RS4 AZR engine rear main seal

[belms4]

As I start setting up for work on an RS4 AZR engine for my avant build I'm coming up with some interesting questions around parts that are interchangeable with the S4 2.7T engines. Currently I'm looking at a new rear main seal with the flange. I was surprised when I saw the parts diagram I have shows the rear main seal with flange part for the B5 RS4 is 06C103171A. This looks to match part number for the B6/C5 3.0L v6. If this is correct, then are both the flange and crank seal from the S4 2.7T incompatible with the AZR/ASJ engine?

I reached out to 034 Motorsport because I have their newer billet rear main seal for the 2.7T sitting around spare and was hoping to use that on my AZR engine. However, that only is built to match the S4 2.7T and part 078103171L. Their techs said they cannot confirm if this would fit an AZR engine.

So what's the answer here? Are both the flange and seal different on the AZR engines and I cannot use either from the 034 kit I have? Or maybe just one of the two parts different? Those who have replaced the rms on an RS4 engine, did you use the 3.0L parts? Thank you!

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[PwrWgn]

I know for sure that rs seal assy is different. But honestly, having bought two different oem seals for an s4 in the last couple years... the factory seal part number is clearly printed on there and i don't see why you wouldn't just press the old one out and a new one in. I'm super jealous of the asj/AZR but this is one of those things that makes it just so impractical, esp stateside.

[belms4]

I know for sure that rs seal assy is different. But honestly, having bought two different oem seals for an s4 in the last couple years... the factory seal part number is clearly printed on there and i don't see why you wouldn't just press the old one out and a new one in. I'm super jealous of the asj/AZR but this is one of those things that makes it just so impractical, esp stateside.

Yeah honestly may not even touch it if I don't find anything leaking and this billet rms isn't going to fit. Maybe just the seal like you said. I haven't pulled things off yet to take a look and will hopefully get to that this weekend.

I hear ya on the parts situation, it's not for everyone, but comes with the territory. Basically nothing has been easy on this build, so sourcing a few more engine parts isn't a big deal to me. Just need to know what I need well enough ahead of time if anything needs to come from overseas. Probably lucked out in that department if this just turns out to be a 3.0L crank seal I can get easily here.

Update: Found on THE-Tuner website they sell different options for s4 and rs4 crankshaft oil seals on gearbox side. Along with what pwrwgn said about the flange being different that seems to pretty much confirm s4 and rs4 rms is different and the 034 billet rms will not fit the rs4 engine. I'll update this thread with some pics when I take mine apart for others to see how different.

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[PwrWgn]

So I fired up ETKA just for fun, and you're right that RMS is 06C103171A which common to the 3.0 V6 engine. Funny they would use that same flange across those engines, but also nice to know the commonality will keep inventory moving (and hopefully stocked!) on these types of parts.

[Silverex]

So a 3.0 and AZR seal is the same but are the actual flanges the same also?

[Blazius]

Here is another hint:

The 3 letters at the start of the part numbers, refers to the application it was first used/developed for, in this case 06C is the block code for the 3.0V6.

[belms4]

So a 3.0 and AZR seal is the same but are the actual flanges the same also?

I think so. It was news to me, that's why I was having a hard time believing I'd found the correct part #. I'm removing the clutch & flywheel today from this engine so I'll be able to say for sure in a bit here.

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[belms4]

Alright, got this taken apart and able to view some part numbers directly on the parts themselves. So....

The flange is part 06C103173A

And it's super tiny and hard to read but I believe this seal itself says 078103051A

So the flange I can't find that part number anywhere. This looks exactly like the 3.0L flange that's part 06C103171A. I checked against pics on ECS website.

The seal seems to match a 2.5L Jetta/Golf V part. Says 105mm on that part number which would match the OD I measured on the seal in front of me. However, 078103051A has been replaced by 070103051A. And this part seems to be a cross reference of 06C103171A.

So in the end, I'm pretty certain the seal is the 06C103171A and it's just use across many different platforms as other part numbers. The flange I'm also pretty certain is this 3.0L flange, and guessing the part number showing on mine is likely replaced by 06C103171A since that's what etka shows.

