If it's lower end I'd be surprised if it has lived a life with adequate oil change and proper oil level maint. Lower end may signal the end of the engine. Did this come on all of a sudden? I have seen upper end issues arise as the result of a busted exhaust valve spring causing the piston to smack the valve and bend it...shaaazaam. Total compression loss. Pulled the head, did a valve job with new springs. Problem solved. It was on a comparably formidable blue oval mill-the famed 3.0 2v iron duke of the Ford flavor.

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Thanks,
Mark in NC

"Spark plugs?...We don't need no stinking spark plugs!"
1985 300SD "Der Silberne Schlitten" 420,000 mi


Wish these were diesel:
2003 Ford Club Wagon 130,000 mi