AC ON deceleration increases 1.8TSI Gen 3

[clutchtime]

Hi,

 

Just an observation I made, when the AC is on, the engine decelerates a whole lot quicker and there's a sort of a weird sound like something is straining the engine a lot when I rev with the AC on. Just wanted to know if this is normal. Engine is brand new, 910 km on the ODO. 

[SWBoy]

The AC can take up to 5bhp, so that extra load will increase deceleration.

 

You could be hearing the AC compressor?

[clutchtime]

On 4/14/2018 at 16:19, SWBoy said:

The AC can take up to 5bhp, so that extra load will increase deceleration.

 

You could be hearing the AC compressor?

Thought so too mate so I proceeded to do some tests. On cold start if I turn on the AC, no whining so nothing. It seems to only happen after everything is up to temperature. And it becomes more pronounced on longer drives. Its more like a whining sound, doesn't really sound like the compressor, maybe something isn't bolted down correctly? Its a new car so I can get it all straightened out without too much hassle, just need to know the exact cause.

[conn]

The compressor whines with cheese as long as the car requests cold air. It can be heard really well while stationary and reving the engine 1200-1700 rpm. If you turn off the AC (there is OFF button on the center console) the whining stops. After you put it back to Auto, then whining will return.

 

I have gone through the stealer few times, but they do nothing about it - working as intended.

Edited 18 April, 2018 by conn

[Woland]

I have exactly the same whining on my 1.8. At almost 130k km I was concerned it was a defect coming, but if new cars do the same it's good.

[clutchtime]

3 hours ago, conn said:

The compressor whines with cheese as long as the car requests cold air. It can be heard really well while stationary and reving the engine 1200-1700 rpm. If you turn off the AC (there is OFF button on the center console) the whining stops. After you put it back to Auto, then whining will return.

 

I have gone through the stealer few times, but they do nothing about it - working as intended.

Compressor whine maybe, I tried the fan on only without the compressor and there is a set of sounds I heard which seem to be fine. Switching the AC on makes the sound more prominent and hence my suspicion. Ill drive it around a week or so and if persists will show to the SA at the workshop. I have a lot of creaking in the car especially going over bad bumps, more towards the left rear, nothing mechanical for sure, its a plasticky sound, any idea how to remove that?

 

 

[conn]

9 minutes ago, clutchtime said:

I have a lot of creaking in the car especially going over bad bumps, more towards the left rear

Interesting that you hear it by the rear.

 

My front creaked like crazy after stoping over night. Well crazy is overstated, but after going on the first ride of the day the creack was there - goes away after bump or two. My fix was at the dealer where they applied some grease to the bushings.

 

Let SA look at the bushings.

[paulsoava]

There may also be a fair bit of noise coming from the door seals. I too thought it was bad bushings (on my old Octavia II) and the tech checked them out then greased the seals. It was magic, my car was as new! The current Octavia III has the same issue so gummipflege is my friend.

[paulsoava]

As for AC on cold start even though the button on your dash os ON somehow the system chooses to really go on only if needed. So if it's cold outside you might simply be using plain old ventilation regardless of what setting you chose.

[clutchtime]

On 4/18/2018 at 19:02, paulsoava said:

As for AC on cold start even though the button on your dash os ON somehow the system chooses to really go on only if needed. So if it's cold outside you might simply be using plain old ventilation regardless of what setting you chose.

Mate its 35C here, never dips below 25C in the winter too, summer time now so AC usage is high. Im still experimenting with when the sound is most pronounced but it might seem like the compressor when after all.

[clutchtime]

On 4/18/2018 at 17:05, conn said:

Interesting that you hear it by the rear.

 

My front creaked like crazy after stoping over night. Well crazy is overstated, but after going on the first ride of the day the creack was there - goes away after bump or two. My fix was at the dealer where they applied some grease to the bushings.

 

Let SA look at the bushings.

Hmm, interesting that your smoothens out after a bump or two. So the sound is mostly heard when im going down to the basement parking, the ramp does a full circle with a HUGE speedbraker (The long ones with a smooth gradient) on it, interestingly the sound from the rear is heard mostly then, that and I suspect the sunroof something might be loose. Ill show it to the SA and ask him to grease the bushings as well. All sounds plasticy though, nothing suspension like. Any thoughts apart from the door seals?

[clutchtime]

So after taking a trip to the service centre, they've told me they'd need to change the sunroof since its creaking a lot and that it'd take 3 weeks for the part to come.

 

On a side note, I have an iPhone thats connected via bluetooth to the car, in the middle of my highway runs, the bluetooth just goes bonkers and starts fast forwarding the song, cutting the song, pausing randomly, only solution is to disconnect and pair again, it has happened more than once and it intermittently cuts audio no matter the type of phone. I thought it was a phone issue but I don't face such an issue on any other bluetooth device. Seems to work fine when connected through CarPlay. The issue is more pronounced on longer journeys, could be a overheating issue? I have no clue. I have no idea if thats a common issue for other car owners. If it makes an difference I have the L&K edition. Any suggestions as to what I should tell my SA are welcome, thanks guys! Cheers!

[mrgf]

Random guess but bluetooth is a system for sending signals to and from one device to another. A little mike radio, C.B. or mobile (Cell)  phones.

 

As you state it happens on long journeys, I might suggest the bluetooth is struggling to connect efficiently and is mis-reading etc. A bit like a radio statin needing re-tuneing or being out of range.

 

As I say, random guess. You would have thought the tech would be better then that but, hey!

[clutchtime]

1 minute ago, mrgf said:

Random guess but bluetooth is a system for sending signals to and from one device to another. A little mike radio, C.B. or mobile (Cell)  phones.

 

As you state it happens on long journeys, I might suggest the bluetooth is struggling to connect efficiently and is mis-reading etc. A bit like a radio statin needing re-tuneing or being out of range.

 

As I say, random guess. You would have thought the tech would be better then that but, hey!

Hmm, makes me wonder if there was any signal interference but the phone is right next to the dash so I doubt it. Was wondering where the bluetooth module is placed? Is it in the glovebox with the maps unit? or is it embedded into the infotainment unit? I do a lot of computer hardware, could narrow down the issue if I know where it was