Coolant Expansion Tank Repair

[DavidOliver]

Just a thought.
If you can clean the inside of rust a bit, you can use a resin coating inside to form a continuous bag.
After all, the water leak comes from the inside so plugging from the inside is better.

Dave the cog.

[Pete Boole]

+1 for JB Weld - buy the one that's not quick setting - it's the strongest. Use it to bond on a patch as Bash suggested rather than just blobbing it on. It's absolutely essential that both parts are grease-free and keyed. Maybe use a big Jubilee clip to keep it in place while it sets.

Pete

[richardw]

I would consider moving to Evans Waterless Coolant to reduce stress on cooling system components. As the boiling point is 180 degrees, there is little or no pressure in the system, meaning that fewer leaks will develop and when they do they will tend to be gradual rather than catastrophic. As a side benefit, it is non-corrosive and will be kinder to the water pump than standard coolant. It is expensive and you have to flush the system first with a special flush, but worth it I think. I’ve had it in my car for several years.

Cheers, Richard

[Marten]

+1 for JB Weld - buy the one that's not quick setting - it's the strongest.

I'd go for (quick setting) Fe Weld , it looks fairly easy*) to replicate if you can reuse the spouts.

*) metal fabricating workshop required

[rbgosling]

Well, it seems my repair didn't last that long. The rust streak on the outside tells an unmistakable story:



To be fair, the inside of the tank is horrible, so it had to go.

So, I've admitted defeat, and dropped £222 (inc. VAT) on a shiny new aluminium one from SJs.



Looks good, no rust (and never will be), and lighter! Didn't come with a level sensor, but it did have the hole and a new grommet so I just pulled the sensor out of the old tank and pushed it into the new one. Only hitch was that tab they welded on for the earth was way too chunky for the spade connector, so instead I drilled and tapped a hole in the tab and crimped a ring connector instead of the spade, which could be screwed into said hole:

[Pete Boole]

What's the other tab that appears to be welded to the end of the tank?

Pete

[rbgosling]

What's the other tab that appears to be welded to the end of the tank?

Pete

Just appears to be a flat plate, welded only on the outer edge. No idea what its purpose is. The original tank had one too (welded on both sides - just pulled it out of the recycling to check!).