New A/C Compressor Rattling Noise

[blk95lumina]

Hello.

I completely overhauled the A/C system on my 2000 RCSB silverado 5.3L w/ a lower mount Delphi compressor (H6). I replaced the compressor, condenser, suction/discharge hose assembly, orifice tube, and accumulator. I flushed the solid metal line from the condenser to the accumulator and flushed the evaporator. Vacuumed for 45min. @ 30 Hg and then checked system after 30min. of sitting and no leaks. I put 3oz. of PAG 150 in the compressor, 4oz. in the accumulator, and 1oz. in the condenser and charged up using 3, 12oz. bottles. The system holds 29oz. of 134a, so I think the 36oz. is more than enough to compensate for the hoses and what does not make it out of the bottle.

Here are the measurements:
Ambient 65F
Humidity 80%
evap line in 39F
evap line out 39F
vent air temp 42F
Low side press. 43 psi
High side press 170 psi

It seems to me the system is healthy but for some reason the brand new compressor makes a slight chattering or rattling noise like you would expect from low oil, but I used 8oz. of PAG 150 and the system appears to be fully charged.

Only thing I did different from a standard A/C job was use a variable orifice tube.

Any thoughts as to the chattering or rattling noise of the new compressor?

Any other tests or measurements I can try?

Thanks.

[j cAT]

Originally Posted by blk95lumina

Hello.

I completely overhauled the A/C system on my 2000 RCSB silverado 5.3L w/ a lower mount Delphi compressor (H6). I replaced the compressor, condenser, suction/discharge hose assembly, orifice tube, and accumulator. I flushed the solid metal line from the condenser to the accumulator and flushed the evaporator. Vacuumed for 45min. @ 30 Hg and then checked system after 30min. of sitting and no leaks. I put 3oz. of PAG 150 in the compressor, 4oz. in the accumulator, and 1oz. in the condenser and charged up using 3, 12oz. bottles. The system holds 29oz. of 134a, so I think the 36oz. is more than enough to compensate for the hoses and what does not make it out of the bottle.

Here are the measurements:
Ambient 65F
Humidity 80%
evap line in 39F
evap line out 39F
vent air temp 42F
Low side press. 43 psi
High side press 170 psi

It seems to me the system is healthy but for some reason the brand new compressor makes a slight chattering or rattling noise like you would expect from low oil, but I used 8oz. of PAG 150 and the system appears to be fully charged.

Only thing I did different from a standard A/C job was use a variable orifice tube.

Any thoughts as to the chattering or rattling noise of the new compressor?

Any other tests or measurements I can try?

Thanks.

could have too much refrigerent in it . rattles usually mean the compressor is trying to compress liquid or low oil. another would be not enough refrigerent to compressor , but the pressures are good for the low air temp.

try slowly purging the ac and see if it improves. could also be air in the system. oil absorbs mositure and it takes some time for the air to boil off under vacuum.

[fiserman]

Haven,t worked on these systems for a while but you do need to stay close on the manufatures recommendation cause its not hard to put to much freon in. Pay closes attention to head and suction pressures running to high. J cAT is right to much freon can make it rattle but also a lot of people forget to check compressor to see if it comes with oil already in it. Differant manufactors sometimes check there compressors differantly. Some leave oil in them and some take it out. If you did not check to make sure oil was not in it you may have to much oil which will make it rattle and may show up as high head pressure. I would check everthing else first but that could be a possible problem. They may tell you were you bought the compressor it has no oil in it ,but they also told me that to and they were wrong.
Good Luck Fiserman