I have installed a dual electric fan that was laying around my buddies garage to cool my Chevy 502. It pulls real hard and when functioning properly keeps me running at a nice 195 max temp. The problem is that when the car gets hot the fans run intermittently. It'll kick on for a few seconds and then shut down and then kick on again. I am running an aftermarket universal thermostat with a 30 amp relay. It was blowing the 25 watt fuse and I switched it over to a 30 amp circuit breaker and was running fine until it all heats up, and thats when it starts shutting down. The relay gets real hot and I find what seems to be an oily substance around the relay and its mounting block. I don't understand fully how a relay works and I am wondering if the current draw on these fans is higher than 30 amps (that's what the relay is rated at) would it explain this behavior? Should I bum it up to a 40 or 50 amp relay with accompanying rated fuse? Do all single pole double throws work the same way and is any SPDT relay interchangeable within my mounting block? Thanks in advance!