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The windshield washer fluid tank on my Toyota Corolla has a C-shaped crack in the bottom. I removed the tank and drained it. Is there a reliable way to patch/fix this without having to buy a new tank? (I'm thinking of trying to patch the crack with silicone caulk.)

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up vote 9 down vote accepted

I fixed a leak in my coolant tank (which is the exact same plastic) using a few strips of plastic* cut from a spray bottle I bought at a hardware store. You can either use a heat gun or a soldering iron to melt the plastic into place. Just be careful of burning the plastic.

This video is a good guide. Even though it's a much larger tank, the technique is exactly the same.

*It's technically not plastic, but rather polyethylene.

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I fixed it! Thanks. I used strips of milk carton because it's the only polyethylene I have. Mine didn't turn out near as pretty as the one in the video. In fact, it looks more like a spot of leprosy. But no one is going to see it anyway! – Stainsor Jan 25 '14 at 4:47
Mine didn't exactly look very good either ;) I'm glad it worked out for you. – Juann Strauss Jan 25 '14 at 10:02

It's definitely possible. My choice for a repair like this would be JB Weld, but I would think lots of products would do fine, though I'd be skeptical of any kind of caulk that's not going to bond tightly to the plastic.

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I would probably not use JB Weld, only because it becomes hard while the tank is still slightly flexible. There are plenty of flexible plastic sealants out there for use. Your general theory of repair is sound, though. – Pᴀᴜʟsᴛᴇʀ2 Jan 13 '14 at 11:32
Thanks for the comment. – R.. Jan 13 '14 at 12:38
As I was melting the plastic on I kept thinking I should have just used JB Weld. It would have been quicker, easier, and cheaper than buying a heat gun. (But half the reason I didn't is because I wanted to buy a heat gun!) The plastic is a little flexible, but I think it's stiff enough that JB Weld would have worked. Also, I think the crack was caused by road debris being flung up into the bottom of the tank. A hard covering might give it a little added protection for next time. – Stainsor Jan 25 '14 at 4:50
I tried using JB Weld to repair some other plastic item on this car and the JB Weld didn't hold. Apparently it doesn't bond to plastic very well. – Stainsor 11 hours ago

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