signum intermittent blue smoke and weird temp gauge

[kevsmit]

hi ive a signum 1.9cdti 55plate
the mileage is 100.000
but recently its been smoking on and off so i took it to the garage and he says yeah mate i've put a new egr valve on and a new set of glow plugs i thought sound so i drove back from the garage took me 1 hour no probs
however today same problem but i've noticed that the temp gauge drops from 85 to 0 then and only then it starts smoking
and i also found out that if i turn it off and restart it stops smoking and temp gauge goes back up to normal how odd is that but it only has this problem when driving it can be sat ticking over and also being rev for an eternity and no smoke no temp dropping nothing please help

[Big Dave]

hi ive a signum 1.9cdti 55plate

You need to post in the appropriate part of the forum. This one is Insignia troubleshooting.