mark_simon

Hi,

I have a 96 runner and lately I have noticed that the AC is not getting that cold, especially in very warm weather 90+. Anyway its all original and running 134a.

My question is I am looking at buying the recharge and doing it myself. Should I buy just the can with 134a. Do I need to buy the oil charger, do I need the gauge. Or should I just buy the can that has the 134a, oil and gauge and be done with it? The one with all 3 is 25 bucks from Kragen.

Also do I need to evacuate the whole system before I recharge? Anything else I should take into consideration before I do this?

Thanks for your help.

Ironmike4x4

Just take it to a LICENSED MVAC technician. They have the proper legal equipments to recover, vacuum, and recharge it.


Edit: Just to answer your question. Yes you do need to evacuate it, but how are you going to do it with out a machine? It's illegal to vent it into the atmosphere. Also you have to pull a vacuum to determine if there are any leaks in the system. If no leaks are found after the vacuum you have to add whatever amount of oil you've recovered and then recharge according to manufacturer's specification.

mark_simon

Thanks for your reply.

I assume there are no leaks, just due for a recharge. Why is evacuating the system necessary?

Obviously I am trying to avoid a large bill if I can do it myself. Also I would never evacuate myself.

superjoe83

if there were no leaks then you would never have to recharge it, you have a very small leak some where, evacuating is necessary to remove moisture, air and any other contaminates, and to see if the system holds a vacuum

Ironmike4x4

Technically you are not supposed to "top off" refrigerant. Ideally the refridgerant is supposed to be permenant as long as there are no leaks or system failures. Evacuation is necessary to pull out the existing refrigerants and oil in the system, but a vacuum is necessary to pull any other contaminants and to check for leaks.

graybeard

Mark, just buy a 12oz can of 134A and add it to your system. 12 ounces should not be too much to over charge your system. If after adding the freon and it's still not cooling enough be careful when adding a second can as it could overcharge. Check your suction line (the larger line)for coolness and condensation. The discharge line will be hot so be careful. When adding freon you must use the suction line with your A/C running. If your lucky you should be good to go for several more years depending on how bad the leak is. Most leaks are in the evaporator or condensor coil and will cost a small fortune to replace either coil.
Good Luck,
beard

Ps, 134A is ozone friendly.

Ironmike4x4

Yes, but you can still be fined by the EPA if you knowingly recharge any A/C system and it's leaking.

mark_simon

gray- thank for your reply. I thought that over the years an AC system would normally discharge, so i never thouhgt I have a leak. Still not sure. the AC does get cold, just not as cold in very hot environments. Still does the trick though.

I'm not sure If I should leave it alone, or maybe stick a can in like you suggest. I definately dont want to make it worse.

Is there a write-up to add freon?

rimpainter.com

Also, make sure the engine cooling fan is working properly. To test, simply attempt to turn it after shutting the engine off (full operating temp). It should not spin by hand at that point.

I doubt this is the problem though.

Tomsriv

Although it isn't a bad idea to start fresh, you don't need to purge the whole system. The receiver/dryer (the round canister in front of the radiator with the sight glass) is designed to hold contaminants and moisture. Eventually it will get full of contaminants, but most last the lifetime of the vehicle. Most of the 30 year old muscle cars I worked on growing up still had the original receiver/dryer on them.

mark_simon

thanks for the tip

tonkapilot

Don't just blindly dump a can into the system. Get a guage from Autozone and check the pressure first. If you overcharge, the system will have the same symptoms as undercharge and won't cool at all. Only way to get it right is with a guage.

Second the opinion that there has to be a leak somewhere if the system is undercharged.

shovelhead

The gauge will tell you pressure but not when the system is full. Use the sight glass on the reciever drier and charge it untill there are no bubbles.Also charge vapor on the low side (big line)Also it is normal to lose some refrigerant at the compressor seal. check the connections and lines for an oily residue that is your leak

mark_simon

I turned on the AC this weekend while watching the glass on the reciever drier ( the cannister looking thing by the grill). by the time I got tot he front of the truck I was still able to see bubbles. This cleared in about 10-15 seconds.

does this mean it is low?

Tomsriv

My understanding is that their should not be any air in the system. I would say it is low, but I agree with the above posts that you need a gauge and a specification for the pressure range before you add a can.

MTL_4runner

This is not something I would recommend doing yourself. Have a good garage that works on AC's pull a vacuum on the system and if they say you need to replace parts you can do so at your home then pull a vacuum again to ensure there is no more leaks (vacuum should hold for at least 15-30 min with no loss of vacuum psi). Then have them fill it back up to proper pressure with 134a (they should only charge you for the freon added to the system, not total amount system holds).

This is not to say you can't recharge with those little kits you get, but the results are definately not guaranteed and if you didn't fix the leak, you'll need to get another kit (no way to recover the freon). When I used to work as a mechanic we had quite a few people come in after trying to fix their own systems with those kits (a few even did more damage by over-pressurizing the system too far). Even to this day that is one of the few things I bring to the shop to have done.

shovelhead

Once again, a gauge will not tell you if the system is full or not. R134a is measured in lbs as in weight. Not as pounds in psi. When you watch the sight glass do the bubbles stay gone after you run the system? and does the compressor clutch cycle on and off? the clutch is controlled by pressure switches (high and /or low pressure) and by a thermistor switch ,which detects the temp of the evaporator. also ckeck the heater control valve to make sure it is not allowing hot coolant through the heater core as this will raise the temp in the hvac box