Whirlpool ice maker problem

Hi

Whirlpool American side by side model number S20DRSB33A/G

In October last year I had a problem with the ice shute getting blocked with ice and frost. I paid £70ish and the engineer came and had a look. He said that the flap at he the bottom of the ice shute was not closing properly, so ambient air was getting in to the ice shute, melting the ice and causing the problem. He refitted the damper to the flap, and the problem improved significantly. However, I still get frost building up inside the shute, and when I use the ice dispenser, I get a load of frost mixed in with the ice. I am not convinced the engineer really got to the bottom of the problem last October. He saw a fault, fixed it, and assumed that he had found the problem. Unfortunatly Whirlpool won’t come out again unless I pay another £70, so I thought I would try here first.

Any advice gratefully received.

Thanks