Heater core

[Andym]

Does anyone know where I can buy a heater core for my 1985 C4 and does anyone else suffer from over heating causing their C4 to stall in traffic

 

[Steven Smith]

Does anyone know where I can buy a heater core for my 1985 C4 and does anyone else suffer from over heating causing their C4 to stall in traffic

RockAuto, £50 delivered or Eurovetts.
Have you got the TPI engine?

 

[Chevrolet]

I remember replacing the heater core on my '85 (TPI) many years ago. Are your passenger side carpets wet?

1) Have you got a Haynes manual for the car that has the fault problems/likely causes listed in it? Can probably find those on the internet now?
2) Have you checked if the car has any fault codes? Can use the bent paper clip trick in the ODB (?) port below the steering the wheel to identify those.
3) At what temperature are the cooling fans coming on? As per factory spec? Maybe (just) a Thermostat problem?

I'm not a mechanic, but hope that helps?

 

[Roscobbc]

I replaced the heater core on my '68 perhaps 20 years ago. Surprisingly Summit racing had it in stock and at a price way less than other source. Don't know if this is competitive and what carriage/shipping/duty will cost.

 

[Andym]

I done a temporary loop on the pipes èleminating the heater core problem ut now the doesn't co e at the rad I done paper clip test and the fan works .I was told it could be the temperature switch sensor on right side near dip stick Does anyone know if that's correct

 

[Andym]

Fan *

 

[Steven Smith]

I done a temporary loop on the pipes èleminating the heater core problem ut now the doesn't co e at the rad I done paper clip test and the fan works .I was told it could be the temperature switch sensor on right side near dip stick Does anyone know if that's correct

The fan is controlled by a switched negative supply given out from the ECM.
This is from an AI search:
Main Fan / Auxiliary Fan Switch: Screwed into the rear of the passenger-side cylinder head (between cylinders 6 and 8). It acts as a thermal switch that grounds the relay to turn the fan on at high temps (factory spec is around 238°F).
If it's a single wire switch grounding the wire should switch the fan on, if it does that proves the switch is faulty.
I have fitted a separate fan controller on my 86 and set it to switch the fan on at 190°.(Adjustable Fan Controller Thermostat)
You can also change the activation temp in the EPROM if you have the correct hardware.
If you want to fit the separate one as above I can give you a guide how to fit it.
A slightly lower thermostat also helps keep temperatures down but don't go too low.

 

[Andym]

That would be great , thank you

 

[Steven Smith]

Fit controller here.

Put temperature probe into top radiator hose her
This is the fan wiring diagram (assuming the same as my 86)
If you get the same temperature controller that I did then it doesn't need a positive supply to work.
This is the wiring diagram for it.
Wire Pin 2 to ground and Pin C to pin B on the fan control relay.
Wiring it like this has several advantages, if your original fan works correctly it will still come on at 225°F should the aftermarket one fail preventing overheating and the AC switch will still control the fan through the ECM without issues.