Roadmaster heater issue

started checking out the heater issue on my 94 RM - core is definitely not plugged - good flow in and out.

don't know where to begin now. I intend to drive her up to NY in a few weeks so I'll need heat for sure.

Any ideas?

Thanks in advance

 

Maybe the heater controld valve? Possibly a thermostat as well...

 

Actually The heater core was plugged - it was a guy at the shop who told me it wasn't plugged based on similar temp in and out. When I checked the hoses by feel, one felt cooler to me, so I went ahead and flushed with garden hose. Lots of brown crap came out and now I have heat. Glad it didn't have anything to do with the blend door. I'd hate to have to take apart my pristine dashboard.

Although the heat seems pretty good, I'm not sure it will do for temps I'm likely to run into in NY in a few weeks. Maybe it's still partially plugged. Would it be worth flushing again in a couple of days? Also, would flushing with something like CLR help break up some of the crud?


Maybe a complete cooling system flush with knock sensors out is in order. This scares me. I'd be afraid of messing up the threads or breaking the knock sensors somehow during removal/ replacement.

Would a good reputable radiator shop be the best place to go for a complete flush?

 

A second flush might not be a bad idea, I would maybe PM CatMoldelT (Denny) and see if he knows of any good shops in your area, he lives in FLA and knows his stuff.

 

Ummmm....Florida and heating......just does not work in the same sentance....I'm sure a "Florida" shop can get your heat working if it falls between +70-75 degee

On a serious note, I'd consider changing the heat core. strange things happen when they get cloged,then uncloged....... the sludge acts like a seal, then uncloged like rust, your fine for a bit.....then you leak

 

Leak where?

From the heater core inside the cabin?

 

That's very true Tedy, I have seen that happen before too. Especially if someone at some point ran some stop leak through the system.

 

Sadly, when they do leak....it's 99% allways inside...........

 

First sign would be the smell of anti-freeze, right?

 

...Fogging front glass, and that horrible puddle of anti freeze on the pasenger floor........

 

I hate to even ask, but

How soon would I start seeing signs of leaking after the flush?

Seems like replacing the heater core could be a huge job.

 

Big job for sure, most cores require dash removal. It would be fairly soon IF its going to leak...the first sign is the smell of antifreeze when you first get in the car or right when you turn on the blower motor. Sometimes steam on the windshield as well when the defrost is on.

 

Honestly,,,Could be a day....could be a week.....could be months...could be years.....


It's one of those roll the dice gambels.


Sorry, didn't intent to freak you out, but...been there done that, seen it happen kind of things.



PS....never buy a 80's Fox body with a blown heater core.....your gona spend all day taking apart the dash......can't even imagine what it would be likeon the newer cars...

 

Since I only need heat for road trips to the north, maybe I should consider putting shutoff valves in the heater core lines and cut it out of the cycle when not in use. Might extend the life of the core? Or , maybe make matters worse? Has anyone ever heard of someone doing this?

As I understand it, water is always cycling thru the heater core in RM's. and the air-conditioning is always on as well. What determines the cabin temperature is where the air is directed by vent doors.

 

Bypassing or valving the heater core won't hurt anything, because the fluid in side is not moving or under any heat pressure, so in theory it actually could extend the cores life by not being taxed by heat or pressure. The system will still circulate enough coolant to keep the engine cool.