Posted by Lenny D. on December 16, 2004 at 19:19:12 from from 68.11.56.27
In Reply to: Thermo Valve. . .? what does it do. . posted by Jaime Obando on December 16, 2004 at 12:07:38:
As explained to me it is/was a 'limiting' device by not allowing full vacuum advance to the distributor when the engine is cold in an effort to reduce 'wear'.
When operating temperature is reached the valve 'pops' open allowing air (manifold vacuum) to pass.
Your enhanced performance during warmup is perhaps at the risk of premature engine wear!
HTH
'80 528i