It would be wise for you to find another garage. There is a screen inside the oil pan usually on the oil pickup to keep large particles from entering the pickup but as far as an oil filter, I have never seen or heard of an engine that did not have an oil filter. I once had a 331 hemi from a 1955 Desoto and it had an oil filter. If you have a 4 cylinder engine look on the side of the engine either in the front or back and you should find the filter.