[Lucky Dog 33]

Agree with above. The IR gun is a great way to track down a problem. You can use it to follow the flow and see where the temps start to rise. Also could be a bad thermostat that may be getting stuck closed at idle. I know it’s new but wouldn’t be the first time I’ve heard a new t-stat was bad. It should be 170deg.

I always start from the source. When was the last tome your pick up scuppers were inspected and cleaned. They can easily clog up with gunk and debris or bottom paint for that matter. Could be not enough flow at low rpm but as pump spins faster becomes enough.

Also on the fwc side, when was last time you flushed coolant? Could have a pin hole somewhere causing air to get trapped. You will need to burp the system to get all the air out.

Good luck