My prelude is running hot I installed a new aftermarket gauge today so I can get a better reading, the fans are coming on late, they come on at 250F everytime, the fan switches are new the relay I don't think is bad just the timing is off, Any ideas???

 

Are you getting voltage to the temp sensor? If you are, try a new temp sensor. While at the store go ahead and pick up a new thermostat as well. They're only like $6-10.

 

The temp sensor is new, and thermostat is new too, haven't checked voltage but they do work just not at the right temp they should, they only turn on at 250F

 

at 250 degrees engine damage can occur!!! When your over heating issue starts happening check to see if the upper AND lower hose are both hot. Your lower hose typically is slightly cooler than the top hose. If your temp gauge is reading anything above 190~ check to see if the lower hose is hot, IF NOT, the thermostat is stuck closed, a new thermostat doesn't mean it is working properly, I commercially sell auto parts in bulk and i see defects everyday. PM me if you need more assistance


I would drain the radiator and remove the lower hose from the radiator and fill with water to ensure the radiator is flowing sufficiently and not blocked up.

 

possible bubble in the hose?

take the rad cap off and run the car for 5min. watch if any bubbles come out

 

Do a radiator flush, and replace thermostat. Parts come broken new all the time so doesnt matter if new or not.... sad but nothing we can do about it, thats why companies have warranties. After you fill your radiator up let idle for about 5 min or so, even reving the engine slightly wouldnt hurt.

cool tip, Just before you put the cap on hold at higher rpm and the engine will suck coolant down. Top off while still holding throttle by hand, and replace cap, let off throttle. There should be no air left and the surge from letting off the throttle should push any remaining air into the overfill along with maybe i tiny bit of coolant.

 

Allright so I took it to my mechanic and he checked the temperature of the upper and lower hoses he said car is running between 184-200p, so the problem is the the guage it seems, Allright so the new guage I put is a jdm sport it was like $30, I installed it like this; I tapped into ignition switch and ground wires from where my radio is connected and ran the sensor wire to the sending unit then spliced the wire to connect my stock one also so I can have both, the new one doesn't read right I turned it on in the morning and it starts at 130F the stock one reads perfect now, I went ahead and cut the sensor wire of the new one before the spliced part just in case I wanted to reinstall again and the stock guage started reading wrong again, What do I do now????