CHT in a Cherokee-235

[Aviationteam]

I am running a 1963 Cherokee-235 in Germany.
Lycoming has 350 hrs and runs with Phillips XC 60/Camguard.
Since last annual in Sept 2014 with a Cylinder Inspection due to a work order I face 390-410 F during climb at Cyl 2, whereas all other Cyl are working at 350-370 F.
Just did 50 h-inspection without any findings.
Has anybody an idea, what could be the reason and what to do?
Could this be a result of changing the oil system from synthetic Aeroshell to mineral Phillips??

Thanks for any comments!

Georg

 

[skywag]

 

[flyguydon]

 

[Gary235]

 

[Orest @ CYFD]

 

[Orest @ CYFD]

 

[Gary235]

 

[Aviationteam]