2eighTZ4me Posted July 27, 2009 Share Posted July 27, 2009 I've got a fan relay that kicks the fan on at a certain temp. Problem is, the sensor is a 3/8"NPT size. I've used up the one large bung in my thermostat housing for my temp gauge. Would it be a "bad idea" to port this fan switch sensor at the back of the head? The car doesn't have heat and I've plugged off the rear head outlet and the corresponding front water neck return. Those are the only places available that would be large enough to stick in the sensor without having to go "custom". I'm thinking the front cover might not be such a good location, as water from the radiator that has just been cooled flows through there - might not give an accurate temp reading for the coolant overall - but maybe the rear water port on the head would? Quote Link to comment Share on other sites More sharing options...
thrustnut Posted July 27, 2009 Share Posted July 27, 2009 I'm pretty sure you want the coolent at it's hottest point when you sense it, so the back of the head might not be bad. My fan has an electric saber type sensor that the kit wanted installed just under the radiator return hose in the radiator fins. Quote Link to comment Share on other sites More sharing options...
MAG58 Posted July 27, 2009 Share Posted July 27, 2009 I'd actually think this would be an intelligent idea. The back two cylinders run hot anyways (especially #5) so in reality it would be turning on when the back cylinders got hot. Makes sense to me. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 28, 2009 Author Share Posted July 28, 2009 That's my line of logic as well. As it so turns out, the bung adapter for the sensor fits perfectly in the outlet at the back of the head, so I think we've found a solution. Thanks for the replies guys! Anyone else think this is a bad idea - please speak up now or forever hold your peas...... Quote Link to comment Share on other sites More sharing options...
Rustyfriend Posted July 28, 2009 Share Posted July 28, 2009 I was also hooking up a fan yesterday, and the head seemed like a good idea up until you went to park the car. What I finally realized was that the engine itself takes almost forever to cool down. I waited nearly half an hour and the fan was still running, so off I went and it is now mounted on the radiator. Commentary? Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 28, 2009 Author Share Posted July 28, 2009 I have a switch in the cockpit such that I can disable the fan completely (or can leave it running after shutdown if I choose) I think that will alleviate the issue that you're seeing. Different situation - but yes - I certainly see your point. I'd have a hard time with my gut poking a hole in a $550 radiator.... Quote Link to comment Share on other sites More sharing options...
Rustyfriend Posted July 28, 2009 Share Posted July 28, 2009 Oh, it is an aftermarket radiator with no fins or tabs to mount on? I am still using a stocker, but she should be swapped out soon. Quote Link to comment Share on other sites More sharing options...
2eighTZ4me Posted July 28, 2009 Author Share Posted July 28, 2009 It's a Ron Davis unit with side tanks that I couldn't bring myself to poke a hole in for fear of screwing it up. The mounting bung fits perfectly in the back of the head, so I'm just going to roll with that for the time being and keep a wary eye on temps and when the fan kicks on. Quote Link to comment Share on other sites More sharing options...
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