Hello,

Couple days ago I have started to hear some grinding noise from my engine. I hear it when:

- Warm engine (never heard it with cold engine)

- 1500rpm (or more but at constant rpm)

- I neutral or in gear never mind I hear it (even when standing still)

This sound repeats in cycles of few seconds, and a word best describing this is grinding. Every time it happens rpm gauge needle drops a bit and then returns to normal(e.g.1500). Here is a video that I recorded so everyone can see and hear it: http://www.youtube.com/watch?v=vAquY6WT5R8.

Could this be anyhow related to MAF, because my car has recently became little sluggish. I have tried to clean MAF with electrical contacts spray and medical alcohol, but unfortunately this didn't help and the only option is to change it with new one.

Any help would be appreciated.

I have no mechanical experience or training.. but my first guess would be it sounds like a pulley bearing is on it's way out somewhere?

Do you leave the air con on all the time?

Does anything cause it to change rhythm?

Edited 19 April, 201016 yr by Rob.

I have no mechanical experience or training.. but my first guess would be it sounds like a pulley bearing is on it's way out somewhere?

Do you leave the air con on all the time?

Does anything cause it to change rhythm?

Air con OFF or ON it does not make any difference. I put pressure on gas pedal and keep it constant. Same sound happens when driving and when standing still.

Aircon needs re gassed

Aircon needs re gassed

Hi, thank you for your reply, but can you give me some explanation? Does lack of gas in AC system can cause rpm drop regardless of if AC is ON or OFF? Again, I'm open to any suggestion.

Hi, thank you for your reply, but can you give me some explanation? Does lack of gas in AC system can cause rpm drop regardless of if AC is ON or OFF? Again, I'm open to any suggestion.

The type of aircon pump used runs all the time (no magnetic clutch on it), even when off it runs at 2% capacity, but the pistons still move inside the pump. If it's low on R134a gas it will also be low on oil, as the oil is mixed in with the gas.

Here is an update.

Although I said that it was not related with aircon ON or OFF, I was wrong. Today I've tried running engine steadily at ~2000rpm and engine was grinding, then I turned AC ON, rpms drop to 1500 (which was grinding threshold) and grinding sound was gone. Then I drove with airconn ON and I could not hear grinding. Tomorrow I will go to check aircon gas.

Another thing that confuses me is that rpms drop significantly when I turn aircon ON (2100 -> 1500), but what confuses me more is that when I turn aircon OFF rpms don't rise, it stays at 1500.

Hopefully I will have more information after checking aircon gas pressure.

Thank you all for your help!

Edited 20 April, 201016 yr by miranc

The type of aircon pump used runs all the time (no magnetic clutch on it), even when off it runs at 2% capacity, but the pistons still move inside the pump. If it's low on R134a gas it will also be low on oil, as the oil is mixed in with the gas.

Hi, finally I have caught some time and went to mechanic to check aircon, and yes it was low on gas and very low on oil (so he said). He changed the gas and oil, but unfortunately I still hear the same irritating grinding noise, from engine when on 1500+rpms. And when I turn aircon ON, grinding stops.

It is really tough to determine where the noise is coming from, because when listening from the outside of the cabin you cannot hear the grinding. What worries me more is that grinding is somehow related with normal engine work because when it happens rpms drop by ~100.

Edit: Ok, finally buffered up the youtube vid (slow internet atm) Thanks! I shall try my car in a bit to see if it is this, I doesnt wound the same but it sounds similar..

Instead of starting a new thread I shall steal this one and hopefully it may be the same issue...!

Ok, so when Im not hoofing it and driving eco style, I do 1st to 3rd or 2nd to 4th, and the usual 2nd to 3rd.. on occasions when it is on low rpm changing it makes a burring noise around i'd say 1k? it lasts for 0.5 secs at most, I think its more of the moment I lift the clutch or soon after. When I hoof it around or driving less economical its fine and fun.. could it be that Im working the clutch too slow and making the flywheel not grip or something? Strangely it happened a couple of times when my bro drove it, but less frequent happens when I drive..

Im not sure if it is the air-con issue as mine is going v cold still.. and recently had a 'service' from the dealer I bought it from (possibly hasn't done anything to it tbh lol).

(I assume the stutter is because of that gasket valve I read on here changing 15mm to 9mm or whatever.. I've got the links etc but it doesnt annoy me too much to worth changing it).

Edited 27 April, 201016 yr by JLneonhug