My 2001 Nissan Frontier 4x4 (6 cyl) is leaking coolant. the coolant is dripping down to the back of the engine and off of the transmission housing. a friend told me that water pumps will do that if they are about to go out, but I have no idea how to check that and no idea of where to see the pump or for that matter what it looks like. Any help would be most appreciated

your radiator coolant might be leaking into transmission . big recall on 05 frontier models. check to see if transmission fluid is a milky color.

Nissan Frontier, Xterra 1998-05
Thermostat Removal & Installation - 3.3L Engine



Fig. Thermostat assembly and related components-3.3L engine (clock over pic for zoom)

NOTE Never remove the radiator cap when the engine is hot. Serious burns could occur from high-pressure engine coolant escaping from the radiator.

1. Be sure the engine is cold.
2. Disconnect the negative battery cable.
3. Drain the coolant. Properly disposed of used coolant.
4. Remove the upper and lower radiator hoses. Remove the fan shroud.
5. Remove the drive belts and the pulley bracket.
6. Remove the water inlet retaining bolts.
7. Remove the water inlet and the thermostat.
   

To install:

1. Installation is the reverse of the removal procedure.
2. Be sure to apply a continuous bead of the proper grade and type RTV sealant to the housing.
3. Install the thermostat with the jiggle valve or air bleeder at the upper side.
   
   
   Fig. Thermostat jiggle valve/air bleeder location-3.3L engine
   
4. Be sure to refill the cooling using the proper grade and type engine coolant.
5. Start the engine and check for leaks.
6. Start the engine and allow it to reach operation temperature. Recheck the coolant level, fill as required.

Hope helps (remmeber rated this).

Go to a different dealer. The dealer should know what is wrong with the vehicle by the codes. Don't let them keep guessing what is wrong and having you replace random parts.

Mazie, Slater, Katz & Freeman, LLC is putting together a class action lawsuit against Nissan Motor Company related to issues where a leak from the radiator into the transmission is causing radiator and transmission failure. This problem is prevalent on several 2005, 2006 Nissan Frontier, Xterra, Pathfinder models. My vehicle is a 2006 Nissan Frontier. Please share your information so Nissan will have to accept responsibility for their defect. Go to www.transmission-lawsuit.com to share your details.

how much oil do you put in in a weeks time?

If transmission fluid is dripping off the bellhousing your torque converter seal is leaking or your transmission pump seal is leaking. Chances are the torque converter seal is leaking since the torque converter is spinning on it any time the engine is turning, the pump seal dosen't move it just keeps fluid inside the transmission. Even though it leaks with or without the engine running I'm willing to bet if you got underneath it with the engine running you will see it leaks more with the engine running. Now if either seal is leaking it will require the engine to be removed from the transmission to get to the seal. Sorry but this isn't going to be a cheap quick fix.

coolant leak may be coming from intake manifold gaskets,4.3 is notorius for leaking coolant from behind the mainfold in those years

Two very likely sources for engine oil. You could have a valve cover leaking or a rear main seal. The best way to check is to trace the source of the oil. This requires a very thorough steam cleaning to remove all the old oil. Place an oil dye pack in the oil (about 3.50 at Napa and other parts stores). Run the engine for about 15 minutes and use a blacklight source and a mirror to check the back of the engine below the valve covers and closest to the firewall. Check out how the fresh oil floureces in the blacklight source by checking your dipstick for the color of the glow. If the back of the engine is dry and clean and your puddle is still glowing from between the engine and the transmission, you have a rear main seal and the transmission will need to be removed to change the seal. Spend the time on the diagnosis before you spend the money.

tie the clamp

Sounds like either the water pump or the thermostat housing. The water pump has a small hole in the bottom where the shaft comes through, when the water pump gets worn it will leak here so you know to replace the pump. The thermostat housing will be at the motor end of the upper radiator hose where it attaches to the motor. Hope this helps.