I had my van fixed after being hit. When I took it to the shop it was working fine. When I drove off the oil light came on and making a loud ticking noise. I went to a gas station purchased oil. Gas attendant stated it did not need oil it might be a clogged oil filter or oil pump going out. I left work and no oil light no ticking noise. My husband did a complete oil change and oil filter. My 2000 Nissan Quest van has 140,000 miles on it. Can you suggest anything I can do to prevent engine problems. I called the Nissan dealer about a valve adjustment, was told there is no valve adjustment.