 more.
Look in the stickys for the article on the heater bypass valve that little trick helps a bunch to cut the hot water. Insulating the evaporator box on the engine compartment side helps a bunch as well

 

[subway]

i just installed ac in my truck a couple of weeks ago from knowing only the basics on how ac systems work. i am surprized it is not that complicated overall. i found autozone had a good price on dryers at $28 and got a pump there for $178. i also got a o-ring pack for $10 and replaced all of them. the rest i pulled from other trucks and a member here.

the blower motor concerns me, motors pull more amperage when they are going bad. if the wires are getting hot from you jumping it its got to be straining the truck wiring and the switch. if nothing else i would address that, a blower motor should not be more than 20-30.

 

[icanfixall]

You can make your own vacuum pump. I did. I used the compressor from a cold water drinkng fountain but any refrigerater compressor will work. When you have the comp removed fom the frig run it and see which sides are vacuum or pressure on the lines. then weld on some fittings and start using it. I just soldiered on my fittings with silver soldier but any soldier will work fine. Lots of broken refrigeraters or freezers out there... Some are even along side of the roads....

 

[typ4]

A later crown vic blower motor ,aka:cop car. has a wicked powerful blower motor. and bolts right in, of course I find this out after replacing mine. Ac is not hard to work on and learn, go slow and be safe, oil in the eyes burns as does refrigerant.