Flushing out Heater Core
 

My heater in my Olds has stopped working; actually, it's effectiveness diminished slowly over time and it no longer works. A friend, who is a mechanic told me that it is very likely that the heater core is simply clogged and needs to be flushed out.

Is there an easy way to do this? I know that on many American cars, replacing a heater core is a major job that involves taking off the passenger side dash and/or fender! Can anyone steer me toward an easier solution?

I'd say it's usually tough on any car. I've replaced a few on Japanese cars and they were a bear. Sure it's not leaking?

If the inlet and outlet tubes are available on the engine side of the firewall then perhaps you can do a simple pressure test with a tool like a Mighty-vac.

If you have to remove I'd suggest bringing it to a radiator shop (if they still exist) and have it steam cleaned, boiled/soaked, pressure tested, repaired (if needed) and painted. Many don't bother as the time to R&R demands replacing with new.

You might try flushing. Check an auto parts store. Prestone used to sell a flush kit...it involved placing a hose fitting in one of the heater lines...I still run one on my old Dodge. Pretty cool, it allows you to use hose water pressure to "backflush" the entire system. Auto parts store also sell a bottle of stuff you can use prior to a coolant change designed to eat lime buildup, etc. Like I said, MIGHT work...

Where are the outlets for flushing? Are they in the engine bay, on the "easy" side of the firewall?

The overflow comes out of the radiator cap fitting. The kit includes an L shaped plug-in unit so the flow can be directed.
Mine was cheap..$10 range if I recall. But I bought it over 20 years ago...

Well, I have no idea what car we are talking about so this advice is general. Yes, there are heater hoses that come from the engine bay to the heater core. They generally pass through the firewall at some point, since that is where the average heater core lives. Disconnect both of these hoses at a convenient point and run water through them. Run a flush chemical through them if you want; you can get some at any parts store. I'd flush it backwards; run the water into the output hose from the heater care. If you don't know which is which, two minutes Googling the internet ought to cough up a little help.

Of course, this may not be the problem. If you have a car that runs heated water through the core at all times and regulates the temperature by blending warm and cool air, you may have a problem with the other parts of the system.

JR