Zmanco Posted August 28, 2006 Share Posted August 28, 2006 I just installed electric fans on my '73 and used an adjustable kit from Hayden (part #3651). When the engine first warms up, it works as it should and turns on after the engine gets up to temp, and then shuts off. But if I let it idle for a while and get into a steady state, the fan controller starts to continuously turn on and off so much so that the fans don't run at full speed. Eventually it may go to full speed, or it may shut off. The engine never overheats, but I'm suspicious that the relay and fans will have a short life being constantly turned on and off like that. Plus the ammeter is jumping around as well which will only put more stress on the regulator. I had expected this kit, which was $60 (not including fans) to have some hysterisis designed in so that it would turn on and not turn off until the temp had dropped some significant amount, like maybe 5 degrees, so that it would either be on, or off, but not in this fluttering state. I'm wondering if this is a design flaw, or if this unit is just defective. Are any of you using this model from Hayden? (It's the one with a 2 wire sensor that screws into the thermostat housing, not the type that has a sensor that is inserted into the radiator fins). Or are you using another brand/model? BTW, I tried searching but could only come up a suggestion to use a fixed thermo switch from a Cavalier tied to a relay. I had considered that, but liked the idea of an adjustable unit. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted August 28, 2006 Share Posted August 28, 2006 I had the one that inserted into the fins and it was a piece of crap. It was very sensitive to any adjustment made but not as sensitive as it should have been to the actual coolant temp. It finaly just died and I went back to using a toogle switch and watching the gage. I will be going to a preset temp switch that installs into the thermostat housing soon so I don't have to worry about not seeing the temp gage quick enough. All that said I would not by another adjustable temp switch. Dragonfly Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted August 28, 2006 Share Posted August 28, 2006 oops double posted... Dragonfly Quote Link to comment Share on other sites More sharing options...
v80z Posted August 28, 2006 Share Posted August 28, 2006 switch Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted August 28, 2006 Share Posted August 28, 2006 What kind of temerature probe / thermostat are you using for the fans? .. You need to put it somewhere the heat retention/dissipation(SP, Sorry I'm drunk) ..... is better. Slows down the switching of the thermostat/fan control... Or you can build a simple delay circuit.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 28, 2006 Share Posted August 28, 2006 I used a thermoswitch from the lower rad hose of a 240SX. It is set to come on at ~210 degrees and turns off again at ~185. It comes in it's own metal tube that you just splice into the lower rad hose, then I have a relay powering the fan itself which is wired straight to the battery and doesn't have anything to do with the stock harness. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 28, 2006 Author Share Posted August 28, 2006 I used a thermoswitch from the lower rad hose of a 240SX.Jon, I had seen you mention this earlier, and like this idea a lot. I'm guessing that with the probe on the output of the radiator, you get a reasonable amount of hystersis. My problem is a lack of 240SX in the junk yards. There wasn't even 1 last time I went to the pick n pull. I was rumaging through my collection of parts last night and found the thermostat housing from my L28 (from an '80ZX). I'm using the L24 unit but noticed that the L28's has what looks like a thermo switch. I tried it out last night and it looks like it turns on around 185 degrees. But the resistance was about 60 ohms which is a bit high to switch a 30 amp relay. Has anyone tried using this? At least I have the parts:) Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 28, 2006 Author Share Posted August 28, 2006 Just spoke with a tech at Hayden. He says the controller should have 10 degrees of hysterisis and figures mine is bad. Checker has a new one on order. We'll see... Quote Link to comment Share on other sites More sharing options...
heavy85 Posted August 29, 2006 Share Posted August 29, 2006 Jon' date=' I had seen you mention this earlier, and like this idea a lot. I'm guessing that with the probe on the output of the radiator, you get a reasonable amount of hystersis. My problem is a lack of 240SX in the junk yards. There wasn't even 1 last time I went to the pick n pull. I was rumaging through my collection of parts last night and found the thermostat housing from my L28 (from an '80ZX). I'm using the L24 unit but noticed that the L28's has what looks like a thermo switch. I tried it out last night and it looks like it turns on around 185 degrees. But the resistance was about 60 ohms which is a bit high to switch a 30 amp relay. Has anyone tried using this? At least I have the parts:)[/quote'] The L24 and P90 head on the newer L28's t-stat housings dont interchange - at least mine dont ... or at least they didn't as I sold the P90 for $ for the LS1 . Anyway my P79 stat housing doesn't have any extra holes in it and neither does the rest of the engine. We dont have pick and pulls around here so I'm stuck with a switch. I actually used a three position switch so that I can manually turn it on, turn it off, or turn it on auto just there isn't a stat connected to the auto setting yet. I've found if you are moving you never have to turn on the fan. If you are in stop an go traffic have to watch the gauge. I also run it just for peace of mind while idling to the line at the autox then turn it off during the run. Cameron Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted August 29, 2006 Share Posted August 29, 2006 Anyway my P79 stat housing doesn't have any extra holes in it and neither does the rest of the engine. Nothing a drill and a NPT tap won't cure. Quote Link to comment Share on other sites More sharing options...
Alex_V Posted August 29, 2006 Share Posted August 29, 2006 Theres 3-4 240sx's in the local picknpull here. Looks like Im going to pull one some time soon. Any one else want one? ~Alex Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 29, 2006 Author Share Posted August 29, 2006 I should get the replacement controller tonight, but if my problem persists, I'd really appreciate you picking up one for me. I'll PM you if I need one. Thanks for the offer! Quote Link to comment Share on other sites More sharing options...
buZy Posted September 1, 2006 Share Posted September 1, 2006 I just use a direct switch and monitor the temp. Less wires and hastle. Though I have to say that Jons idea does sound like a darn good one indeed. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted September 1, 2006 Author Share Posted September 1, 2006 Update: replaced the module and the new one works as it should. Just my luck to get a bad one... But if I was to do it again, I'd take Jon's approach with the sensor in the lower rad hose. This controller has about 10 degrees of hysterisis, and given it's measuring the temp at the thermostat, the engine temp is going through the 10 degree swing, rather than just the radiator. I suspect that if it was measuring off the rad output, the engine's temp swing would be less. And it would have been cheaper too Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted September 1, 2006 Share Posted September 1, 2006 A switch, we manually power the electric fan on. Quote Link to comment Share on other sites More sharing options...
Guest ZFetsh Posted September 9, 2006 Share Posted September 9, 2006 For me, I'm going to have them (2 radiator fans) running most the time on just a rocker switch, as the engines thermostat will only take enough water to keep the engine temp at its predetermined temperature - as long as the radiator temp is colder than the engine temp, you should be ok Quote Link to comment Share on other sites More sharing options...
sir_daniel Posted September 9, 2006 Share Posted September 9, 2006 i'm using a switch and turns the fan on when i know that that the car will be needing the extra cooling that the fan provides. Quote Link to comment Share on other sites More sharing options...
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