I had to change a valve core. I just evacuated the a/c system and recharged the system. filled the system with almost 3 can of r134a.
Compressor runs but doesn't seem that cold. the low pressure side seems to be near 20psi. Hi side is near 100psi. Doesnt seem like there is enough pressure.
Is 3 can enough refrigerant? Is something else wrong? TIA
How many ounces per can? Look at the filter drier sight glass under the hood between the radiator and the bumper. You should have a bubble here or there in idle. If it is heavily flashing with bubbles you are low on charge. If the sight glass is bubble free, you have a restriction either in the drier itself or the expansion valve.
Something to try. If you have a restriction, let the pressure equalize, then start it up, the high pressure side will run extremely high at first start up then rapidly lower in pressure after a few minutes due to lack of flow. It almost sounds like you have a restriction but it is very hard to tell unless being right there. If you have zero bubbles in the sight glass and no cold air I would almost certainly say it is a restriction. As long as your compressor is pumping and from your pressure readings it most certainly is. 20 psi suction pressure is low. So is 100 psi head pressure for R134 Medium temp application.
If the method above checks out, I would try raising the head pressure up to about 140 psi. The suction pressure/low side changes under load as does the head pressure/high side. However, the ambient temp for the high side remains somewhat the same as the ambient temp doesn't change. Therefore, it is far easier to charge by head pressure rather than suction pressure which is constantly changing under load. Try taking it up to 140 psi head pressure.
the air is cold at start. It isnt cold enough after I drive around to battle the summer heat.
I did notice that the high side line is cold until the dryer. then the other side of the dryer line is ambiance temp.
taking up the head pressure... so do I rev the engine to take it up to 140? or do I add more refrigerant?
Is it possible that the 12 oz can dont actually have 12 oz in it?
the air is cold at start. It isnt cold enough after I drive around to battle the summer heat.
I did notice that the high side line is cold until the dryer. then the other side of the dryer line is ambiance temp.
taking up the head pressure... so do I rev the engine to take it up to 140? or do I add more refrigerant?
Is it possible that the 12 oz can dont actually have 12 oz in it?
Classic symptoms of a restriction. Look at it this way, refrigerant cools and boils when high pressure liquid is passed though a metering device such as a TXV. No matter where a restriction in the system may be, you will have a huge temperature drop across the point of the restriction. It sure sounds to me like you have a restricted filter drier and it is now acting as the txv as it is metering refrigerant too early in the system. Lucky for you it is a cheap part.
Try this; if you have more than an 11 degree temperature drop between the inlet and the outlet of the filter drier, it is a restriction. The filter drier is a core type device of porous rock made to trap moisture to prevent restrictions. Sounds to me as if it did its job and cannot trap mositure any further. Maybe this will help. Stay cool . As I am posting this, it is 107 degrees at my house and the power has been out for hours....
I swapped out the receiver drier. Pulled vacuum again and recharged. I'm getting 30psi/230psi now. Ambiance temp was about 85 degrees. The high pressure line on both side of the receiver drier is warm now. getting good cold air output. This was at night tho.. So real test is high noon at 90+ degrees temp later today.
I swapped out the receiver drier. Pulled vacuum again and recharged. I'm getting 30psi/230psi now. Ambiance temp was about 85 degrees. The high pressure line on both side of the receiver drier is warm now. getting good cold air output. This was at night tho.. So real test is high noon at 90+ degrees temp later today.
I swapped out the receiver drier. Pulled vacuum again and recharged. I'm getting 30psi/230psi now. Ambiance temp was about 85 degrees. The high pressure line on both side of the receiver drier is warm now. getting good cold air output. This was at night tho.. So real test is high noon at 90+ degrees temp later today.
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