Left my quik detailer in the Z on a hot day, when i returned to my car at the end of the day, it was leaking and the bottle swelled up and look like this now? WTF?

 

That happened to me also. Expect it did it to both my Quick Detailer and Interior Cleaner. I thought they mentioned in there ad that you can keep it in your car for those special times were you need it.

 

any plastic bottle left out on a hot summer day will most likely do that. Ever seen what happens to an unopened coke can? They heat up and since they are closed there is no place for the gases that are built up to escape to.

I have one in my spare tire well at all times, never had that problem

Call meguiars, they may take it back, they have great customer service.

 

physics.

temperature goes up = pressure goes up
temperature goes down = pressure goes down

 

maybe it is the content of the bottle or the type of plastic used. I kept a bottle of simple green in my Z and it retained it's shape.

 

in the sun...not in the sun...volume of product in the container, etc, etc...physics and common sense...hot car + liquid...at least you didn't leave the kid/dog in the car too