Ok so i had to replace the heater core on my 88 f body i did it the hard way and removed the entire dash when i got the new one and dash back filled her up with antifreeze started it up let it warm up to 180-200 degrees burped til all bubbles were gone i noticed that it was barely blowing hot kinda like that luke warm i know the blend door is working cause when i switch it from cold to hot i see the actuator move left to right (digi dash controls) this heater core was also bought from autozone could that be a big problem why its only blowing out luke warm (name of company was spectar cooling and heating)

 

More likely, it's not hooked up right...

Should have one hose going to the intake manifold, and one going to the water pump or to the cold-side radiator tank.

Also it will be a bit disappointing if there's no thermostat so in case that's the situation, install one.

 

It's probably hooked up right, I'm sure the hoses were returned the way they were removed.


There could still be an air bubble in there. Re-check. Also, your blend door actuator is still moving, but make sure it's moving through the whole stroke. I had the blend door partially seized on an electronic GTA, just enough that the actuator didn't have enough power to move the door completely. It's easy enough to check, just detach the actuator and see if you can move the door further by hand in order to get heat.

 

Feel the retun hose, is it lukewarm also? Is the hot water valve working? Did you hook the 2 hoses up right? If swapped you can get air trapped in the core. The inlet needs to go to the low side and the return on the high side. IF I'm not mistaken the smaller pipe (the one closest to the core) is the inlet and the larger pipe the return

 

you got a "spectra premium " made of ALUMINUM !! . it never will produce heat . your best bet is to have your OE copper/brass core repaired, and re install it. oh , and stay out of auto zone

 

Nothing wrong with the heater core in question. There's MILLIONS of aluminum ones in the world working perfectly fine.

Nothing wrong with getting it from AZ either. Coulda got the same brand (which is actually Spectra, by the way) from radiators.com, 1AAuto, any of a long list of other parts stores, etc.

What's important is what's IN the box; not the name ON the box, or the name on the outside of the building the box is IN.

Still comes down to putting hot water through it... my bet is on the hoses being hooked up one to the WP and one to the radiator, because the one to the intake is either "hard to get to" (the version in the rear) or "ugly" (the one in front).

Twin is correct about the fitting size: the 5/8" one is the hot side and the ¾" is the cold return. The 5/8" one should hook to the intake, the only available source of hot water under water pump pressure, which tends to force said hot water into it; the ¾" one should hook to either the rad or the WP, both of which are on the cold side of the system and have water pump suction on them tending to pull cooled water out.

 

Sorry for tue late reply here is how i have it set up im using a hsr so its tough using the water ports since the the throttle body is right above and fittings so the way im running them are out the top of the water pump which is a 5/8 hose thats the inlet that goes into tue heater core the the out running back along side the frame rail to the radiator just below the overflow fitting

 

Heater control valve working properly? Or, no heater control valve?

 

Well that's your problem, right there: you have them routed EXACTLY as I described above that WON'T work.

You have both of them hooked up to the cold side of the system.

You MUST run one from the intake (hot water) which will be the 5/8" one, and one to EITHER the WP or the rad (the ¾" one).

Hook it up right and tell us how it works.

 

Yea I have the spectra too, after I replaced the thing during my rebuild (nothing wrong with the old one - it was just old and I didn't want coolant in the car of it malfunctioned), I had a funny issue with it not producing heat.

I burped the system in my own way, made sure the hoses were hooked up right. Then I put the valve back in and cut up the hoses to make it fit proper. I drained and refilled the coolant and made sure no air in system- presto works fine. Then again I have the LS water pump so I don't have as much plumbing as the SBC

 

yea just need a way to route the hoses a different way im using a hsr setup so the water outlets on the intake are under the throttle body which makes it tough for hose routing and fittings to install but ill figure something out

 

Yup; get that fixed, should straighten it out.

Try things like 90° fittings, molded hoses you can section together, etc.

 

ok for the heater control valve which side do I hook that up to

 

Don't know off the top of my head... but at this time of the year in the place you are you could just eliminate it and run the lines straight from the heater core to the pressure and suction points, and figure it out later.

 

This is how it is set up stock for TPI.

 

that's how it runs on a non ac car with no oil cooler. An AC/oilcooler has a T-ed off section on the hard line that is the byoass foir when the heater valve is closed. The oil cooler runs off that in series.

 

This setup would work perfect if I was using the tpi but I'm using a totally different intake

 

ok got a update I was wondering I removed the heater control valve and also hooked up the inlet (hot side) to the intake and the outlet going to the radiator (cold side) I was wondering what do I do with the vac hose that hooks up to the heater control valve I know it only works off of part vac is it really needed