I just changed my oil cooler on my 98 12v due to oil getting in my cooling system i put a used cooler in. Also noticed that my engine oil was way down is it possilbe that the cooler is NFG? and still leaking by idle it runs 20-30 psi oil pressure. Running down the high way no load 120 kms runs about 70ish? Also over heats and oil pressure sending unit bounches off zero. And its been about a week since i changed it.