Trevor C.
New member
Hi all,
I thought I'd send this along with the weather getting colder; my heater core was clogged really bad. I found a link on the Audizine web site to unclog it using oxalic acid & sodium carbonate link. It worked really well! Not sure if this has been posted before.
Here are the highlights and a link to the original post. Hope it helps!
[*]If you have trouble slipping the tubing on the heater core pipes just dip the ends of the tubes in boiling water to soften them(probably not a big issue in CA but in colder climates vinyl gets very stiff).
[*]Suspend both tubes with a bungee cord from the hood latch mechanism so they don't fall down and spill chemicals on you or your car.
[*]Blow the coolant out of the heater core.
[*]System flushes contained 9 ozs oxalic acid and 2 ozs sodium carbonate. The volume of the heater core is really small, maybe a cup and a half, so you don't need a lot of either chemical to do this. I used maybe a tablespoon or two of oxalic acid with that cup and a half of water, less for the sodium carbonate. You should wear goggles and use rubber or nitrile gloves just to be on the safe side. Oxalic acid is what makes parts of the rhubarb plant poisonous.
[*]Use a funnel and pour in the oxalic acid/boiling water solution until you can see liquid a few inches up both tubes from the point where they attach to the heater core pipes. I didn't cap either tube.
[*]I would periodically blow gently in one tube to move the solution back and forth a little. I let it sit for 20 - 30 minutes, blew it out with an air compressor (into a clean white catch pail so you can see what's coming out), put in some more hot mixture, agitate, blow it out. I did that about 4 times.
[*]Then boiling water and sodium carbonate for ten minutes. Don't leave the sodium carbonate in longer than that in case you having aluminum tubing in your heater core as it's mildly corrosive to aluminum. But I think that's why it's also effective at getting more crap out of the core.
original post: Heater Core Flush Question
I thought I'd send this along with the weather getting colder; my heater core was clogged really bad. I found a link on the Audizine web site to unclog it using oxalic acid & sodium carbonate link. It worked really well! Not sure if this has been posted before.
Here are the highlights and a link to the original post. Hope it helps!
[*]If you have trouble slipping the tubing on the heater core pipes just dip the ends of the tubes in boiling water to soften them(probably not a big issue in CA but in colder climates vinyl gets very stiff).
[*]Suspend both tubes with a bungee cord from the hood latch mechanism so they don't fall down and spill chemicals on you or your car.
[*]Blow the coolant out of the heater core.
[*]System flushes contained 9 ozs oxalic acid and 2 ozs sodium carbonate. The volume of the heater core is really small, maybe a cup and a half, so you don't need a lot of either chemical to do this. I used maybe a tablespoon or two of oxalic acid with that cup and a half of water, less for the sodium carbonate. You should wear goggles and use rubber or nitrile gloves just to be on the safe side. Oxalic acid is what makes parts of the rhubarb plant poisonous.
[*]Use a funnel and pour in the oxalic acid/boiling water solution until you can see liquid a few inches up both tubes from the point where they attach to the heater core pipes. I didn't cap either tube.
[*]I would periodically blow gently in one tube to move the solution back and forth a little. I let it sit for 20 - 30 minutes, blew it out with an air compressor (into a clean white catch pail so you can see what's coming out), put in some more hot mixture, agitate, blow it out. I did that about 4 times.
[*]Then boiling water and sodium carbonate for ten minutes. Don't leave the sodium carbonate in longer than that in case you having aluminum tubing in your heater core as it's mildly corrosive to aluminum. But I think that's why it's also effective at getting more crap out of the core.
original post: Heater Core Flush Question
