If the container is to be used for food, cracks and leaks make it unusable because any of the repair materials and/or the crack could become havens for bacteria.
Silicone, or JB weld. For plastic pools or buckets, shoo goo works wonderfully to fill the crack and support the weak spot.
The fix is replacing the leaking part.
You can't. EPA and the government requires a gas tank to be replaced if it is leaking or cracked.
If it's cracked, it might be made of fiberglass, or plastic. Fiberglass patch or two part epoxy.
Yes! if you have a cracked head chances are your oil and coolant are mixing together and coolant and or oil is leaking out causing the vehicle to overheat... if you have a cracked head fix it! do not drive the vehicle
your heater core is probably made of plastic and has finally cracked like they all do. See the dealer or a professional like myself.
More information needed. Is it visible, is it underground, is is plastic, is it metal pipe - -
If you mean the plastic overflow tank, replace it. If you mean the plastic tanks on either side of the radiator core, replace the radiator.
You can replace it. Or you get a plastic tank fix kit in AutoZone or Advance Auto Parts.
you can heat the cracked area to a plastic state with a blow torch or get it refunded
If your engine is visibly leaking oil, you should remove that cover and try to find the source of the leak. But this is not something a typical do-it-yourself mechanic can fix, its possibly you will need new gaskets or worse (such as cylinder rebuild, or worst case replacement of a cracked engine).
First find where the 99 Rodeo is leaking fuel from. Check for loose or cracked fuel lines. The leak needs to be found before driving the vehicle, as the leak could cause a fire.
I am going to presume you mean the windscreen washer. The best fix is to just replace either one that is leaking. The "bottle" is usually made of plastic and is pretty hard to repair with any certainty that it will not leak again.