Last winter wasn't that warm in my car. Even though I flushed the heater core twice. Vowed to solve it this summer. Summer is half over, so this looked cool and I did it. Worthless.





The idea is that you pump a 2 gallon solution of water/CLR through your heater core for a couple hours. I saw almost 0 particulate in the bucket after two hours. After doing all of that, I used a garden hose and blasted it backwards and forwards about 20 times. Each time I got more particulate out of the heater core. As long as I was there, I removed the radiator and flushed that the same way. Got nothing out of that. Squeaky clean.

 

When I "freshened up" my cooling System, I flushed the radiator, using the reservoir tank and the drain plug. I did this 3 times in a row (with a garden hose and the heater on "HI" - and "Full blast" the entire time - with the car running of course).

I them filled it up w/ a 50/50 mix and that worked great.....and is still working great.

 

Thanks ^^^^ but i did at least that last fall. Had great heat for about a month, then it started cooling off again. So right now I'm running pure h2o. Every day i drain the radiator and top up with new water. Before i put g12 in there i'll back flush the heater core again like I did the other night till I get 0 particles out of there.

 

Thermostat?

.

 

Nope. My gauge always points straight up, and when I bring up the coolant temp on the climate control, it's always 90C. And I always have great heat right after I flush the core. But then the flow problems creep back over time.

 

Algae? Mold?

 

I'm not sure. That's why, for the second time in 24 months, I completely flushed everything. Drove all weekend on pure water, now I have G12 in it again. I'm giving up. I'm going to do a heater core soon. Something in the core is disintegrating and turning it into a big filter.


Oh, and after all that work my heater core tubes look like this:

 

The best way to dissolve plastic is put it in a car. It will last eons in the dump.

The core really isn't that bad to do. Just be methodical and take lots of pics. Looks like it was time. For the others- if you change the coolant every 2-3 yrs or 30k you can avoid this or prolong it. The coolant can get electrolysis as it gets older and I think that helps the plastic gets brittle. For those of us that bought ours at 100k plus or 10 yrs old the damage may have been done already. I just always try and prevent problems. Especially 8 hour repair ones.

JMO

 

I did this on my dear departed 96 A4, and on a 2001 A4 flipper I made a buck on. I agree, it's not a greasy, knuckle-busting, pull-the-tranny kind of job. Just methodical grind it out wrenching. I think the best thing you can have is a good cordless screwdriver with an adapter that turns it into a 1/4' drive ratchet. You can have that pass side airbag out in about 5 minutes versus 20.

 

This sucks. I hope to never have to do this on my car.