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Cleaning stains from the inside od a plastic expansion tank
MalP - 1/9/25 at 12:02 AM

The inside of the plastic expansion tank on my car has a brown stain on it which makes it difficult to see the water level.

I have put in the washing machine with detergent and stain remover powder which has been partly successful.

Can you suggest better ways of cleaning it?

(my dish washer is out of order)



Malcolm

cliftyhanger - 1/9/25 at 06:24 AM

I have tried a few things, but the stain seems difficult to get out. I just had a dig through a few ideas from the interweb, and the "best" seems to be soem washing up liquid, a good dose of bleach and boiling water. Leave for overnight and it did seem to work. I would wrap it all in bubblewrap or similar to keep it hot as long as possible, things happen twice as fast for every 10 degree increase in temp so really helps.

westf27 - 1/9/25 at 12:25 PM

Dishwasher tablet and boiling water helped me.

adithorp - 1/9/25 at 05:10 PM

Dish washer tablet, hot water and, if it's really stubborn, add some pea gravel. Give it a good shake. Beware though, it could take as much shaking to get the gravel out if it's multi-chambered.

Also worth considering, if you know what it's from new ones are surprisingly cheap

[Edited on 1/9/25 by adithorp]

gremlin1234 - 1/9/25 at 07:24 PM

quote:
Originally posted by adithorp
Dish washer tablet, hot water and, if it's really stubborn, add some pea gravel. Give it a good shake. Beware though, it could take as much shaking to get the gravel out if it's multi-chambered.

Also worth considering, if you know what it's from new ones are surprisingly cheap

[Edited on 1/9/25 by adithorp]

but many new ones are of inferior quality

nick205 - 2/9/25 at 09:13 AM

quote:
Originally posted by gremlin1234
quote:
Originally posted by adithorp

Also worth considering, if you know what it's from new ones are surprisingly cheap

[Edited on 1/9/25 by adithorp]

but many new ones are of inferior quality



Have to say, that would be my choice (if you know what car it cam from).

After that, make sure to use the correct coolant type and mix.

And give it a change/rinse once a year as well.

Slater - 3/9/25 at 01:31 PM

I have my old "Polo" one which is fairly clean, can sell it for £15 + postage. It even comes with home made bracket to fit to a bulkhead.

Only issue is that I'm away working right now and not back till end of the month.

Let me know if your interested....

Here is a pic, I have since replaced it with an Ali one.


[img] Engine Bay
Engine Bay [/img]

ETA Here is another Pic

[img] Expansion Tank 3Sep25
Expansion Tank 3Sep25 [/img]

[Edited on 3-9-25 by Slater]

nick205 - 4/9/25 at 08:34 AM

^^^

Most VAG (VW, Seat, Skoda and so on) vehicles I've been under the bonnet of have these coolant tanks.

Not had any issues (discoloration) on the several that I've looked after (some 10+ years old). That said, the engines were unmodified and were filled with the OEM recommended coolants/ratios.