I bypassed the cooler to test still no OP. I have steel braided lines with AN fittings. while it is first started I crack the fitting loose at the front cover and get OP. This only happens when it is sitting overnight. It always has good pressure after the initial problem.I am using the racing beat high pressure rear regulator and shimmed the stock front regulator with 2 washers. I am using 10 w 40 oil. Any help would be appreciated, thanks