Citric acid flush, no step in the instructions for REALLY stupid people like me! - Page 3 - PeachParts Mercedes-Benz Forum

300DPETE · #31 11-21-2005, 02:40 AM

Quote:

Originally Posted by ke6dcj

Since you did the Citric Acid flush, you should run the MB De-oiler as well.

Regardless, flush at least three times with fresh water (that is, fill, run for 5-mins.; cool; drain; repeat), before refilling with 50/50 mix of distilled water and MB antifreeze (or Zerex G05) PREMIXED.

:-) neil

I thought you were supposed to degrease before the citric acid flush, and then just flush with plain water 4-5 times after the citric acid flush. Are you also supposed to degrease after the citric acid flush?

coelcanth · #32 11-21-2005, 04:04 AM

i think, most of the time, the first step to anything is:

pile all the stuff in front of you and ask yourself: 'ok, how am i gonna do this... what is da best way??'

i think you got the steps right... remember this thread:

Flushing Radiator

degrease-->acid flush-->rinse/flush many times-->fill

boneheaddoctor · #33 11-21-2005, 09:01 AM

Quote:

Originally Posted by 300DPETE

I thought you were supposed to degrease before the citric acid flush, and then just flush with plain water 4-5 times after the citric acid flush. Are you also supposed to degrease after the citric acid flush?

No..you did it right.....drain, flush, deoil, flush, flush, citric acid, flush, flush, flush, flush, new correct anti-freeze.

boneheaddoctor · #34 11-21-2005, 03:49 PM

Quote:

Originally Posted by Brian Carlton

You won't blow out the heater core unless you have a 1" air line to the hose. A 1/4" air hose won't pressurize the heater core, especially with the far end wide open.

But, I agree with the garden hose idea............much easier to rig up........gets the same results.

if there is water in it untill that water clears the core you can and will see a surge of whatever pressure is in that air line.... cooling system never sees more than 15 psi pressure....120psi is going to damage something.

nscarr · #35 09-13-2007, 06:06 AM

I thought I'd add my experience with the citric acid as I was surprised by the results.

On the 300D, I followed the draining, rinsing, degreasing (~16 oz Shout), rinsing (x2 for me), and adding citric acid solution (2.2 pounds dissolved in ~4 L hot water). I'd read that people drove >100 miles with the citric acid so I thought I'd give that a try to de-scale.

In the meantime... I started the 300TD on the same regimen but after I added the citric acid it clogged big time with the chalky goop. I couldn't even go 25 miles without the temperature approaching 110 (when I'd stop to cool off). Removal of the radiator cap showed full-on blockage, requiring gallons and gallons of water to suspend the chalky goo and flush it out.

After the experience with the 300TD I decided to flush out the citric acid solution from the 300D after ~75 miles, and while it was chalky it wasn't nearly as bad as the 300TD. So now I'm on to the rinses and fill with Zerex.

As a source for citric acid, try Zenith Supplies (in Seattle) at http://www.zenithsupplies.com/
$2 per pound for me. And while I'm hardly one to harp on safety, a chemist friend at work has a nasty scar ~15 years old from a citric acid solution; I don't know the concentration he was burned with, but this stuff apparently can burn.

Thanks for all of the great information on the board, and just to confirm: The chalky goo is the scale?