My car overheating because water pump failed. change the water pump and replace gasket. the sensor between two cylinders was changed because it burnt. the car cant start again

If your 2004 Infiniti G35 is still overheating after replacing the thermostat and cooling sensor, there may be a few other issues that could be causing the problem:

1. Radiator blockage: The radiator may be blocked or clogged, preventing the coolant from flowing through it properly. This can cause the engine to overheat. To check for a blockage, visually inspect the radiator for any obstructions or debris, and flush the radiator to clear out any buildup.
2. Water pump failure: The water pump circulates the coolant through the engine and radiator. If the water pump fails, the coolant will not circulate properly, and the engine can overheat. Check the water pump for any signs of damage or wear, and replace it if necessary.
3. Fan clutch or electric fan failure: The fan clutch or electric fan is responsible for cooling the radiator when the car is idling or driving slowly. If the fan clutch or electric fan fails, the engine can overheat when the car is not moving. Check the fan clutch or electric fan for any signs of damage or wear, and replace it if necessary.
4. Head gasket failure: If the head gasket is blown, coolant can leak into the engine cylinders, causing overheating and other problems. Check the head gasket for any signs of damage or wear, and replace it if necessary.

As for the no heat issue, it's possible that the overheating has caused damage to the heater core or other components. It's also possible that there is air trapped in the cooling system, preventing the coolant from flowing properly through the heater core. Bleeding the cooling system may resolve the issue.

Never use a gasket cement for a cylinder head gasket, it will fail!
Water pump is the obvious fault if there is no water in the oil or oil in the water.

Have you replaced the intake manifold gaskets? These engines have a history of leaking intake manifold gaskets. Water leaks into the intake and is burned off in the cylinders. If the engine overheats enough times, you will eventually blow the head gaskets.

Start by performing a compression check to make sure you haven't blown the head gaskets. Then make sure the car is really overheating (i.e. check the temperature of the engine with a infrared thermometer (they are cheap at Harbor Freight).

If it is really overheating, and you've really changed everything else, you need to change the intake manifold gaskets. Be sure to get the improved gaskets from the parts store (they have a metal core with rubber coating).

do a compression check on those 2 cylinders to rule out head gasket, check the new plugs you installed to see if they got fouled out, it is possible some anti-freeze may be leaking into those cylinders from the intake gasket.
1998 uses dex cool anti-freeze and it is known to eat away and corrode the gaskets.
the only good way to use dex cool is to mix precisely 50/50 and use distilled water.
switching to the green can cause water pump damage since they are designed for the lubricant in the dex cool.i mention the anti-freeze because a lot of people will change the gaskets and run the green only to have a failing water pump not long after, if you decide to switch make sure you replace the pump.

If one of the head gaskets are leaking a cylinder compression check will reveal it and the cylinder it is on. The weird temperature reading could be a bad sensor or wiring to the sensor that is shorted to ground.

Then the problem is the water pump or a cracked Head, blown head gasket or cracked cylinder wall causing over pressure in the cooling system. Replace the water pump first then consider the other problems. If you do a compression check and have compression on all cylinders but extremely high compression on 1 or 2 then the problem is the Head gasket, head or Cylinder wall being cracked.

Overheating is not always caused by a bad water pump or bad engine firing timing.

The most common causes are:

• faulty radiator cap: steam/water will be escaping from the caps when engine is hot or oveflow tank overflows or empty!
  
• crack cylinder head gasket: check when engine is cold thru radiator cap hole for milky oil in water radiator or large bubbles in radiator water after starting engine. Also check if water steam comes out of exhaust.
  
• cylinder head itself: same symtoms as for gasket above.

Hope it helps you find your problems.

it could be the head gasket blown out...there is a test for this,, i call it a "sniffer test"??? what happens is you **** out some rad water and tip in a chemical that picks up any hydrocarbons in the water,,,and if the cylinder head gasket is leaking there will be hydrocardons in this water if none are found its not the gasket,,,so check the rad is clear and not blocked and you dont have an air lock in the water jaket

it's quite possible that the head gasket is blown and it's allowing water to enter one of the cylinders and that's a good possibility for the white smoke. It may be that before the water pump was changed that it overheated and allowed the head to blow a gasket.

hi, if you are changing the head gasket then it may be worth checking the water pump and thermostat as it could have been one of these that failed causing it to over heat and then blown the head gasket so check the water pump and thermostat once you have the cylinder head off.

You may need the head checking to see if it has been warped but this is unlikely on this make of vehicle.

Once you have done the gasket make sure that when you fill the coolant up you only trickle the water in to prevent any air lock as this will cause it to over heat again, check for any bleed screws on the coolant system to let the air out whilst filling the coolant up,

Its best you check in the workshop manual for these as their may not be none as it could be self bleed system.

It also worth checking if the head bolts need changing as they do stretch and can cause the gasket not to seal properly so replacing these may be a good idea.

Let me know how you get on or if you need further assistance ok.

ps what makes you think the head gasket has gone??