Noob with 2.0 TFSI engine questions

[Johnny5C]

Hi all, new to the Audi experience having just collected a 2007 convertible 2.0 TFSI. First impressions are... I love it... what a well put together car.

It has 130k miles on the clock with full service history in the book. It didn't have any other receipts or paperwork, but it starts, runs and goes really well. MOT history wasn't anything to worry about. 

But, just one niggle. The engine is loud under load in second gear, from 1300-1800 rpm. the noise is virtually un detectable if I drive like a granny, but the slightest bit more right foot and there is the noise. Is a metallic high pitched rattle but not in the heat shield sense. Plus, if im down shifting into second gear, and the rpms are in that range, when I hit the bite point and the revs go up, there is the noise again for a fraction of a second while the engine speed matches the transmission. Im convinced I can also feel it through the clutch pedal. 

I didn't pick it up on the test drive, because I was being a bit lead footed to give the car a good workout.  When you get up through the gears quickly, the time spent in the "noisy band" is very small.

My intuition is telling me its transmission related, but I have never had a Turbo before, so it could be something to do with that, or the diverter valve? (but is it really at boost at such low, and increasing RPM's?)

I have googled the hell out of it, but none of the noises I have listened to on youtube sound like mine. Like I say it's only under load, in that specific RPM band so I can't replicate it on the driveway. Google takes me to engine mounts, diverter valve, DMF, etc..

The other thing to note (just in case its related) is the temp gauge is variable between 12oclock-ish and 10 o'clock ish. I haven't been able to determine any repeatable logic with driving conditions yet. 

I have just put in a new air filter. 

Any thoughts would be appreciated.

I'm so tempted to take it to Audi because they would definitely be able to hear it, and the car is under warranty from where I bought it, so best to check it now!

 

[Magnet]

Hello John,

Many thanks for being in touch. 
‘Metallic high pitched rattle’ :- It is always very difficult/ impossible? , to diagnose such issues without test driving and examining the car, so unfortunately you boil down guesses, like timing chain ( if chain driven) and/or a result of the timing being advanced enough to cause the engine to pink under load. 

‘...felt through the clutch pedal...’ guessing again - possibly DMF issues would tie in with this. 

Variable coolant temperature? My first port of call would be defective thermostat. 
 

Right, having said all that, you should not have to be concerned with the causes, but certainly concerned about their rectification, and you should be informing the seller (in writing) of what the issues are.

Taking it to an Audi dealer? I certainly wouldn’t, without the consent and agreement of the seller, otherwise they could rightly claim that a third party had been interfering with the car. 

To me, time would be of the essence in terms of notifying the seller - I would be doing this as a matter of urgency, rather than Googling the symptoms to death! 
Perhaps you could let us know how you get on. 
Kind regards,

Gareth. 
 

[Johnny5C]

Thanks Gareth. The used car dealer is over 2 hours away, so I wanted to see if I could get an idea of the issue before I got in touch. I still don't know if it is an issue or just a feature of the 2.0 TFSI engine.

I was hoping someone here might know these engines well and could give me some pointers. I can do a replacement diverter valve myself, but i can't do a clutch and DMF.

The audi dealer might be able to pinpoint it quickly, that is all, with just a quick drive. 

The noise is annoying, but the otherwise the car is without fault.

Oh, BTW the 2.0 TFSI has a toothed belt for timing.

On the other issue, should the coolant temp stay the same and not deviate?

[Magnet]

Hello John, 

Thanks for the additional information. 
No criticism intended, but it’s yet another case of the disadvantages of buying any vehicle (ex internet search?) and the comparative impracticalities for any offered warranty. The theory is that the seller must be allowed to correct any faults, and the warranty may (in caps) dictate that faults found within period x of the sale date, must be financed by the seller. 
Some (many?) warranties allow the buyer to get the car repaired at a garage of their choice, but it’s not uncommon for  garages to not want to be involved due to the potential wait for payment. Anyway, and hour with the small print will tell you where you stand. 
In my experience, noises are not characteristic of a model. The car is trying to tell you something. 
Possible clutch issues? Carefully check your warranty for any ‘wear and tear’ exclusions. 
Temperature gauge fluctuations? Not normal and quite likely to be what I said. 
 

