hellllp

Hello new to this and was wondering if anyone can help me. ive got this old bmw 316i and ive got a overheating problem . i can tell you ive had a new head gaskit new water pump and new radiator. the head has been pressure tested and ive taken out the thermastat . in the hope it will solve the problem but no joy. the strange thing is when i have the interia heating on the temp stays about have way.The bottom hose is stone cold but the top hose is hot. tried squeezing both hosese exspecting them to be rock hard only to find there not. any ideas im at a loss.
i will be gratefull for any pointers
thanks.
nick.

Defective or incorrect radiator cap is either preventing pressure from building up or is allowing a partial vacuum to develop in the system.....

Or a kinked or collapsed radiator hose.