If you're considering a w12, do it they're wonderful cars. HOWEVER get ready to open that wallet up.

I have a coolant issue on my w12 (low coolant light, overheated, parked for months before I took it to my shop because I travel quite a bit.

If anyone has any leads on the parts listed in the photos below 07c121086m, and really this whole assembly I would really appreciate that. We haven't pulled the engine yet (my mechanic REALLY, REALLY) doesn't want to if at all possible to maybe partially drop the engine or work another way in there to replace the circled part - it seems the plastic there broke and we're needing to replace. Has anyone seen this done before - is it even possible? Im having issues finding the parts even on diagrams in ELSA-WIN and the Audi parts website so no clue if parts are even out there for this thing any help would b hugely appreciated. I parsed through some posts with Mishar and MP 4.2 + 6.0 commenting in them but didn't quite find the information I was looking for on this particular part. I can't be the only one who's had this fail.

 

Did some looking around and https://www.lllparts.co.uk/product/0...M/coolant-hose shows

07C121086M being the whole assembly but elsewhere shows ONLY the silver part that holds the coolant temperature sender (06A919501A. - 4 in the diagram
4D0261546 This is the check valve (7 in diagram)
The part we are ultimately also looking for is that "Double hose" part but it doesn't seem to be listed on any diagram anywhere despite being clearly a part of the engine lol

 

The LLL Parts diagrams are my current preferred ones, so maybe best you will do. Seems like what you are referring to is only listed as a whole assembly numbered part 1--the hose area directly above where that bracket symbol and the number 1 appears? Correct?

Maybe try the "practical. Go on Ebay and search for "coolant hose Audi W12" or "coolant hose Audi 6.0" [some ads, more so in Europe just put engine size] Set search as worldwide--very important. I have been buying discontinued hoses for weird areas in either Britain or the Baltic states (Estonia, Lithuania, etc.). You'll have to sort through a bunch of hits, but by picture may be able to find it--and perhaps a good price. In one case for a discontinued hose at the heater block, I ultimately had to buy used (in USA) as my only source.

 

The LLL Parts diagrams are my current preferred ones, so maybe best you will do. Seems like what you are referring to is only listed as a whole assembly numbered part 1--the hose area directly above where that bracket symbol and the number 1 appears? Correct?

Maybe try the "practical. Go on Ebay and search for "coolant hose Audi W12" or "coolant hose Audi 6.0" [some ads, more so in Europe just put engine size] Set search as worldwide--very important. I have been buying discontinued hoses for weird areas in either Britain or the Baltic states (Estonia, Lithuania, etc.). You'll have to sort through a bunch of hits, but by picture may be able to find it--and perhaps a good price. In one case for a discontinued hose at the heater block, I ultimately had to buy used (in USA) as my only source. Also, try the part number for the whole assembly. Again, in a worldwide search. And if unsure you are really getting the right results, go on EBay.de (Germany) and eBay.co.uk and type in just part number and Audi, searching at least European Union. If they won't ship to USA or it is vague, any listed will show up there. By any known part # you drill right in and language doesn't (initially) matter, and a lot of Euro parts listings are very fastidious about including part #'s.

 

hi happy to see you on the forms again, perhaps not under the best circumstances but it’s nice to see you’re still around I was able to do some more digging around today. It looks like my mechanic is pretty confident that he can do this hose with the engine in the car, but dropping the transmission. I’m still on the hunt for the parts hopefully I can get them before I fly off to Germany next week, but if not, maybe I just pick them up and bring them home for my baby.

