Now you know! Let's hope it's something silly like you said above. If the hoses are in good shape, just make sure they're clean and plug them before you pull them through the firewall. If they're in need of replacement, just cut them short and plug them before you pull them through. WD 40 and a rag works well for cleaning rubber hoses, btw.
My trick to save the carpet is to remove both heater hoses from the engine connections then simply use the garden hose to flush out the remaining coolant. This simple act allows only fresh water to spill from the hoses and heater core instead of sticky coolant that refuses to ever dry up. Now a couple of towels snuck out of the house then laid in the vehicle floor make cleanup so much nicer. You also get to quickly find out if the heater core is really plugged when you squirt the water in one hose at a time. Who knows, you might get lucky and blow out the offending plug and not have to remove the heater box. If you do blow out a mystery plug, keep an eye on the heater making sure you still have no leaks inside the car. If you do establish good flow thru both hoses with no obvious leaks, re-attach the hoses to the engine and fill the system then see if you now have heat.
When I bought the car, the PO made a point to mention that he had rebuilt the heater box. And it looks like it. It is shiny and new ... and clogged. Sigh ... Oh, well, it could be worse. It could be a <shudder> Chevy! Joseph
Or a Buick Roadmaster. If you get lazy on maintence on those Buicks, the coolant has an unfortunate tendency to plug the heater core. Bought one from Ohio that suffered a plugged heater core but that might have saved the car from a rusty fate because it didn't get driven in the winter due to no heat. Did the garden hose routine and blew out a stringy, snotty looking blob of gunk that had formed out of that nasty orange coolant. Flushed the whole system then converted to conventional green coolant mixed half and half with distilled water. Heat has worked flawlessly now for four years. No silver lining in that cloud though, the air conditioner evaporator core developed a pin hole in a weld joint a month later after the heat was fixed. That was a fun repair.
"The Lord Giveth, and the Lord Taketh Away." Had a good customer once, who had us convert and charge his Toyota R-12 system to 134a; a few weeks later, he brings it back, says it quit working a couple weeks after. So my boss hooks it up, about 15 pounds of pressure. So he tries to evac it, so we can check all the o-rings, but it just won't pull vacuum...???? We eventually figured out, the system was open to the atmosphere with a gas tester, and so my boss pressurized the system with nitrogen, when we heard hissing inside the vehicle. Turns out, the customer had gone to a stereo shop, where their tech had drilled a hole through the dash...and the evap case, and the core. I think it was a 5/16" hole, it was pretty big!
A now out of business electronics company ( Circuit City ) in Nashville installed a high end stereo in a 94 Town Car for a friend. He drove home to his new house, pulled in the garage and went inside. Once inside he realized his phone was still in the car so back to the garage. He was damn lucky he went back for the phone as the instrument panel was blazing. He got the fire out but not before the interior of his 24K mile car was destroyed. Circuit City in the settlement took him to Nashville where they said pick out any vehicle you want. He came home with a new $90 K Navigator and I bought his burnt Lincoln for the virgin running gear. Must not have been the only one as they were out of business within a year. Sometimes there is a silver lining to those clouds.
Okay, my Google searches have come up with trying to flush the radiator core, in hopes that I can dislodge the clog. People have used CLR, citric acid, muriatic acid, vinegar, air, and water. I even found a post where someone used beer! Okay, it was for him while he was flushing out the system, but you gotta enjoy what you're doing. Actually, my biggest concern isn't the heater core itself, but what crud is elsewhere in the cooling system that can re-clog the core. Should I drain the block, remove the thermostat, disconnect the bottom radiator hose, and just flush it out with the garden hose? Should I let it go, until the heater core clogs up again (then I'll know that there's still crud in the system)? Any suggestions as to what to try first, or what to avoid? I'm thinking of just starting with the garden hose in the core outlet hose, then the inlet hose, and go back-and-forth for a while. But if anyone has any particular experience or horror stories, I'm all ears. Joseph
Nowadays shop should be able to flush the system fully, but you can do the same thing provided the heater core isn't clogged. Once you solve that you can get a few gallons of distilled water and run the engine to operating temp with the upper hose disconnected at the radiator. As the fluid expels from the upper hose you must keep adding distilled water to the radiator until what comes out is clear. I know this isn't environmentally friendly but it was a pretty common practice back in the day with a garden hose providing the water. Now nobody wants to put water with contaminants into their system so this should work with a few gallons of distilled water standing by. Or you could take it to a shop. Your call.
Sounds messy and wet. Perfect for a January afternoon! Maybe I'll just settle on my heater core for now, and deal with the system in the spring, when we get warmer weather. Joseph
I got back to my heater issue today. I removed both lines at the engine. The fitting at the intake manifold dumped coolant out. The fitting at the water pump didn't. I flushed the lines with a garden hose, and the lines/core were clear. They spit out rusty water (more water than rust), but not really any coolant (the system only had water when I bought the car, so I replaced it with pre-mixed coolant). The fitting at the water pump was blecchy white sludge. I cleaned out the sludge, popped it all together ... and still no heat. The source line to the heater core was hot. The sink line from the core was hot, close to the back of the engine bay. I don't know if it's stock, but the line runs close to the inner fender, then comes back in to the water pump. The hose is still warm, but not hot. I'm wondering if I'm just feeling the heat from the engine, not the water inside. It kind of sounds like there's some kind of obstruction at the water pump. Is there some way to check? Should I try to clear it out with an air compressor? Should I say to @#$%&* with it, and just replace the water pump? Should I replace the whole thing with a Toyota? Just kidding on the last one! Any words, wise or otherwise? I've exhausted my four-letter repertoire . Joseph
A fully stuck open t-stat can; to find out if it is, take two boards and two c-clamps, clamp the boards just enough around the upper hose to restrict (not stop) the coolant flow, if there is any. Then check the heater output. Remember, if the cooling system is up to snuff, you can only hold a hot hose for a few seconds before it's mighty uncomfortable to hold.
It was hot/warm, but not to the point where I had to let go. I picked up a new thermostat this afternoon, and will install/replace it tomorrow. Joseph
