Heater core plugged...again

[brothapig]

Ok, I guess I don't need any technical help, since I know what I need to do, and unfortunately (or fortunately) I've done it before. I just don't know why it's happening.

I've flushed my cooling system twice now in a little over a year. When I bought the car it had been sitting, so I was not that surprised when I had no heat in the car. Flushed the system, filled with new Prestone (the stuff that mixes with Dexcool) and everything was fine. A couple of months later, same thing. I figured I had missed some crap last flush. That was a year ago, and it's acting up again.
I have some heat, but not much. It is taking a looong time to heat the car up inside (and it's getting cold outside!) Am I missing something here when I flush the system? Is there any kind of detergent I can use to help clean the system? I guess I'm just making sure I haven't missed anything.

BTW, when I flush the system, I am taking the thermostat housing off and the thermostat out, and sticking a garden hose in and just letting it run. (the water, not the engine) I do get a lot of crap that comes out of the heater core (I flush that separately) I think there is a restrictor inline to the heater core; can I take that out??)

[Formulaboy95]

I was thinking about using a shop vac on mine. It should work pretty good. The lines on the firewall should go to the heater core I guess. Can anybody verify this.

[Joe 1320]

I was thinking about using a shop vac on mine. It should work pretty good. The lines on the firewall should go to the heater core I guess. Can anybody verify this.

Yup. If you have to do a second flush, it was likely that you didn't get the rest of the crud out from somewhere else..... the heater core is where it ends up.

[Joshu]

Yeah mines plugged up too. Joe maybe you could help. My engine temp goes up and i loose heat (goes to like 230-220) then plumments back down to 195ish and I have heat. It goes up and down....sound like a clog? Thanks!

[Disifer]

@94 white devil
It sounds more like you have air in the lines. My 89 did that when my coolant got low from a leak.

[Joshu]

any idea how it could leak in?

We flushed this thing 3 times while doing the headgaskets cause it was so clogged.

[Disifer]

One of my hoses had a pinhole in it that wouldn't started spraying coolant until the engine was hot. It left a pretty nice sized puddle on the ground and the underside the hood was soaked.