One minor update:
Found specs on the seals. S4 2.7T seal is 105x85x11mm (at least on the seal included with my 034 billet rms). RS4 2.7T seal is 105x85x12mm.
20230507_122121.jpg20230507_122126.jpg20230507_123431.jpg

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[PwrWgn]

Good info for when i win the lottery and buy an AZR :D

Interesting to see the turbo oil feed is cast into the block rather than the strange external pipe that the normal S4 uses. Definitely a purpose designed and built block!

[ss4]

Yeah, the rear main seal plate is completely different between AZR and APB/BEL. The actual round seal should be the same since I believe the cranks are identical. Would be awesome if you take more pictures of the block internally as well. The upper oil pan is different for sure.

[belms4]

Yeah, the rear main seal plate is completely different between AZR and APB/BEL. The actual round seal should be the same since I believe the cranks are identical. Would be awesome if you take more pictures of the block internally as well. The upper oil pan is different for sure.

I would bet the same seal would fit but from specs I found the rs4/3.0 seal was like 1mm deeper. Otherwise same.

I'm not tearing into the internals of the azr beyond taking the lower oil pan cover off. I can take any pics of the rest of the block anyone is interested in though. There's been some odd discoveries so far. One was there appears to be no coolant drain bolt/plug for the block. I took out the same bolt that would be that plug on the apb 2.7t and it turned out to just be a regular bolt and no coolant behind it. Still haven't found any drain for the block and I'm not sure there is one.

Upper oil pan is different for sure. Shaped pretty different in many areas. I feel like there's even more crap loaded onto the SAI than the auto APBs, which was also interesting. Like a vacuum line running from that to I think the intake airbox to operate that butterfly valve on the rs4 box. At least I think that's where that went to, I can't be sure cause the intake wasn't hooked up when I got the engine.

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[PwrWgn]

Thats interesting, I checked and the AZR service guide just says to drain coolant from the lowest oil cooler hose with no reference to a drain plug.

And yea that extra hose is for a solenoid operated valve (N335) in the lower airbox - pretty trick setup. There is a description of how it works in the RS4 self-study guide.

[belms4]

Thats interesting, I checked and the AZR service guide just says to drain coolant from the lowest oil cooler hose with no reference to a drain plug.

And yea that extra hose is for a solenoid operated valve (N335) in the lower airbox - pretty trick setup. There is a description of how it works in the RS4 self-study guide.

Nice to have confirmation on those, thanks. I am deleting the SAI setup, so hopefully that line to the intake can just T off from another vacuum line from the intake manifold. I tried researching that a ways back and remember it being tough to find info on.

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[PwrWgn]

Sorry I should have written that a bit differently: The airbox valve is actuated by vacuum, but the vacuum is controlled by a solenoid (N335) somewhere else on the engine. I've never seen it personally before but I assume it looks like an N75 or something and is probably mounted near all the SAI stuff.

[belms4]

Sorry I should have written that a bit differently: The airbox valve is actuated by vacuum, but the vacuum is controlled by a solenoid (N335) somewhere else on the engine. I've never seen it personally before but I assume it looks like an N75 or something and is probably mounted near all the SAI stuff.

Ahh I know exactly what you're talking about. Was a little box with plug mounted right under the egt boxes at back of intake mani. I'll have to re-examine this. Think it had lines to the SAI as well.

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[RMode]

Ahh I know exactly what you're talking about. Was a little box with plug mounted right under the egt boxes at back of intake mani. I'll have to re-examine this. Think it had lines to the SAI as well.

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just revisiting this, that same valved airbox setup is used in the C5 S6 as well. I actually deleted it on my airbox setup now. It essentially opens at higher rpm to reduce pressure in the box.

[belms4]

just revisiting this, that same valved airbox setup is used in the C5 S6 as well. I actually deleted it on my airbox setup now. It essentially opens at higher rpm to reduce pressure in the box.

Curious how you deleted it to open at high rpms? I was likely going to get rid of the solenoid controlled part but not sure what to do with the butterfly valve. Remove it? Leave it not hooked up?

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[RMode]

Mines open all the time, I simply deleted the valve completely

I don’t see it being any different to drilling holes in the bottom of the box. It all works the same way, it’s just relieving pressure which bumps cfm


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