Your call John, but if it were me, I would still be following my earlier advice regarding notifying the seller. You can specifically ask that you get the car inspected at your local Audi dealer, but again, I would get that done with the minimum of delay if they agree. 
Kind regards,

Gareth. 

[Sammyrai]

Hi,

I have same car and engine and almost same age. 

To diagnose the thromostat, if you are stuck in traffic, does it stay at 12 o'clock, and if you start driving say, above 50mph for 10 mins, does it go down to 10 o'clock?

If so, the thromostat needs replacing. I did mine two weeks ago and now it stays on 12 o'clock all the time 

Also, check your oil level on these engines, they can burn 1 litre of oil for every ~600 miles (as stated in the manual).

I do not have a high pitched noise in 2nd gear btw.

 

[Ianswebb]

Does the service history make any mention of the gearbox oil being changed? My initial thought was the clutch release/thrust bearing, but would expect to hear that a majority of the time the clutch is dropped. 

Ian

[Johnny5C]

Thanks for the replies. 

Just to follow up, I haven't driven the car much lately, and have just tolerated the noise. (Its a soft top, and the weather hasn't been compliant)

Today I took a 1hr journey on the motorway, in the sun and it was lovely. 

Tonight I decided to take the kids out for a short drive and I noticed that the car was quiet through the acceleration band I mentioned above. 

I was thinking maybe the noise is less apparent when the car is cold, but that's the thing.....

For about 30 mins of gentle driving, the temp gauge never went above 70. (Halfway marker between 50 and 90)

All the time it was there, the car seemed quiet.  The original noise wasn't so "in your face". 

I'm thinking the stat is stuck open, and has been failing to operate properly for a while. 

But, what would this have to do with a noise while under load? 

Water pump?

Car is 130k, FSH. (Due an oil change now)

I have looked at the thermostat DIY guides, and I could probably do it myself. But if anyone here has any intuition, I'd appreciate the logic check!

[Johnny5C]

Another follow up. I just did the thermostat and cam follower.  Now I know the engine temp, it's easier to think about this 2nd gear noise. 

My intuition is that it's transmission related. It just seems too loud under load in 2nd up to 2k rpm. It's worse when cold (I think).

I will probably change the gearbox oil as its not that tough to do. But my underlying feeling is that the gearbox is knackered.  

I know these TFSI engines are noisey, and it could be the fuel system i suppose, putting more fuel in when the load comes on? 

What else gets stressed under load?

At least I have eliminated the cam follower. 

(On edit, it's due and oil change, but it's not low on oil now.)

Edited August 28, 2021 by Johnny5C

[Magnet]

Thanks for coming back on this John.

We take it it’s a manual gearbox. You mention changing the gearbox oil - daft question, but does this box actually have a drain plug? If not, you will have to resort to sucking the oil out.
If it does indeed have a drain plug, make sure you can undo the filler plug before opening the drain plug. Rather serious when you’ve drained the oil off, and find the filler plug doesn’t want to be undone! 
Kind regards,

Gareth. 

[Johnny5C]

Hi Gareth, thanks for your reply. It is indeed a 6 speed manual, and from the DIY guides I have seen there is a drain and fill plug.

I will definitely be taking the fill out before attempting the drain. This is good advice.

This noise is bugging me. If its normal then this is way too loud for a modern engine/transmission. 

It makes me cringe because such a good looking modern car shouldn't be making these noises, and I'm sure pedestrians can hear it. 

Perhaps I will never know the source. 

It's like when in second, and the engine is "behind" the accelerator position I makes a noise. If I back off the accelerator and the load drops, the sound goes away. 

It doesn't do it "bogging down" in any other gear. Perhaps a little in 3rd, but nothing like in 2nd, and probably only because I'm listening for it. 

[Johnny5C]

Just a quick follow up after some time trying to identify the sound. I recently did the HPFP CAM follower, and replaced the faulty thermostat. 

The noise is still there, and now I have had a chance to start and run the car plenty of times I think I have a repeatable issue. 

If I start the car from cold, and let it idle for a few minutes until the revs drop, there is no sound, but if I start and drive away immediately, the "under load" noise is present. 

Weird I know, but i have done this a few times now, and its repeatable. 

Amd guidance would be appreciated. 

(2.0tfsi b7, manual. )