Extended warranty attempts

[ori]

So I hope you guys like/hate this story as much as I do.
BMW x5 going away with the family somewhere in the country when suddenly the car starts making a racket and the goes pop and stops. No warning lights or messages. Just went pop.

They have extended warranty and bmw assist so get towed to garage. Engine went pop and literally parts went flying through the block. New engine required.

So days later he gets a call and they have reached a conclusion into what caused the engine to blow and why it’s not covered……..now I could stop the post here and see what you guys come up with, but here is what they said.

Car had a mixture of winter and summer tyres and that put extra strain on the engine which made it go boom. Hence not covered under warranty.

There is a happy ending as it was argued and bmw accepted it and are fitting a new engine, but to even suggest that is shocking no?

Can anyone give me the logic of the winter/summer tyre causing this?

[Chippie]

My son has a 3 series touring xdrive and recently fitted none star rated tyres and is now getting a slight jerkiness in the drive train/chassis under certain conditions, apparently the xdrive is very sensitive to different tyre circumstances, so perhaps that’s where the were coming from saying it’s placed extra strain on the engine?

[B21]

My son has a 3 series touring xdrive and recently fitted none star rated tyres and is now getting a slight jerkiness in the drive train/chassis under certain conditions, apparently the xdrive is very sensitive to different tyre circumstances, so perhaps that’s where the were coming from saying it’s placed extra strain on the engine?

Plus one on this…

Some folks say you can mix tyres ‘ rolling radius on XDrive but when I looked at the 4 series XDrive there were plenty of horror stories on XDrive with mismatched tyres..

Quite how that blows the engine rather than the transfer box I’m not so sure about..

[ori]

My son has a 3 series touring xdrive and recently fitted none star rated tyres and is now getting a slight jerkiness in the drive train/chassis under certain conditions, apparently the xdrive is very sensitive to different tyre circumstances, so perhaps that’s where the were coming from saying it’s placed extra strain on the engine?

Plus one on this…

Some folks say you can mix tyres ‘ rolling radius on XDrive but when I looked at the 4 series XDrive there were plenty of horror stories on XDrive with mismatched tyres..

Quite how that blows the engine rather than the transfer box I’m not so sure about..

Spot on. Mix tyres will cause handling issues usually in xdrive systems due to sensor and rotation errors. How you can stretch that to catastrophic engine failure is beyond me.
As you say. Drivetrain…..maybe……still a stretch.