I wouldn't be too concerned with the engine oil leak if it's minor because it's quite typical for these old turbodiesels to seep a little. The rear leak around the driveshaft is more alarming to me but that alone shouldn't put you off either if you're willing to put some money into it. I'd be most concerned about the rust which can be very expensive if not impossible to fix depending on how advanced it is. Check underneath the floor mats to see how the sheetmetal is doing.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL