airborne1942

is there suppose to be a restrictor in the heater hose on a 1970 Cutlass 350 with out AC?

MDchanic

Not specifically, but the nipple that screws into the intake manifold provides a restriction.

- Eric

Allan R

Is there a problem with heat or lack of heat to the heater core?

Tiha

would be great if some one has a part no. (dorman or any other brand) from these nipple !

thanks

joe_padavano

Inline Tube sells the correct nipple with restrictor for $18. Note that the 1964-70 factory intakes use a smaller NPT than the 1971-up intakes. There is no telling what thread is used on aftermarket intakes.

airborne1942

no, there are no problems, I'm replacing the heater hoses and wanted to put it all back factory, I have all the correct hoses, and I seen reproduction from inline tube, heater hose fitting that goes in the back of the intake, in the ad it says with built in restrictor, so I didn't know if there suppose to be a restrictor in the heater hose or in the heater hose fitting on the back of the intake, or no restrictor at all. my heater works fine right now. I just wanted the correct way to put it back together. thanks! Brian

joe_padavano

The reason for the restrictor is to avoid overpressurizing the heater core, leading to leaks. On A/C cars, the heater control valve provides this restriction, but on heat-only cars the restriction is built into the nipple.

airborne1942

my intake looks like it has the original fitting on the intake manifold for the heater hose, so I should not have any problems if I put the it all back together.

Fun71

FYI, the restriction is simply a smaller diameter hole (1/4" maybe?) in the much larger diameter hose fitting. You should be able to look at the inside of the fitting and see if it is restricted or not.

olds 307 and 403

Pretty sure the SBO Performer, along with the RPM has 3/4" NPT threads.

Fun71

Yes, those two have the larger size opening. I had to use a reducer bushing on my cars.