hi everyone,
i'm planning on changing the water pump in my w123 om617 on saturday. i ordered the graf model part from pelican.
i've been looking into what i need to do, and want to make sure i have it right, and what else to look out for, as i'm pretty sure there's going to be something i'm missing.

i'm changing the water pump because my coolant has leaked all out. i pulled over and refilled it with whatever coolant i was sold at a gas station for my previous toyota, and brought it to a local mechanic, not a german car specialist. they said 100% the water pump needs replacing.

while waiting for the water pump to come, i've been driving locally with distilled water as coolant, refilling every 30 min as it drips out, my temporary solution.

the best instructions i could find were right here on pelican:
Mercedes-Benz W123 300TD Wagon Technical Articles (1977 - 1985) - Pelican Parts
for taking the fan out, alternator belt, and then water pump

my Qs are:
1) i saw somewhere that sealant should be used on the water pump gasket, but it’s not mentioned on the pelican article, is it necessary?

2) how can one tell if the cap for the coolant overflow tank needs replacing?

3) is 11L / 2.9 gallon of coolant accurate? when i’m using distilled water, it gets full in a gallon or less, so if 11L is right, i’ll have to make sure to drain all the remaining water, i thought it was completely leaking out. i plan to use either MB or zerex G05

thanks!

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w123
1985 300D turbo sept 2015 - present
1985 300TD turbo oct 2023 - present
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