Engine Mount Bolts Anti-Seize Warning

[audifan]

Something just was not sitting right with me regarding the torque settings for these bolts..

Here is the manual page just down from your illustration and gives a table with the following torques..

Component	Nm​
Bolts/nuts	M6​	9​
M7​	15
M8​	20
M10​	40
M12​	65​
Except for the following:
Battery plus (+) cable to starter	16
Earth wire to gearbox	22
Bracket for wiring harness to coolant hose/pipe connection	10
Drive shaft heat shield to cylinder block	33
Air pipe to:	Turbocharger	8
Sump	8
Body	8
Engine cover panel to bracket	5.5

M10 bolts are 40Nm and no mention of plus "X" degrees


The same torque is also mentioned in the table higher up on that page. Where did you find the torque of 60Nm plus 90 degrees?

Information from this page...

Audi Workshop Service and Repair Manuals > A2 > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine assy,cylinder block,crankcase | Installing engine

A2 > Audi Workshop Service and Repair Manuals > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine assy,cylinder block,crankcase | Installing engine

workshop-manuals.com

 

[Indi]

Something just was not sitting right with me regarding the torque settings for these bolts..

Here is the manual page just down from your illustration and gives a table with the following torques..

Component	Nm​
Bolts/nuts	M6​	9​
M7​	15
M8​	20
M10​	40
M12​	65​
Except for the following:
Battery plus (+) cable to starter	16
Earth wire to gearbox	22
Bracket for wiring harness to coolant hose/pipe connection	10
Drive shaft heat shield to cylinder block	33
Air pipe to:	Turbocharger	8
Sump	8
Body	8
Engine cover panel to bracket	5.5

M10 bolts are 40Nm and no mention of plus "X" degrees


The same torque is also mentioned in the table higher up on that page. Where did you find the torque of 60Nm plus 90 degrees?

Information from this page...

Audi Workshop Service and Repair Manuals > A2 > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine assy,cylinder block,crankcase | Installing engine

A2 > Audi Workshop Service and Repair Manuals > Power unit | 3-cylinder TDI unit injector engine (1.4 ltr. 2-valve), mechanics | Engine assy,cylinder block,crankcase | Installing engine

workshop-manuals.com

Audi Workshop Service and Repair Manuals > A2 > Power unit | 4-cylinder direct injection engine (1.6 ltr. 4-valve), mechanics | Engine assy,cylinder block,crankcase | Assembly mountings | Assembly mountings - exploded view

A2 > Audi Workshop Service and Repair Manuals > Power unit | 4-cylinder direct injection engine (1.6 ltr. 4-valve), mechanics | Engine assy,cylinder block,crankcase | Assembly mountings | Assembly mountings - exploded view

workshop-manuals.com

Bolts number 8 here, its the same for the other engines too I think

 

[PlasticMac]

The plus X degree thing is, I thought, only for stretch bolts?
All other fixings are correct at the stated torque. I'd think that even a couple of degrees past the specified torque figure, on a non stretch fixing will over torque by a significant margin. If it's a steel male into an ally female, the female thread has to give, as the male won't.
Mac.

 

[Little Dog]

Just done an experiment, I tightened a M10 * 1.5 screw to 10Nm + 90 degrees then measured the final torque. It felt far tighter than I would tighten a screw working by feel with a breaker.
The final torque was 60 Nm so + 90 degrees = + 50 Nm
The torque specified in the manual 60 Nm + 90 degrees would result in a final torque of 110 Nm which is outside the specification of a M10 10.9 grade bolt. Either the bolt or female thread would most likely fail.
It has been pointed out that Audi recommend a torque of 40 Nm for other M10 bolts. It feels sensible to apply the same torque to these three engine mount bolts. I repeated my experiment this time tightening the bolt as I would with a breaker. I then measured the torque. 40 Nm. I'm comfortable with 40 Nm to secure these screws.

@PlasticMac plus X degrees is essential for stretch bolts but can be applied to any bolt. It causes lots of confusion and good to reuse 10.9 fasteners go in the scrap bin because they are assumed to be stretch bolts

 

[audifan]

Still want to know where you read the torque for those bolts was 60Nm plus 90 degrees as the manual page I listed does indeed show 40Nm only. for the M10 bolts.

 

[Little Dog]

Still want to know where you read the torque for those bolts was 60Nm plus 90 degrees as the manual page I listed does indeed show 40Nm only. for the M10 bolts.

The torque specified for screw 1 looks too high too:

Anybody doing this repair please read this thread in full before torquing these fasteners

 

[Little Dog]

A tip for @Indi , when you coil your threads the 5mm deep clearance hole above the thread plays havoc with fitting the coil. The top thread on the coil does not insert as it should increasing the pitch of the first two threads. I had to use a much smaller coil application tool so the stop ring would fit down the clearance and hold down the top thread of the coil so it inserted correctly.

 

[Little Dog]

Are they blind holes? Years ago I was warned about greasing things into blind holes as it can create a hydraulic lock causing this kind of issue?

Yes they are blind holes but they are deep blind holes. To get the hydraulic lock problem you would have to pump a grease gun in there. A small amount smeared on the thread will not cause hydraulic lock problems.