Heater not working after SR swap

[InfamousSilvia]

I have a 95 240SX with redtop SR swap, I did the swap last year, and after it was done, my heater has not worked since. It worked fine before. I did not run the A/C compressor or any a/c on the SR swap, I didnt think this had anything to do with it. Please if anyone has had this problem or can give me a clue what might be wrong, please let me know asap!

Again, Heater worked fine before SR swap, and now will not work????

Thanks,Brian

[180fan]

lines prob got reversed.

[InfamousSilvia]

Hey man, I have had that thought in my mind since day one! The 2 heater hoses behind engine that go into firewall is what your talking about, correct?

My instincts been tellin me thats what it is, but I figured it could still work, well I guess Ill be fightin with heater hose lines tonight!

Thanks,Brian

[Henry G]

Yeah, sounds lines you don't have it install right. Heard it's a ***** to do it after you've installed the motor. Good luck.. keep us updated.

[travisn]

you need first make sure you have the right hose going to the right fitting. it will still work, but it wont be as efficient. the most important thing is to make sure you have the heater temp control all the way on hot. 240's have a hot water control valve that will shut off coolant flow to the heater core when in the cold position for better cooling. if it is on cold the air pocket from having the lines off will be stuck in the radiator and will not allow coolant to go through the heater core. you may have a hot running car also, but not guaranteed...

[spider_slayer]

have you bleed the coolant system? air in your coolant system will result in the heater blowing cool air.

[driftin'180]

i had the same problem with my sr and it was an air bubble this was about a week after the swap tho i would think that an air bubble would work its way out , not sure but just a thought

[95lstegman]

mine also blows cold air. Koyo radiator but stock thermostat so it still runs at whatever ~190*F. between the middle line and the one below on the stock temperature sensor. never goes over. EVER. but even when warm it blows cold. i was thinking maybe it had to do with the overly large radiator, so the thermostat may not be opening all the way up even when it's fully warmed up. i'll check and see which hose goes to which port on the firewall.

[mallbor240SR]

i have the same problem with my swap, but i fugured it out, one of the heater hoses was kinked right by the firewall, im using the heater hoses that heavy trottle sells for the swap, i tried to fix it but sometimes the heater only works when i rev the engine, so the pressure of the coolant is good enaugh to pass thru that hose then my heater starts working fine once the water pressure builts

[Silverbullet91]

Since your heater worked fine before the swap it is most likely that you got your heater hoses crossed. You wouldn't be the first person to do this so don't feel bad if you did. If I'm not mistaken this is only a problem on s14's. I don't think it matters which way they go on an s13. My heater works fine in my sr swapped s13.

[95lstegman]

it doesn't work on my S13. but i bought the car not running, so i wouldn't know if it's unrelated. it's FL, and not winter yet. i'm not that bugged. and it makes enough HP to offset the 5lbs of jacket i'll have to wear when it gets cold, anyways.