Common Engine
Oil leaks from rear main seal
Symptoms
Oil weeps or pours from the back of the engine, usually visible around the bellhousing. Can soak the clutch on manual cars.
Cause
The B18 and B20 rear main seals are old-school rope-type or early lip seals that harden and fail with age. Heat cycling and sitting for long periods accelerates this.
Fix
Pull the gearbox (or engine, your choice of hell).
Replace the seal.
It's not an expensive part, but it's a full weekend job.
Use genuine Volvo or quality aftermarket seals, cheap ones leak within months.
While you're in there, replace the clutch if it's oily.
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