How can you clean-flush your heater core Audi A4 2001?
You can take your car down to you local garage and get him to
acid flush the entire system or just the heater core. Like me you
might find this does nothing to the blockage. Here's what I did and
it worked. Remove the inlet hoses to the heater core at the
bulkhead manifold (take care with the coolant spillage). The left
hose is the return, it has a small hole in the top for air purge.
Attach 2 utility hoses to the inlet, let the right one run to the
ground and put a funnel in the left one (return side). Boil 3
gallons of water. Add water slowly into the funnel. While adding
water add 1 teaspoon of Oxyclean for every couple of cups of water.
Keep doing this until the solution has been passed through the
heater core. Flush through with clean water (use garden hose for
some pressure) for a good period to remove all solution deposits.
Re-attach the cooling lines to the inlet manifold. Start the engine
have the revs up at around 2000rpm, put the heater on full blast.
Bleed air from the return line (just pull the return line off a
little so that air can excape from the small hole) this may take 10
minutes so be patient. You are done. Re-attach and clamp the hoses,
you should have, like me a clear heater core. Oxyclean is a laundry
product and should not damage your heater core (no promises though)
It works by decaying organic materials.