AAN and ADU engine numbers and locations

[UrS4boy]

The AAN engine manual and Bentley both say that the engine serial number is located at the back of the block, exhaust side. I have never found anything there (YMMV).



There is also supposed to be a number on the block, perhaps under the intake manifold. This way you could check to see if you have a "numbers matching" engine and head pair (if anybody cared). I couldn't find either for my 93 S4.

Then I was given an ADU Engine No. diagram, which suggested that the engine number is on the head, just under the front cam cover breather nipple.



Using that diagram, I was able to find my engine number on the head (still haven't found the one on the block). Here is one AAN example, in this case, 010965 (a March 93 built AAN):



The engine number also shows up on the sticker on the cam belt cover, as pointed out by 2doubled's photo (in this case 019008):



Presumably ABY engine numbers are in the same location as the ADU (and AAN)

Here are the ADU engine number build dates:



Here are some AAN engine build dates:











Thanks to those who posted the diagrams and photos used in this post.

[Majorcina]

So AAN engine number is on the head?If so i am in trouble since mine is from 7A

[K Simmonds]

I've always found them in that location, including on 3B's, never managed to find any on a turbo block.

[Majorcina]

Just to update this,i checked to see engine number from the engine i removed from my s4,and only number is on the head,nothing on the block(on the spot which Dave showed)

[UrS4boy]

Just to update this,i checked to see engine number from the engine i removed from my s4,and only number is on the head,nothing on the block(on the spot which Dave showed)

Yeh, I should remove that factory diagram. Complete bovine excrement. I never found it on my spare engine either.