Water leaking from the firewall

SOURCE: 98 pathfinder water pump

Chances are if you have a coolant leak right under the water pump, especially with engine running, the inner seal in the water pump is shot & the entire water pump will need to be replaced with a reman / new one. For the amount of hassle required to replace the seal it is worth the couple hundred bucks for the new pump.

There would definitely be overheating problems if the pump were not working at all. You will also have overheating problems present if there is low coolant, make sure the rad is topped up, with heater(s) on "Hot" inside & run the engine until it shows warm on the gauge. Make sure all of the belts are tight & pump looks like its spinning.

SOURCE: I have 1994 Nissan Altima 230K that overheats after a few miles.

you've answered your own question! You're cooling system has leaks possibly from your rad. You should have no leaks whatsoever.
I would also look to see if you have leaks anywhere else. Look under the car on the passenger side - see if you have leaks from the water pump. I would go to a radiator
repair shop. They will flush the system and check for leaks.
I wouldn't hang around or else you will damage your engine AND transmission. Which will be more money down the line.

SOURCE: Overheating engine

Hello shotmaker25...If you put Bars Leak in the cooling system and it plugged a hole in the radiator it's also plugging the the cores inside to some degree... A radiator shop should be able to diagnose a clog, if it exists. The rad can be removed and flow tested. A shop that has a hydrocarbon sniffer can also detect if combustion gasses are getting into the cooling system with a probe...The cooling system must be bleed and purged..if air is trapped in the system, your altima will overheat..If the catalytic converter is plugged, it will overheat... Make sure the cooling fans are working..they should cycle off and on.
Good luck...i hope this helps...please rate me a fixya.

SOURCE: I have a water hose leak and can't find where the end

Cooling system leak is misanderstending of what is leaking ?That it is you can fing by coolant vapoure or leake product like salt ,hose is moste likely must repair whitout replaising usin high temperature silicone .

SOURCE: Nissan Altima Water Leak

I also have a 2009 Nissan Altima and after sitting or driving in the rain the entire back floorboards are soaked. I took it in last year and supposedly they replaced a "plug". Unfortunately the repair was done at the end of the rainy season so everything seemed to be okay. Fast forward to this seasons first real rain and again soaked floorboards. I went back to the dealership very frustrated with the whole situation. This time they had had my car for 4days and I was told that the HVAC box was leaking due to a clogged line. The line was cleared and sealants used on certain areas. The service advisor is confident that this will take care of my problem. I'm not so confident since my HVAC system was not in use when the car was just sitting there filling up with water. Wish me luck. I am curious how many 2009 Altima's are having this problem and if Nissan is just trying to avoid some sort of recall notification. Very dissapointed 1st time Nissan owner.