Dear all,

in my 1980 Chevy Van sits a 6 cilinder 250 engine.
When I start the engine there is very much blue/white smoke coming out the exhaust.
The engine then runs very poor.
After some time about 30 sec to 1 min the smoke dissappeares.
Then there is coming exhaustgases with lots off oil coming out of the exhaust.
Also there is a lot off oil on the exhaust/ carb side off the engine.
The cooling water has the right green color.

What can it be?
Cracked head or headgasket gone?
The temp gauge always gives max temp even when it is not so (in my opinion)


Thanks for your advise

greetings from the Netherlands

Frank