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Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4565
Experience:  Fully qualified / self employed garage technician in the UK
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I have a Mazda 3 TS2. Although the air con works, there is

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I have a Mazda 3 TS2. Although the air con works, there is like a grinding noise coming from under the bonnet when it is on. Mazda tell me it is 'normal' however an independent mechanic says it's a dry bearing. Is it 'normal'? The car is under warranty so I want it fixed if necessary before it runs out!
Submitted: 1 year ago.
Category: Car
Expert:  Robert replied 1 year ago.
Hi..there.. Shouldnt be normal to hear such a noise with the A/C on - you will hear the A/C clutch kick in aswell as the fans but not grinding - Firstly you'll need to determine if the noise changes when the A/C is either on or off..If thats has already been determined and only occurs when the A/C is active - then it fairly likely the A/C compressor internally or even just the clutch pulley is at fault..the centre clutch pulley only activates when the A/C is commmanded on and this is what spins the compressor..when commanded off the A/C pulley is just free wheeling..its like a magnetic clutch...But either way you'll need to investigate further..if its just the pulley then you may just get away with just replacing that on its own..if the compresssor internally is creating that noise then you need the whole unit plus new gas and dye...I do hope this helps..if you need to ask anything further then just continue before you rate
Customer: replied 1 year ago.
That's great, thank you. The car is in for an MOT next week and the warranty runs out shortly after that. Do you know if the problem is covered by the Mazda warranty? It does only happen when the air con is on. I have asked them to investigate next week. The friendly independent mechanic I got to listen to the car did say sarcastically that because it was under warranty that's why Mazda didn't want to fix it! Is it expensive? I just want to be confident about what I'm asking them to fix next week and not be palmed off as an 'ignorant' female if you understand what I'm saying. I want them to put it right before the warranty runs out!
Expert:  Robert replied 1 year ago.
If its still under manufacturer warranty then it should be..sometimes you need to stand your ground with them but normally mazda are fairly good when it comes to work like this..or elaborate the fault with regards ***** ***** noise becoming louder/unbearable if you like or the A/C as far as your concerned is simply not perfoming at a satisfactory level as should be expected of it.....But it can be a bit expensive if the whole compressor needs replaced as involves having to drain the gas already in the system then new seals on the lines then once the compressor is installed.then you have to evacuate the system and ensure the vacuum holds for period of time usually 15minutes before you even add new gas/dye back in..once thats done then you need a HVAC electronic sniffer to ensure the seals on the new compressor arent leaking any gas..then test the temperature of the cold air coming into the cabin....If its just the clutch pulley then you dont have the work above you could simply just lower the compressor enough to get the clutch pulley off and replace it.with a new one .and that should be that...thats why its best to be sure first by investigating further..
Customer: replied 1 year ago.
OK. So I'll stand my ground and say the noise is louder than when I had the car serviced in February and I know it should not be making that noise. I'll say it is not normal and ask them to investigate to see if it's the compressor or the clutch pulley and fix the problem. Does that sound as if I know what I'm talking about?!
Expert:  Robert replied 1 year ago.
Yeah.. i mean basically as you describe the A/C compressor shouldnt be creating that noise anyway and it certainly doesnt sound normal to me and im not there to hear you've had independant inspection done with the same conclusion...ive heard hundreds of A/C compressors on all types of cars over the years and and all types of failures grinding is usually fair sign of internal problems unless the clutch on the front is bad which is easy to diagnose....the upshot is that if a bearing is bad within the compressor and is left un fixed is will just sieze up and maybe run the risk of breaking the belt leaving you stranded...but you really need to stand your ground and explain considering you have brought up the issue before that the problem is becoming more serious and needs dealt with or investigated at least until your satifisfied that the problem is cured..
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Customer: replied 1 year ago.
Thank you. I really appreciate your help and can now go into Mazda confident that I understand the problem and need them to fix it.

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