Picked up my mums car and the air con compressor sounds really noisy as if the bearings have failed.

Disengage it and there is still a bit of noise but hardly any, as the compressor kicks in then the noise is back. How often should the compressor kick in/out when on.

Hello,

how many miles do you have on the clock?

I had mine having the same sound when it kicks in, but at the 40K service i had the belting changed and the sound is now gone

you could also count to 7 and its on, 7 and its gone... if this helps lol

its my understanding the a/c compressor is supposed to be quiet now that I have replaced my belt and tensioner (and that noise has gone) I can hear the compressor...its even louder with my stethoscope


its not the bearings as the noise goes away when the compressor clicks off and the belt is still spinning
ive no other issues with the a/c system it delivers ice cold air and was re gassed feb 2020 I fear that it being a 10 year old compressor its on its way out that being said im not surprised with the amount of other parts ive already fitted!!!!


so.... obviously I don't want to shell out hundreds on a brand new one (if I have to......I will) but there are plenty 2nd hand units on ebay I just need to get the system evacuated by a garage first then replace and have re gassed
but as always im asking for some imput/advice

Does anyone know what oil the compressor uses? I’ve just started looking but it’s a tad confusing

Baglady1990 said:

Does anyone know what oil the compressor uses? I’ve just started looking but it’s a tad confusing

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Pag oil usually for r134a system but it's injection with the gas so not really a DIY job to add more

chris3234 said:

Pag oil usually for r134a system but it's injection with the gas so not really a DIY job to add more

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Ahhh so it’s done with the re gassing Chris? I’ve been looking at 2nd hand compressors some say only oil 8 but from what I’ve read oil 8 has been replaced by oil12??

Baglady1990 said:

Ahhh so it’s done with the re gassing Chris? I’ve been looking at 2nd hand compressors some say only oil 8 but from what I’ve read oil 8 has been replaced by oil12??

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I think from what I've seen before pag46 seems to be the most common oil viscosity but not 100%
But it's definitely not a DIY job as you need to correct equipment to inject the oil along with the r134a gas it's also common to add a UV due along with the oil to make any future leak's easyer to find

chris3234 said:

I think from what I've seen before pag46 seems to be the most common oil viscosity but not 100%
But it's definitely not a DIY job as you need to correct equipment to inject the oil along with the r134a gas it's also common to add a UV due along with the oil to make any future leak's easyer to find

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makes sense it’s just me watching hard to find YouTube videos.. not even sure what make of car it was ? think I’m going to get a new compressor and either fit it myself or just get the garage to install and re gas it!

chris3234 said:

I think from what I've seen before pag46 seems to be the most common oil viscosity but not 100%
But it's definitely not a DIY job as you need to correct equipment to inject the oil along with the r134a gas it's also common to add a UV due along with the oil to make any future leak's easyer to find

Click to expand...

I’ve read that you should replace the receiver/dryer after changing ? What is this ?

I think the Drier is part of the condenser on the 500.

Moisture is an aircon units worst enemy, the drier/ receiver collects this and liquid refrigerant to prevent it from entering the compressor. AC compressors will only compress gas, liquid refrigerant will destroy them.

If you do need to break into an AC system you should replace the drier ( in theory anyway)

The pag oil is only topped up when replacing condenser, evaporator or compressor whilst recharging with refrigerant.

Bodga said:

I think the Drier is part of the condenser on the 500.

The pag oil is only topped up when replacing condenser, evaporator or compressor whilst recharging with refrigerant.

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Indeed it is! Since my condenser was changed feb 2020 it should still be good I do have another question though as I’ve decided to buy a brand new compressor I’m still unsure about the re gassing procedures

Do they just use my number plate to find the correct gas ect if so would it show pag 8 when in actual fact the new compressor will be pag 12 I may be talking complete jibberish but from what I’ve read the two are not interchangeable and could actually harm the new compressor ect ....

Remember to get any seals needed they tend to be green O rings.

On your slam panel or bonnet it should state the gas, which is 134a pre 2016 I think? And on the same sticker it should say the oil too.

The oil is dependent on what compressor is fitted, like you say, but the oil is also used for lubricating seals around the system on vehicle AC.

RalphM said:

Remember to get any seals needed they tend to be green O rings.

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Yes I’ve ordered those! ?

Bodga said:

On your slam panel or bonnet it should state the gas, which is 134a pre 2016 I think? And on the same sticker it should say the oil too.

The oil is dependent on what compressor is fitted, like you say, but the oil is also used for lubricating seals around the system on vehicle AC.

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I’ll have a look and see if it’s there thank you for your help I’ll update if I have any issues ?

Bodga said:

On your slam panel or bonnet it should state the gas, which is 134a pre 2016 I think? And on the same sticker it should say the oil too.

The oil is dependent on what compressor is fitted, like you say, but the oil is also used for lubricating seals around the system on vehicle AC.

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I’ve just had a look there is nothing referencing the type ... there are two silver labels one on each a/c pipes with 2 different long numbers maybe this is it?

All I’m concerned about is the wrong gas going in a new compressor and causing issues down the line
I suppose I’ll have to speak to the garage first with my car being a 2011 and a new compressor if they were to use the old type it would basically rot my new compressor

Bag lady, the only gas they will use on a 2011 car is 134a. The the gas used in newer cars, post 2016 ish costs a fortune compared with 134a. And the pipe connections are different for the newer gas.

The only possible issue would be lack of PAG oil, which they should top up when replacing the compressor.

Replacing O ring and pressure testing before recovering all moisture from system before regassing the correct weight. All garages advertising a regas service should be able to to this with their eyes closed so nothing to worry about.?

Bodga said:

Bag lady, the only gas they will use on a 2011 car is 134a. The the gas used in newer cars, post 2016 ish costs a fortune compared with 134a. And the pipe connections are different for the newer gas.

The only possible issue would be lack of PAG oil, which they should top up when replacing the compressor.

Replacing O ring and pressure testing before recovering all moisture from system before regassing the correct weight. All garages advertising a regas service should be able to to this with their eyes closed so nothing to worry about.?

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thank you sorry for being a pain I just like to understand before going forward but thank you again for explaining I get it now ?

Bodga said:

If you do need to break into an AC system you should replace the drier

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:yeahthat:

Moisture is an A/C system's worst enemy. Good practice calls for the dryer to be replaced every time the system is opened; some even say it should be replaced routinely every two years. Pretty much everyone in the business says it should always be replaced if a new compressor is being fitted; fitting a new compressor without also replacing the dryer would almost certainly invalidate any warranty on the compressor.