Since you used a presumably good battery (it starts the wagon) I would have to guess the starter isn't spinning fast enough, could be a sign of a dying starter. Also, thicker oil when cold will cause the engine to crank slow. What weight oil are you running?

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.