GLB35 cylinder head

[Mr.Gheewala]

Hi everyone,
This is the first time I'm posting on a car forum.
I purchased a GLB35 about 3 weeks ago. The car had done 31k miles and a full MB service history.
I really enjoy the car, it's the perfect blend of family practicality and sportiness, for me anyway.
Over the weekend I noticed the car shaking violently and the engine warning light came on.
The car is now at the dealers and I've been told it's the cylinder head issue that is common in the AMG35 engines.
I come from a Toyota/Lexus background so I've never experienced engine issues before. Whilst I really like the GLB35 this incident has left me quite anxious.
Luckily the repair will be under warranty so it's not a problem however I would like to know if after the repair is it likely to happen again? And are there any other issues that I should be aware of?
It hasn't been 30 days since purchasing the car so I could get my money back and get something else, but I'm really struggling to find a car that ticks all the boxes the way the GLB does. Do I stick with the GLB or pull out and get my money back?

Any advice would be much appreciated.

[Benson11]

This is a fairly common issue that affects some 35 series cars with the M260 engine, the misfire is caused by the cause valves/seats burning out.

The replacement cylinder head is a revised part number and to my knowledge repeat occurrences of the issue are rare, so assuming the workshop do a good job of the repair this should be the last you'll hear of the issue.

[Mr.Gheewala]

Thank you so much for the reply. It's reassuring to hear that.

[BEARDYB0Y]

Id echo the above. Ive seen a few cars with this issue but never seen the same car come back twice.

You have an exceptionally rare car right there! Ive only ever driven two. Apparently there are only around 300 in the UK... and under 25 facelift models!!

[Mr.Gheewala]

Thank you so much for replying. I wasn't aware of the rarity so that's great to hear.

[Mr.Gheewala]

So the dealer told me to 'not give it full power' for the next 4k miles as the new cylinder head needs to be worked in.  I only do about 2k miles a year!
Has anyone else with a new cyclinder head been told the same?

[BEARDYB0Y]

All AMG models have a recomended running in process to follow. This normally consists of keeping the car under 3k RPM, avoiding gear kickdown and driving softly for the first 1k miles. Then after that the recomendation is to slowly build RPM and harder driving for the next 3-5k miles.

As you have a brand new, shiny engine part installed it will need running in again.

Id say its a good excuse to drive it more in the coming months... but I was in the exact same position with my A45, it took me 18 months to run it in!

[Mr.Gheewala]

Krikey, I've already taken it to around 5k rpm and done a couple of manual downshifts. I'll be sure to take it easy from now on though.

On the other hand, I'm looking for trips to make so that I can build up the mileage.

[BEARDYB0Y]

The manufacturers will always be slightly overcautious when creating these schedules... Im just an overcautious individual!

None of the demonstrators given to dealers will ever follow that run in procedure as customers will want to get the full experiance within a few miles. Its unlikely they will ever get the oil warmed through before being ragged as well!

[Tony1963]

I wonder how many thrashed ex-demo cars then go on to fail at 30k miles…

What a crappy situation. And another that’s costing Mercedes a fortune in warranty claims.