Smitty5534

There has to be a way I know more then one person have replaced the coolant pipe on a D3... Please Help
Hi I'm trying to remove those exhaust studs to move coolant pipe up to clear oil cooler. I'm not having any luck. I tried to lock two nuts together and then remove them with a deep well but they don't loxk together the just spin off together. What am I doing wrong? Thanks in advance

richard-tx

Apply some heat to the manifold with a small acetylene torch. Get the manifold red hot and the stud will come out.

Take a look at this video of Audi testing an engine. Note the manifold color.

richard-tx

One more thing to remember is how fasteners work. It isn't just torque that makes them stay put, it is molecular bonding. Remember that familiar crack that occurs when loosening fasteners that are tight and have been in place for a while? What you are hearing is the molecular bond breaking loose. Over time, the molecules of a properly tightened fastener will migrate from bolt to nut and vice versa. This self locking feature only occurs over time. The longer the fastener sits torqued, the more molecules migrate and the stronger the molecular bond.

Get a torque wrench, two new nuts, torque the nuts to within 5% of maximum and let it sit for a couple of hours. Then try to remove the stud by turning only the nut furthest from the end of the stud. If that does not work, add heat. Don't heat the stud. Heat the exhaust manifold and don't be afraid to get it bright red either. Heat expands the metal and that expansion will break the molecular bond making it easier to remove the stud.

mishar

I would strongly advise against torching anything in that area. You can easily damage something, even set your car on fire. Besides that, studs are screwed into the cylinder head not into the manifold. So heating manifold won't help.

MP4.2+6.0

I have not had to deal with the oil cooler issue on a 4.2, but I have removed many an exhaust stud on Audis--nightmares back to the C1. The two nut method mentioned is the tried and true way. Get different nuts w/ same threads if it helps fit them or get a better wrench grip, especially w the lip/self washering newer Audi nuts often have. Heating manifold makes no sense to me--besides the fire risk it is logically just expanding the metal mass that the stud is bolting down in combo with the nut and thus increasing tension on stud. If anything I would think you would want to freeze it.

I haven't done the job, but recall posts about the stud being the real b%$#$ to solve. Search for prior posters and ways they did it. I think there have been a couple of how to's that folks came up with along the way. Board members turn over every few years, so people who did it before may have "left the building" and wouldn't see this thread now.

richard-tx

Sorry, My bad, I thought you were trying to get the stud out of the manifold. Since it is in the head, do NOT attempt to apply heat. Heating aluminum is tricky business. It goes from a solid to a liquid without warning. All else applies however.

I have found it is sometimes helpful to use a 3/8" impact on things like studs or bolts that are in very tight. The impacting action has a tendency to move parts that would normally just twist off if just straight torque was applied.

jamm220

I had this same problem and this what I did. I just did the job in December and I was just as frustrated until I took a break and start thinking.....


I use the two nut method as well, but the nut at the top I use a grinder and trim up the edges so that the deep socket can fit over it so that its only grabbing the actual nut that's holding the manifold. Trust me it works like a charm and pretty simple.

ill also give you another trick to getting the housing off with more room. Remove the end part of the sub frame that the impact absorbers go into. I think they are about 5 or 6 bolts, it will allow you to look directly at the housing with nothing in front of it. See the attached pic with the red park marked. hope this helps

Smitty5534

Thanks everyone for the replys. Jamm220 I used a two 13mm nuts with the outside nut grinded way down that no point on nut would grab the deep well and put it stung tight against the inside nut and when I try to loosen them they both come off together ugh! I didn't see too many nuts at hardware store with those treads that with 10mm size is why I was using 13mm nuts. I'm a smart guy it can't be that hard lol but I'm not doing something right

mishar

I don't think so. Those studs are there for a long time. Some Galvanic corrosion between two different metals and temperature almost fused them in. That's the main reason I skipped that replacement and went with stop leak. It may not be too late.

P.S. You may try Loctite red. Apply it to those two nuts tight them together and let it stay for some time (they say 10 minutes but a bit longer won't hurt). They promise it won't come of without heating. You can heat it once out of car.

jamm220

Give me a call I'll walk you through it 404 542 9524