1979 425 cu in heater hose relocation

[NickD]

Hi group. I have a couple of questions. Any input would be greatly appreciated.

Can someone tell me which diameter heater hose the 3/4 in. or the 5/8 in. hose is the pressure hose and which one is the suction hose?  The 5/8 inch hose goes to the heater control valve and then to the back of the cylinder head and the ¾ inch hose goes to the top of the radiator.

Is it possible to relocate the current heater hose connection from the back of the passenger’s side cylinder head to another location?  And, if so do you guys have any suggestions as to where.  I was thinking of using a T hose connector (part CHP-CS08) from Cadillac High Performance.

Nick

["Cadillac Kid" Greg Surfas 15364]

Nick
Is the motor FI or carb and are you using all the sensors mounted on the motor?
Greg Surfas

[NickD]

Hi Greg

It is the carb engine.

No. I am using the heat riser port for my aftermarket temperature gauge sender. I have removed the original temperature sensor and blocked off the port.

["Cadillac Kid" Greg Surfas 15364]

Nick,
IF you are not using your EFE sensor located on the passenger side of the motor just under the water outlet that is a usable port into the water jacket. There are four versions of emissions controls for this motor and depending upon which you have the EFE sensor is or isn't used for other functions. The Federal, Carbuerated version does not use this for anything other than the EFE.
Greg Surfas

[NickD]

Hi Greg. I am using the EFE port for my aftermarket temperature gauge sending unit.  I was unable to use the regular temperature sending port because the new temperature sender is to long and hits the timing case cover. What about using a T hose connector (part CHP-CS08) from Cadillac High Performance.

Can you tell me which diameter heater hose the 3/4 in. or the 5/8 in. hose is the pressure hose and which one is the suction hose?  The 5/8 inch hose goes to the heater control valve and then to the back of the cylinder head and the ¾ inch hose goes to the top of the radiator.

Thanks.

["Cadillac Kid" Greg Surfas 15364]

Nick,
The standard sizes are: 5/8" from the motor to the heater valve , 3/4 inches from the heater back to the radiator.
Radiator hose sizes are 1-1/2 inches ID.
The CHP-CS08 is 1-3/4" x 3/4", so I would guess it is intended for the return line from the heatr.
I've got a 472 motor in my 79 where a 425 came out.
There is virtually no room for the fitting on the passenger side head so what I did was bought  a 1-1/2 inch radiator hose coupler with a pipe fitting side outlet typically used for a temperature gauge and ran my heater supply line (5/8") from there.
Greg Surfas

[NickD]

Hi Greg. Are you saying that the 5/8 inch hose supplies the coolant to the heater core? Would that be considered the pressure line?

I found this part at www.etrailer.com.
1-1/2" Lower Radiator Hose Connector for Kat's Heaters Circulating Tank Heaters
Item # KH28115

Do you think it would work and if so would I use the lower or upper radiator hose for installation?

["Cadillac Kid" Greg Surfas 15364]

Nick
The size is correct but I would not use a plastic fitting.
Greg Surfas

[TJ Hopland]

What are you trying to accomplish here?    I'm not saying what ever it is is a bad idea just thinking if we knew what the goal was maybe we could give better advise.

["Cadillac Kid" Greg Surfas 15364]

Read the first post TJ.  He does not want to use the (almost impossible to get to) head outlet for the heater water on a 425 motor.
Greg Surfas

[TJ Hopland]

All I read is he wanted to know if it could be relocated,  I didn't see him say why.     Engine out of the car?    Going back into a 79ish Cadillac?    Going into something else where there is even less space back there? 

[NickD]

Hi Guys. Engine is in the car. Car is a 79 coupe. I just want to move the line from its present location, due to its inaccessibility for service.