Trevor M

If it is the slave cylinder leaking I would imagine the fluid level is likely to be falling. The master cylinder can leak fluid past the seals and back into the reservoir, and under these conditions the fluid level will remain constant. This could give a clue as to where the problem lies. Good luck in resolving it.

Probably best to check for error codes before doing anything else. Poke and hope is best avoided.

If the local garage serviced the Haldex and / or diff. and then the same garage confirmed there was little/ insufficient oil in the diff., it is clear where the blame lies I would have thought. You may have made a mistake in not returning to the garage immediately you noticed the noise in any case. It is probable you could have avoided too much damage; continuing to use it is also likely to mean there is a cost to you because of the resulting damage. Sorry if this sounds a bit harsh (it is not meant to,) you have my sympathies. PS: If the local garage only changed the coupling (and did not work on the Haldex / diff.) immediately before the noise started, it may be the new coupling and / or fitting of same is at fault and the low diff. oil is a coincidence.

I have to say, I think the video above was the most informative home made one of its type I have seen. I started watching out of curiosity, for a quick browse, rather than having any current need for the information, but found I became 'hooked' by the excellent presentation and finished up watching most of it. Informative, amusing and entertaining - what more could one want ? Thanks Vimal-Jith for posting this and also thanks to the guy who produced the video from wheelsandmotors.com.

I have only used them for the supply of a new mk4 pump plus oil and filter. Have to say their service was excellent; I have heard others say the same thing.

Not quite the same vehicle, and not sure if it applies here, but some VW group vehicles have a bag of silicon (I think) within the coolant header tank to prevent corrosion. These have been known to fail with the silicon 'grit' escaping and blocking the heater matrix. My Grandson has an Audi A3 TDI (2013,) which suffered this problem. Others have replaced the heater matrix to overcome the problem, but in his case it was fixed by removing the hoses and reverse flushing the heater matrix directly from a mains water pressure hose (I understand it needed repeat flushing in both directions to completely clear it,) then replacing the header tank. On the Audi, replacing the matrix would have been an awkward time consuming job - the same probably applies to the Yeti. Hope you succeed with it.

My 2013 170 Yeti is still on its original Varta battery, although for the last four years the voltage when tested before starting in the morning has been around 12.1 Volts. I also had the battery tested by a Skoda main agent when it was in for a service four years ago, expecting them to say a new one was needed; however, like yours, they said it was ok. on a load test. I assume it is one cell which is not up to scratch, and have been expecting it to fail each winter since, but it has not failed to start the car once, even on frosty mornings (it is parked outside.) I suppose having said that, I should now expect it to fail shortly ! On the tickover, mine runs at 850 rpm when warmed up, but during the winter this will take longer, and 1,000 rpm is seen more often (also when 'doing a regen'.)