My mk3 1.05 has been running at about 75 degrees for about the last 2 months.

Just replaced thermostat (80 degree rating)

Replaced blue and black sensor units from a gt at the local scrappy

Still never gets above 80 except when idling after a run out then it goes to where it's supposed to (about 90 degrees) but as soon as I get going again it drops right down to about 75.

my questions are

1. Are the thermostats on polo's supposed to have a gasket as mine just has an o ring

2. Does it matter that I took the scrapyard sensors from a g40 when I have a 1.05 AAU (they look identical)

3. Will it do my engine any harm to keep running it at this temp.

Cheers for any advice...............

Well if its an 80 degree rated thermostat doesnt that mean its fully open at 80 so will keep engine at 80 or below?

Doesn't sound like anything to worry about IMO.

cheers for replies.

Yeah thats what I though about the thermostat rating. If its rated at 80 degrees then the car should run at 80 degrees but on this forum most people's temp sits right in the middle of the gauge at about 90.

Just checked the rating stamped into the thermostat and its actually 78 degrees. The Haynes book says that the thermostat should open at 87 degrees but this is the correct part for my model and the previous thermostat was the original VW one and that was rated for 80 degrees so must be ok.

Cant see any harm in running engine at 78 degrees so just gonna leave it.

my 1.0 will NEVER go over 75 unless i'm sat in traffic for AGES!!