oil screen

mad: :mad: :mad: i have a 2000 caravan with 60,000 miles i have changed the oil reguarly 2500 to 3000 miles but recently after start up i lose oil pressure in upper half of engine and lifters start to rattle for app. 1 to 4 minutes does not do it againg tell next morning. i pulled the oil pan found oil screen clogged up really bad with a hard like crust substance I had to soke it over night in gas, put every thing back together i changed the oil at app 3000 miles no more proublems for app 5,000 mile, then it done the same thing again . same proublem found screen stopped up no much build up at all found in pan, just the screen clouged i meen you can cut it off with a knife like beef jurky also another shop in town said they have foud this in to other 3.0 liter dodges after app 50,000 miles i have changed oil brands weights and everything even tried a mopor filter (thats what the dodge house told me the proublem was no luck) please any ideas.