I just bought a 95 neon 5spd highline. The car was not heating properly so I did a flush n' fill(70%water/30%antifreeze), replaced the thermostat, and changed the radiator cap. I have good pressure in the system, but still not blowing hot air. The cooling fan kicks on when I turn on the defroster and runs for a few seconds, then turns off for a few seconds, then back on. It keeps doing this as long as I have the defroster on. Is this normal to turn on and off continuously like that? The temp guage never gets more than about 1/4 of the way off "C". If I unplug the cooling fan then the defroster blows hot, but the car eventually overheats. Could someone have installed a fan relay or temp sensor that makes the fan turn on and off continuously or is this normal for neons.

 

try a larger type thermostat? i have never heard of this problem before. does it blow warm on a low setting of the fan? cause mine blows hot when on low and cool when on high. also check the relay under the hood for the fan, it may need relacing, but that wont cure the cool air problem.

 

The reason the radiator fan is cycling is the ac compressor cycles when you use the defroster. I would check to see if your heater core is flowing good. There are two hoses going through the fire wall on the passenger's side. Warm the car up with the heat on and touch each hose. Both should be warm and about the same temp. If one is cooler your heater core is clogged. You can run a garden hose through to try to clean it out. If you can't get a good flow through then you are gonna need a new heater core.

 

I know the a/c cycles when you use the defroster but, I've never noticed one cycling every five seconds. Isn't that accessive? I checked the heater core hoses and both seem about the same temp. The lower might be a little cooler but, not much. Could the water pump be shot? I don't see any antifreeze leaking anywhere, but I don't what else it could be. Maybe I'll blow out the heater core anyway. Does it matter which hose I blow into, top or bottom, and could I use air instead of water(I put the water hose up for the winter)?

 

If the water pump was bad the car would be overheating or leaking fluid. You could use air, but you are not going to be able to see if its flowing. They should both be the exact same temp, its only a very small radiator that its going through. I would think that you are only getting a small flow throught the core. Flush it good or replace it.