I have a Zenith automatic door closer which is squeaking. On initial installation it never squeaked.

I have it nicely adjusted to close the toilet door so the tongue/latch justs sits against the strike plate of the door frame. But every time we open the door the spring or what every squeaks quite loudly (amplified by the door many fold). We have lessened off the tension but then the door does not close fully. Now this is just a stock standard internal honey comb door and well within the manufactures spec's, not all that heavy.

Is there away to oil or graphite powder this mechanism?