Hi just recently got a 1991 honda civic hatchback and noticed blue smoke coming from exhaust when started and when shifting what could be causing this ?

HI thermostat gauge is not working in my 1991 honda civic I believe thermostat was recently changed is there a sensor somewhere not working?

Worn valve seals or valve guides. The rings would be bad, if you saw blue smoke almost all the time.

Head gaket was recently changed is it easy to fix warn valve seals or rings can I do this myself

Just received a answer to my question about blue smoke thank you now do you recommend me fixing this myself if so how hard is this and is car still driveable have to drive it 6 hours one way and back this weekend do you recommend this?

Rings, no. Valve seals, possibly. It will require some specialized tools. Too bad the valve seals weren't done while the head was off.

You should be able to drive it--it will just smoke. Plugs will really get fouled and it will pollute. To pass emissions testing, it will obviously need to be fixed.