Cocking about trying to clean an expansion tank - PeachParts Mercedes-Benz Forum

Stretch · #1 09-12-2015, 02:37 PM

G'day Folks,

I've been messing about with a little experiment trying to clean out gunk from an expansion tank. The gunk came from a failed head gasket - and then there's the age yellowing that probably will never go...

...so far it is a list of what doesn't work and one thing (so far) that has given the best results.

I started off with baking soda - forgot to mention this the first time I posted...

...sorry no pictures - it didn't work...

...Then I tried vinegar (hey it is pretty good at cleaning burnt off crud on saucepans!)

Unfortunately I only had red wine vinegar.

It managed to stain the inside a bit more.

So OK after that I thought - engine degreaser

It works well on mucky engines

Not so good inside grotty expansion tanks though

(It looked like the red wine vinegar staining was planning to stay)

Stretch · #2 09-12-2015, 02:40 PM

Next up Vanish stain remover

Oxi action (don't ya know)

Can ya see the bubbles?

It was definitely doing something

Red wine staining is gone!

And some of the gunk is gone too.

I thought it might be the work of bleach - so I tried a heavy dose of that but it didn't seem to make much difference

Stretch · #3 09-12-2015, 02:41 PM

So I'm planning to carry on with the stain remover stuff and see if that will get more of the stuff out...

...unless of course someone here has a better idea...

charmalu · #4 09-12-2015, 04:52 PM

You are going to spend more in cleaning products, than if you just bought a new one. LOL

I know, that isn`t the point. This is a DIY group of enthuiasts and we ain`t going the direction of new.

Bur just in case you get weak kneed........
1992 Mercedes-Benz 190E 2.3 Sedan - Radiators - Page 3

Great work though.

This is what you are striving for.

Coolant

Charlie

Sent from my pos computer

uberwasser · #5 09-12-2015, 05:29 PM

I just installed a new one on my '85 a while ago, mainly because I figure it was now the weak link (in terms of cracking plastic) after replacing the radiator.

The side benefit is how good it looks!

Still, I'll follow for curiosity. Plus what works here may work inside the brake reservoir too. Those aren't nearly as inexpensive to replace as the expansion tanks, for some reason...

Simpler=Better · #6 09-12-2015, 05:37 PM

Tape off a line to use for checking the level.

Paint it your favorite color

Smile

Mxfrank · #7 09-12-2015, 05:37 PM

I tried to show you:

What's inside that header tank?

The stuff inside is a combination of who knows what...motor oil, oxidized glycol, dissolved bits of rubber hose, ancient silicate deposits, biological contaminants; a real witches brew. I found it hard to remove mechanically, even after sawing the tank open! On top of the difficult material, the only entry in or out of the baffles are tiny holes. You may not even be reaching the rearmost baffle with your cleaning products.

You might be able to do it with muriatic acid and a lot of patience, but then the filler neck would be compromised. And the resulting hydrogen gas would be an explosion risk.

If the discoloration really bothers you, a new tank is the only way. I wish it wasn't so.

leathermang · #8 09-12-2015, 05:43 PM

I would put a half cup of crushed walnut shells, a squirt of Joy dishwashing liquid, a little water, a little sand blasting sand, and rotate it a lot in all directions.... then repeat if necessary....

Stretch · #9 09-12-2015, 05:54 PM

Quote:

Originally Posted by charmalu

You are going to spend more in cleaning products, than if you just bought a new one. LOL

...

Ha! Already done that =>

Quote:

Originally Posted by Mxfrank

I tried to show you:

What's inside that header tank?

The stuff inside is a combination of who knows what...motor oil, oxidized glycol, dissolved bits of rubber hose, ancient silicate deposits, biological contaminants; a real witches brew. I found it hard to remove mechanically, even after sawing the tank open! On top of the difficult material, the only entry in or out of the baffles are tiny holes. You may not even be reaching the rearmost baffle with your cleaning products.

You might be able to do it with muriatic acid and a lot of patience, but then the filler neck would be compromised. And the resulting hydrogen gas would be an explosion risk.

If the discoloration really bothers you, a new tank is the only way. I wish it wasn't so.

A spade is a spade - the thread is entitled "Cocking about..." for a reason!

The fat lady isn't singing just yet - I have a few more ideas that might work.

I don't expect it to be as clean as the new one but if I can get out most of the muck then perhaps it might be of use to someone in the future.

My problem with going straight for the new tank solution is that you need to be pretty sure that there's no more junk in the old system otherwise you end up mucking up your new expansion tank...

...may be there's more to this cocking about after all - clean up the old as best as possible - run some fresh coolant for a while - coolant flush - new expansion tank - new coolant => proper job?

Stretch · #10 09-12-2015, 05:57 PM

Quote:

Originally Posted by leathermang

I would put a half cup of crushed walnut shells, a squirt of Joy dishwashing liquid, a little water, a little sand blasting sand, and rotate it a lot in all directions.... then repeat if necessary....

The structure isn't what I think you assume it is like.

Look at Mxfrank's thread to see pictures of an expansion tank in bits. The holes for the fluid between each section are really small. If you put any solids in the tank there's a good chance they'll get stuck in there.

I'm fairly sure I'm going to keep trying fluid only solutions

Stretch · #11 09-12-2015, 05:58 PM

Quote:

Originally Posted by Simpler=Better

Tape off a line to use for checking the level.

Paint it your favorite color

Smile

Then I save money on coolant too!

Stretch · #12 09-12-2015, 06:00 PM

Quote:

Originally Posted by uberwasser

...Plus what works here may work inside the brake reservoir too. Those aren't nearly as inexpensive to replace as the expansion tanks, for some reason...

Oh yeah - I hadn't thought about the brake reservoir discolouration...

...damn it!

leathermang · #13 09-12-2015, 11:59 PM

OH... .I thought you were wanting to seal up those holes.....

MBeige · #14 09-13-2015, 01:33 AM

How long did you let the products sit inside and mix? Maybe some of them take some time to chemically react to whatever is inside.

Given enough time surely one of the more potent ones will work if you leave the reservoir to soak in the solution long enough.

Stretch · #15 09-13-2015, 02:16 AM

Quote:

Originally Posted by MBeige

How long did you let the products sit inside and mix? Maybe some of them take some time to chemically react to whatever is inside.

Given enough time surely one of the more potent ones will work if you leave the reservoir to soak in the solution long enough.

Good point - I forgot to say.

Here's a summary so far

Baking soda - 24 hours [No visible effect]

Red wine vinegar - 24 hours [Left more staining!]

Engine degreaser - over night (say 16 hours) [No visible effect]

Vanish stain remover - over night (about 16 hours again) [Lots of bubbles - removed staining - best effect so far]

Bleach - over night (about 16 hours) [No visible effect]

{Everything has been mixed with tap water expect the vinegar}

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