Fan acts really weird

[ivanfbi]

My fan starts by itself after I drive like more than 10 minutes, If I drive a lot, when I park my car, fan starts right after I turn the engine off, and works for about an hour, Also, it starts when I drive more then like an hour, and I still can hear the noise of it through the noise of engine and this Is first car I see with this problem. My car is 87 LX-i. I thought it might be the relue in the fuse box. I went to jy and pulled the sam one, but the problem is still there. I have a CAI, and all the small hoses which were going into the air intake, got their own little breathers, except for the vaccuum line, I just locked it. BUT the problem was there when I bought the car, so I don't think the problem is with CAI. HELP PLEASE

[BMS]

if your fan turns on after just 10 min of driving it is possible that there is a broken sensor somewhere that says, "the engine's hot turn on the fan," even though it's not hot.

[ivanfbi]

do you happen to know where that sensor might be?

[rdn]

bottom of the radiator...towards the battery side

[86LXItooFAST4me]

its something with your cooling sys. not any sensors i dont think. our cooling sys is kinda funny, it is a preasurised sys. if you look at your thermostat housing there is a bleeder valve that you can bleed any air out with. if the water is not full all the way or something is rendering the flow (bad thermostat, or no thermostat). i would check the thermo anyway if you havent yet.

[smufguy]

the fans turning on after 10mts is prolly the secondary thermo switch on the thermostat clickin in. HOw is the temp gauge at this point? Does it show normal half way thru? Fans do come on under idling, so if it does not and u see steam come outta your radiator, then u got a bad sensor, the on the bottom of the radiator, this sensor is the primary sensor.

fans turning on after u switch off the car is normal. Cause the fuel injected cars did come with sub cooling relay and module that cools down the engine by having the fans run for about 15 to half hour automatically. But if its an hour then prolly the module is at fault. All u have to do is, go under the passenger seat, pull the big black rectangular box, swap it with another one from the junkyard and see how the fans operate. at the same time, u might wanna swap a sub cooling fan relay (found in the engine bay fuse box, silver cylinderical relay).

IF nothing works, get a new thermostat and check ur Antifreeze and water ratio. the lowest u can go is 40/60 and the highest u can go is 70/30 (antifreeze/water) proportion.

[ivanfbi]

I changed the relay you were talking about. But this is funny, some people say that its good, that it cools down autom. by other don't think its supposed to be like that. And, what rectangular box are you talking about?

[smufguy]

I changed the relay you were talking about. But this is funny, some people say that its good, that it cools down autom. by other don't think its supposed to be like that. And, what rectangular box are you talking about?

like i said in the above post, its the big black rectangular box, it controlls the fan on efi cars. Its the fan timer.

[bobafett]

i would think that the behavior of your fans is NORMAL....

but when your car is off, the fan shouldnt come on for an hour, more like 10-20 min

[adams86lxi]

check to see if its your ect sensor (engine coolent temp. sensor) with my b20a my fan turns on everytime i even start my car for just a sec, since i dont have a spot for the ect sensor to plug into! But if it was that sensor the pgm-fi light would be on so check that out.