D13 egr problems

I been having problems with this truck for the last 2 months so I take it to the dealer they replaced my egr cooler and egr valve get on the road the following week same problem so volvo replaced it a week later same problem now it’s back at the shop and they said it’s the egr cooler and egr valve again they did a further investigation and the found nothing.... has anybody else had this problem or know what it could be because I’m ready to do the do with this egr and say f it my truck got 603033 miles it’s a 2013 Volvo D13

 

Spn 94 fmi 18

Spn 1127 fmi 10

Spn 1127 fmi 14

Spn 1127 fmi 18

 

Ok

 

Yeah they just called and said they found a airbubble in my coolant system but idk if that’s when they just replaced it or from the first time they did it

 

They found A air bubble in my coolant tank i don’t know if that was because they just replaced the egr cooler or the air bubble was in my lines when they just replaced it