Hi all looking for advice on a system I've recently been called to!!

Original call out around 1 month ago to a d6 rj 4000 6 cylinder compressor....

Customer complaining of 1 cylinder head very warm and smoking!

On arrival compressor was isolated by them, I ran system up to find the smoking was from the unloader gasket so ordered gasket and plate set as this was worn commission system running all ok...
Yesterday I was recalled by customer complaining of compressor failing on oil switch..

On arrival I checked the obvious,oil level pressure etc I found was all good until the 2 unloaders were activated under load (eliwell step controller) and my oil pressure suddenly dropped and equalised to suction pressure causing it to activate oil switch I just wondered if any1 has had any problems like this....

It's a dual compressor kit serving 1 evaporator and it's a belt chiller chilling cakes

Set point 0
Ambient 7
Suc temp 6
Discharge temp 85
Liquid 35
Oil pressure 81 psi (when on no load)
Suc pressure 52psi
Liquid pressure 215psi

Cheers guys

Danny