I was able to confirm a couple of things first off part number 07c121086m is indeed the full assembly from Audi however, when people are parting these cars out, they tend to separate that part not realizing that it is all one piece from Audi. They do happen to have one sitting in Sacramento right now that I could order for 900 and some odd dollars. Furthermore I was able to confirm that the part number for the check valve is 4D0 261 546

I’ll be finally getting up from my bed rot day and scouring the bowels of eBay for this part. I did some searches in the states last night similar to how you suggested, but didn’t really come up with anything

also looks like while we have the subframe pulled he wants to replace the front right bag. Is there any reason not to use the Amazon bags if I don’t intend on driving the car a ton? I’m already gonna have a $2000 labor bill on top of whatever parts end up costing me So I’m getting stretched a little bit thin on cash reserves

 

A few subjects and reactions:

1. As you consider what to do, realize taking off the upper intake on top gives you 4-6 inches of reach lower down. Are you familiar with that? Standard procedure now for plugs changes, has to come out for thermostat, injectors, etc. Any W12 owner or mechanic should know how to do it, or needs to learn over life of car. Maybe 2-½ or 3 hours remove and install, once you have done it before. Opens things up a lot. Still super tight in that firewall areas to rear though. For example, I can do the cam sensors and the water temp sensor. Before I posted on the intake technique for the water temp sensor, the common approach was to drop the motor. Not any more. Given area you are after, driver's air box likely comes out. And if that comes out, the driver's fender liner does too (to get at box drain clamp under the box as only way to do it to pull lower box out. Similarly, jobs you need ot know to work on a W12 anyway. Would maybe give some side reach. Looking at pics, presumably hardest thing if motor is in place, will be unclamping and clamping hoses at an accessible point, and undoing/redoing any supports that keep them positioned. Seems like taking more of the whole assembly out and at higher (or lower) clamp points is a likely. The you can replace sections needed that you buy.

2. If you drop things, why not just the motor and tranny assembly together, and only partially in general. (maybe 6 to 9"?) Then you are basically disconnecting anything from there to the body before lowing whole subframe as a cradle--wiring harnesses, hoses, etc. Power steering might be a real TBD, since rack stays with body. You would have to clear anything underneath like the cross brace back by center diff, and probably undo exhaust back at rear joint area. But seems intuitively a lot easier than fighting with exhaust and the header and cat area all crunched in there with the tranny, having to disconnect driveshaft, having to get at torque converter to flywheel bolt up points, etc. Never dropped one though, so just speculating--and having seen underside and reached my hands into that area dozens of times over the years and various jobs, including tranny pan drop ,fluid service and valve body solenoid kit swap out.

3. If by bags you mean the air struts, on last one, I just bought an eBay used one from lowest miles, most recent I could find. Notthat many $ now--at least last I bought one. W12 front is same as non-Sport 4.2, so lots around. I have never disassembled one (some have), and I think chances of getting a lemon rebuilt are as bad or worse than getting a lemon used OE one.

 

For point 1: I am aware that removing the upper part of the intake gives quite some room by comparison but i was unable to replace the cam sensor myself for example (now i mention it maybe he can swap that while there) not sure if I just had bad luck or just not quite equipped to be able to do that. I believe at this point it’s good for me to trust my mechanic to do it correctly. It’s far above my reach, but I was able to help him find the parts eventually through some research Here and other forums, and with the help of Audi as well. I did end up buying the entire assembly from lll In the UK it was half the cost of ordering it from Audi and even other used ones were 300 or 200 USD, also in Europe compared to 400 for a brand new “genuine Audi” assembly and I’d rather just buy brand new if we’re gonna have to drop the engine again to do it in the future instead of just buying the new one now.

As far as point 2: again, this is pretty far above my pay grade here. I just don’t really understand how everything would come apart and go back together. I have a pretty good knowledge of mechanics, but not nearly to the point of something like this car has even using Elsa-WIN to look at diagrams and procedures. Literally step one shows remove engine and neither my mechanic or myself really want that to happen just in case of breakage of other parts in the process unless we absolutely have to. if the transmission is coming out anyway the engine coming out, would not be too far behind if it does need to be pulled.

3: i ordered some amazon ones for now for the front. Can’t quite spring for the arnett ones from FCP euro *yet* but i will order those in the coming months just to have around the house front and rear with a lifetime warranty. May even try to tackle those myself in the future if i can find a nice guide (I’m sure you or mishar have a write up somewhere)