Hello all: Thanks to everyone who replied to my call for help...
My SO's 85 camper had a very loud tapping noise from the engine.... I
discovered that it was the #4 ex valve lifter not pumping up.....Last
night add a can of "Motor Flush" to the oil after running engine until
hot..... idled for 5 mins and the drained.... let drip for over 1 hour..
changed filter and added new oil... ran at idle for 15 mins..... drained
again, changed filter.... filled crankcase with new oil and fired up
engine..... "Ta dah!" lifter pumped up no more noise and the engine is
running smooth again....
I'm glad I don't have to tear into the engine to replace a lifter.....
Peace be with you,
Doc