BlueWagon

Could you just monitor oil temp on the dash display and back off a bit when it goes over say 140C.

Maybe...but what are you going to do about it? Probably wait until it either dies or starts really making a song. Id just be aware of it and monitor it. My Landcruiser one makes a fiar noise and I know its gonna die some day....but probably just let it run on until it stops working

Sounds like the noise of the AC compressor working. If it cools fine and the noise isn't that loud under the bonnet, Id probably just go on living my life and let the compressor work away as it should. My suggestion would be to have someone cycle the AC while you listen under the bonnet if you are really worried, but other than tinkering with the AC compressor its probably a leave it alone kind of thing

Why? Can they not use degreaser and a hose? Id do the same if I were you. Just wash engine bay with spray degreaser and water at car wash close to garage. No need for steam clean

Does it make the sound with engine turned off. Might be easier to answer if we can hear it with the engine turned off

Personally Id just go to the dealer and get a genuine one. In Aus they are about $35....which isn't too bad for something made in Europe and you know isn't cheap Chinese junk. Or, local auto parts store and get the recommended Ryco or Mann filter. They will have a book with all the applications

Did you check coolant etc after overheating? Maybe water in the combustion chambers. I can't see how a water pump could cause a misfire and stall. No way. If it jambed it would just snap the belt. Im thinking an electrical issue there. Bad earth....

Id say that's a common thing with DSGs, they can't always anticipate your conditions so yeah, occasionally it gets it wrong. No biggie

My Mk3 with 7 speed dsg does this if I shift into D or R to quickly after starting. As in less than 1 second after start. I suspect it is just me beating the computer's start up sequence. I dont think its a big problem. Solution: start, wait say 2 sec, maybe put seatbelt on, then engage gear and drive off.

Maybe a grub screw that locks into those recesses on the shiney bit of the new one, so at right angles to the main body

Looks like the case. You may need to replace the hose to the bottom of the close up picture

Id suspect the master cylinder is at fault? Was it an aftermarket ebay special?? I have seen aftermarket calipers and cylinders do similar thing on Toyota's in the past. Jambed brakes. That said, why did you replace master cylinder? Maybe that is the underlying cause??

Really depends on how it started. If it was suddenly then maybe yes, do get it looked at sooner. If it was a gradual thing (likely and you only recently noticed it) its probably not a massive deal. Id certainly be checking trans and diff oils ASAP though. Sounds alot like a worn diff bit do get back with the answers to the questions about the nature of the noise

Describe the whine in more detail. Does it happen in every gear or is it engine speed related? Does it come and go if you take your foot off the accelerator and coast? What about during engine or foot braking? As suggested try turning the wheels a bit while its happening? Does the noise change?

Degraded battery or poor terminal connection Id sort that before doing the diagnostic work Might clear alot of the faults

Fair. Probably best to let the mechanic do it. Wouldn't you just let the mechanic buy what they need? That's how it normally works right? You don't buy anything if you aren't doing the job. Just take car to mechanic and they will get what they need based on their experience.

I reckon after 5 minutes Id have turned the engine off....if not just to save fuel and exhaust stink. Water pump or pump drive belt failure Thermostat failure These seem most likely and probably easy to check with a bit of fiddling.

CAT? Flexible coupling? Flange? muffler? DPF? Turbo??? I dunno man, maybe post a photo man, then we can have a look and a better guess man

Maybe just old oil from small leak burning off a now much hotter engine. Id suggest not stopping engine if turbo is hot. Make sure you keep it running for a bit for turbo to cool down before cutting off the oil supply.

Also, make sure your car is level when you check the oil. My block is sloping and it's a PITA to accurately check oil levels.

This is what I'd keep doing. Maybe need to try startingwith a fine screwdriver to open up gap and get the larger screwdriver and then chisel in. Need to spin and insert chisel at same time. Sometimes a ring spanner can be used to pull a bit if you pull it off square a bit. Eg pull the free end outwards quite alot. Try pulling and working bolt back and fourth at the same time. Or, if you can get a welder, weld a link of chain onto the bolt head and pull on that.

My Octavia did this once or twice i just turned key off and restarted. Seemed fine after that. Software glitch Maybe just needs a hard reset. So discount the battery for a while.

Is the relay clicking on and off while fan turning on and off? Id be thinking false reading of temp somewhere

Check this. But would probably run with ignition off if this were the case. Really need a wiring diagram to see where the power to call the fan for does come from. Maybe ecu??

Do you mean the radiator fan? Id think that and the oil pressure switch are unrelated.... Suggest looking at temp sensors for the fan fault. Maybe faulty ecu Maybe stuck fan relay Need more details. Eg does the fan cone on as soon as you turn the key on, or to start, or is the ac on (that will make fan run)