1989 Nissan Pathfinder Overheating

  • 1 POST
  • 3.0L
  • V6
  • 4WD
  • 205,000 MILES

I saw your answer to the guy with the 2002 Pathfinder. You put up a picture of his engine with the location of air bleeder valves. That picture did not look like my engine at all (V-6 3.0L 291[?]) Do you have a picture of the bleeder valve locations for the '89 V-6, or does mine have them? Thanks Ken M.

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Saturday, June 6th, 2015 AT 9:52 PM

1 Reply

  • 29,782 POSTS

Not all engines have bleeders for the cooling system, but more importantly, they're only needed after repairs have resulted in the need to refill the system. If nothing was done to the cooling system, and the engine just started overheating, bleeding isn't going to solve it. If there is air in there in that case, it came from a leaking cylinder head gasket. Combustion gases can pool under the thermostat and prevent it from opening. Thermostats have to be hit with hot liquid to open. Hot air won't do it.

Bleeders are almost always on the thermostat housing. Follow the upper radiator hose to that housing. If you don't see a bleeder screw there, you can also remove one of the coolant temperature sensors, or there may be a threaded plug near that housing. If you remove a temperature sensor, there can be three different kinds. If you have a temperature gauge on the dash, that will use a sensor with a single wire. You can unplug that anytime to remove it. The Engine Computer uses a two-wire sensor. If you need to unplug that one to remove it, do so with the ignition switch off. This isn't a big deal, but if the ignition switch is on, the computer will see when you unplug it and set a diagnostic fault code. That will just confuse a mechanic if he has to diagnose some other unrelated problem in the near future.

You might also find a temperature-controlled vacuum switch in the area. On newer cars you can set a fault code at certain times by unplugging those hoses, but that's not an issue on your car.

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Saturday, June 6th, 2015 AT 11:52 PM

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