Hi guys! My contractor just installed a brandnew Kohler undermount porcelain kitche sink, after few days we noticed about 5-6 hairline cracks that started to collect stains. You can feel it when you run your fingernail on it. We noticed the cracks after installing our quartz counter top. It's under warranty but my problem is removing the whole thing again with the possibility of damaging the countertop, labor expenses etc. question, are the hairline cracks going to chip down the road? Is it going to be bigger and maybe leak in the future? Can it be repaired? How? Hope to hear from the experts. I appreciate it! I'm new to this site and still figuring out how to upload pictures so you'll can have a better understanding of it.

Have your contractor remove it and return it for a new one.....
Best Wishes

I assume this is a cast iron sink. If so, water will get into the cracks and cause the cast iron to rust,and when it rusts it will build up pressure and "pop" the porcelain. Replace the sink.

1 800 4KOHLER... call them and plead your case. if it is defective and didn't show up until after it was installed, you might get labor allowance to replace it.