Can't be more specific without more info, but the 2 most common problems in an engine with that many miles are lifters & bearings.
The lifters require a certain amount of oil-pressure to operate properly and if the pressure drops for any reason, they'll "collapse" & "rattle like a bucket of bolts". Normally an oil/filter change, using a high quality, heavy grade oil, @ least 20W50, will take care of that. Personally I use a straight-weight 50 in an engine with that many miles.
If it's not lifters, then it could be either a "spun" bearing or the "death rattle". The 1st caused by lack of oil between a bearing & a moving part like the crankshaft. The part can "sieze" the bearing & spin it right around - no fix for that other than rebuilding the engine.
The 2nd is usually heard when the oil level is too low and/or too thin of an oil is used. As the miles rack up, the clearance between moving parts & the bearings that support them increases & without a good, thick coating of oil to be the "cushion", the part rattles around inside the bearing. Heavier opil can keep the engine going for a while longer, but sooner or later it will have to be rebuilt.
Friday, September 18th, 2009 AT 1:50 PM