Coolant flush - best coolant for 300SDL - Page 3 - PeachParts Mercedes-Benz Forum

Squiggle Dog · #31 10-11-2018, 05:01 PM

Not to mess with what already works, but how do you guys think oxalic acid compares to citric acid? That's what I've used in the past (used to be the active ingredient in old-school radiator flushes) and it's seemed to work, but I've also never used citric acid.

Alternatively, Evaporust is supposed to work very well at cleaning out rust and gunk, though it's very expensive to do so.

Zulfiqar · #32 10-12-2018, 10:47 AM

Quote:

Originally Posted by Squiggle Dog

Not to mess with what already works, but how do you guys think oxalic acid compares to citric acid? That's what I've used in the past (used to be the active ingredient in old-school radiator flushes) and it's seemed to work, but I've also never used citric acid.

Alternatively, Evaporust is supposed to work very well at cleaning out rust and gunk, though it's very expensive to do so.

The stuff is much more stronger than citric acid and requires neutralizer otherwise it will start to eat into gaskets. Its also a bit difficult to get compared to citric acid.

Squiggle Dog · #33 10-12-2018, 02:07 PM

Quote:

Originally Posted by Zulfiqar

The stuff is much more stronger than citric acid and requires neutralizer otherwise it will start to eat into gaskets. Its also a bit difficult to get compared to citric acid.

Okay. I've run washing soda through the system afterwards to neutralize it. I just buy mine at Ace Hardware. They sell the oxalic acid as "Savogran Wood Bleach" powder. Though it's not as good as Evaporust, it makes a good rust remover soak.

vwnate1 · #34 10-12-2018, 04:44 PM

It's way too strong, like Vinegar .

You may not see any problems right away but it's not what you want in any cooling system .

Th reason Citric Acid works so well is : it's gentle and takes a day or two of driving it to allow it to work without damaging anything .

cmac2012 · #35 10-25-2018, 01:58 AM

Quote:

Originally Posted by Diseasel300

With the thermostat closed, the water pump only recirculates water through the block. If you have water in the block, it will only recirculate that until the thermostat opens and begins to circulate the acid solution. While you can do that, it's going to leave the acid in the system for a long time to do the same job compared to a blocked open thermostat.

The thermostat in a bypass cooling system does 2 things:
1: It opens the port for circulating coolant through the radiator.
2: It CLOSES the port for recirculating coolant through the block.

With no thermostat in place, you're recirculating a large amount of coolant through the block that normally should be circulating through the radiator and getting cooled. The result is rather rapid overheating, especially if you have lime in the radiator causing a restriction.

Quote:

Originally Posted by Zulfiqar

If you dont have a stuck open thermostat, find a rubber cork that will fit into the round hole you see in the water pump housing when you remove the thermostat. Once this is blocked closed, The path of liquid is 100% engine to radiator.

so the procedure goes like.
drain from both taps
remove t stat
shove cork into bypass porthole
install tstat cover back without t stat in place (but some gasket to seal the thing)
fill up with acid mixture making sure no air is trapped
start engine run at 2000 rpm for 20 minutes.
let it cool off
drain the acid from both taps - leave them open
remove the t stat cover and cork you shoved in
remove a heater pipe - and shove a garden hose at low pressure into it to flush the acid out from everywhere. (or use the contraption I posted above)
install T stat and cover.
fill er up with coolant mixture.

Good info. Somehow I missed these a few weeks back.

Hit Man X · #36 10-25-2018, 08:13 PM

Quote:

Originally Posted by Squiggle Dog

Alternatively, Evaporust is supposed to work very well at cleaning out rust and gunk, though it's very expensive to do so.

I used it on one of my turbo E23 BMWs... works awesome as the system was full of ****. Buy a five gallon bucket for about $90. Steal about two or four quarts. You are set. Rest distilled water.

Sticks in my mind I had to let the car run for about an hour? Probably just drove it around the block mostly. What came out was disgusting. Also works badass for tools among other things.

Yes, I would do it again on a neglected system. On a clean one? Drain and fill, get on with life.