there is not a solid way to patch the tank, the only way you can solve your problem is replace it!
Could be several reasons, need to know aprox where it is leaking from.
Need to know the location of the vacuum leak in order to answer this.
no get rid of it they usually leak
It is probably the oil cooler lines.
Head gasket or cracked head. Mo
Normal leak points that are hard to see are inside the rear drums, along the frame, and into the brake booster.Normal leak points that are hard to see are inside the rear drums, along the frame, and into the brake booster.
Check for vacuum leak
I have a leak on my drive shaft left front 2000 cheve Blazer I would like to replace the whole unit
Check the heater core your water could be antifreeze leaking from it. Either broken connection where hoses connect or bad core itself located inside dash.
small evap leak, check the fuel cap, if it is not loose, replace it.
when i turn my truck off water leaks from the bottom all the time
You have a small "EVAP" leak. Start with replacing the fuel cap.