Excessive drooling

My son will be 3 in June. At his 2 year well visit, we had brought up to the pediatrician that we felt the amount of drool he produced was excessive, but she told us once his 2 year molars came in, it would subside. Well that was almost a year ago now, and he still has excessive amounts. I’m talking pouring out of his mouth constantly. The front of his shirt is constantly soaked. He drools more than my 1.5 year old. He did initially have a speech delay, but has since caught up, and he is a thumb sucker, in case any of those facts attribute to the matter. We plan on bringing this up at his 3 year well visit, but I was wondering if anyone has experienced this with their child? And any tools to help?