I've changed temp sensor as gauge was sitting at 70 and mpg suffering as a result. Now however it's only sitting at 80. Is there anything else that stops it sitting dead on 90??

Oh and when I first changed it I forgot to put the o ring back duuurrr

thermostat not working right? Does it stick at 80 or does it drop if your say on the motorway?

It prob moves to 90 in traffic and drops to 80 when on the move. I'm Confused

Edited 23 December, 200916 yr by the cat

sounds like it could be the thermostat jammed open, that way you too much cooling when driving at speed and so the engine temp goes down. Does it take a long time to warm up from cold?