Because you’ve already logged the problem with your dealer, it should be on file as a pre-existing condition. Now that it has become worse, you need to take it back to the dealer and have it checked again. If the dealer won’t look at it for you, you need to do two things. First, have the vehicle independently assessed by a transmission specialist. Secondly, you should take the matter to Hyundai’s Australian customer service division.

The symptoms you’ve described are consistent with problems far too commonly found in dual-clutch transmissions. Shuddering and slow gear selection are far from unknown in this make and model, and Hyundai even had a software update to try to alleviate these problems. At the very least, the dealer could try the new software, but if left unchecked you could end up with a dead transmission that could cost many thousands to replace. So it’s crucial to keep the dealer and Hyundai Australia in the loop to maintain your warranty cover.

It sounds very much like there’s a blow-by problem with this engine. The pressure created by the combustion process is somehow getting past the pistons and into the crankcase, causing the dipstick to leave its tube and blowing oil all around the engine bay.

Blow-by is often caused by worn or broken piston rings or a damaged piston itself. But modern turbo-diesels are also prone to problems with their crankcase ventilation and emissions-control systems which can become full of gunk and not allow the crankcase to breathe properly. At which point, the same symptoms can occur.

A mechanic will be able to do some tests and determine what’s causing the pressure build-up inside the crankcase. If it’s internal wear, a rebuild may be required. But if it’s a build-up of crud inside the emissions-control systems, a manual disassembly and clean might be required. Either way, your car’s warranty might cover you for this, so the Hyundai dealer is your first port of call.