Read this before replacing your heater core! (heat not blowing hot)

[freedom_in_4low]

So there could be more?

there are 28-34 of them in a heater core (depending on the brand they have different numbers of tubes), with about half of those having potential to escape since they don't have to get around a u-bend first. Some of the ones on the opposite end of the tank from the connections would probably have a hard time making the corner as well, but at least 4-6 have an almost direct shot through the outlet, each 6-7" long.

Thinking about the path it would have to take, I don't think it can go through the water pump more than once. To wind up jammed in the thermostat - it had to push through the heater hose, into the water pump inlet tube, through the water pump, block, and head. If any pieces got through the thermostat they'll get trapped in upper tank of the radiator because they are too big to pass through the radiator tubes, otherwise they bypass the stat and head back for the heater core where they would jam up on the inlet side of the heater core tank.

It's possible that's just one of them that's broken into multiple pieces, but i would not be at all surprised if there were more behind the water pump, as that's the slowest flow in the system and most likely spot for them to settle.

 

[Coadster32]

While I don't agree that plastic turbulators are the cause of any performance issues I do agree they're a problem if they're migrating through the system.

Has anybody found these in an APDI brand heater core? Their stock photos look a little different than most, in that the tank matches the OEM color and the tubes actually look copper.

Would like to bump this back to the top for others to chime in on. A new heater core may be in my future, and the Performance place has been possibly been sourced out lately.

 

[freedom_in_4low]

I bought one of those, as well as two others, all had the plastic turbulators. OSC appeared to have the same ones, but in a smaller tube, which may make it harder for them to escape and end up in the block, but I have not used one.

I haven't seen anybody claim any of the aftermarket ones put out the same temperature as OEM. Note that this is not the same as saying they don't do as much heat transfer - it's possible to flow more air that isn't as warm, meaning it won't give you the same sensation on your feet but it'll still warm the interior just as effectively. But no data exists for that, either, since it's not that easy to measure airflow CFM.