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I have to replace 2 of those aluminum nuts with steel Bolts for top oil sump, some of them snapped up when torqued to 8Nm. Don't mention to 90 degree's turn.
Last edited by jasonfire; Oct 29, 2024 at 05:24 PM.
There is a reason why Audi uses it on its products
Stainless steel and aluminum can create galvanic corrosion when in contact with each other
If you are screwing stainless bolts into aluminum threads, you will likely experience galling, where the stainless cold-welds to the aluminum. You must use something like nickel anti-seize to prevent this
Stainless steel bolts have different torque specifications than aluminum. Be sure to follow the proper torque values to avoid stripping the aluminum threads
I did think about buying stainless bolts, but the second thoughs and your reminder to change to normal high tension steel bolts
maybe just some galvanized bolts.
There is a product called Tefgel that is used in the marine industry to prevent corrosion between stainless and aluminum, it may work with mild steel as well.
For the standard grade it has a max working temperature of 260 C. They may have a higher temperature grade.
There is a reason why Audi uses it on its products
Stainless steel and aluminum can create galvanic corrosion when in contact with each other
If you are screwing stainless bolts into aluminum threads, you will likely experience galling, where the stainless cold-welds to the aluminum. You must use something like nickel anti-seize to prevent this
Stainless steel bolts have different torque specifications than aluminum. Be sure to follow the proper torque values to avoid stripping the aluminum threads
It's holding top oil pan to the engine block, so I would not worry about it too much, it is into the cast iron. Of course I would not torque too much. Same 8Nm plus half required turn should be enough.
There is a product called Tefgel that is used in the marine industry to prevent corrosion between stainless and aluminum, it may work with mild steel as well.
For the standard grade it has a max working temperature of 260 C. They may have a higher temperature grade.
Bolts, not nuts. Bolts have the threaded shaft, nuts thread onto the threaded shaft.
Not aware of any of the bolts being aluminum except the "can only be reused once" bolts holding the transmission to the engine. Audi certainly uses steel bolts with the aluminum wheel bearing housings. Ask anyone in salt states who has had to deal with the pinch bolt or the rear damper bolt (not me, those come out easy living here).
But I guess bolts that are "never reuse" marked might be aluminum, such as the transmission pan bolts, etc.
For the Gen2 2.0T (specific engine is not identified), the upper oil pan to block bolts are 2x M8x85 long ones and then 11x M8x20 short ones. The short ones are N91048802. But those short ones are triple square heads, not allen or torx. https://audi.oempartsonline.com/oem-...bolt-n91048802
Interestingly, the M8 bolts for the oil pan are marked "replace if removed", while the three M6 bolts for the baffle are not marked as such. The torque spec for the three M6 is 9 Nm.
If this is actually a Gen3 engine, anything could be different, so none of the above should be taken as relevant. (I believe you started off with a B8.0 3.2L V6, but now it's a B8.5 2.0T? But unsure if Gen2 or Gen3 engine in it).
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AU: Why Audi used son many aluminum bolts?
