Bought 1989 Ranger 2.9L Temp gauge fluctuating alot, why?

Discussion in '1989 - 1992 Ford Ranger' started by mibson, Nov 11, 2009.

  1. mibson

    mibson New Member

    89 2.9L ranger. 97, 000 miles. I bought it recently and had a massive leak from the water pump. I had never done any work on a vehicle but decided its time to learn.

    I did drive about 4-5 miles with almost no rad fluid (by accident) before I noticed the leak - perhaps I fried the temp sending unit? It was negative 10 C that day (14 F), I hope there is no serious engine damage...

    Replaced water pump (after market prestone), thermostat (180F $8 aftermarket), replaced all hoses. Had to use Heli Coil from pervious owner stripping bolts. 300km on the road with no leaks. Then a drip leak in the rad started, used stop leak and it seems to have worked.

    Truck runs fine, heater works fine (perhaps a little cooler than normal - but still very warm).

    The temp gauge moves from cold up to the low end of normal and back to cold again, it does this over and over. What could be the problem?

    People on another form thought:
    1) cheep 180F stat
    2) temp sending unit broken.

    Thanks for any ideas.
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  3. 90RedRanger

    90RedRanger New Member

    Hi Mibson.
    It could be the radiator is clogged. The stop leak can work sometimes but it can clog the rad in some cases. I don't think it's the thermostat. The thing I would do next is to replace the temperature sending unit that controls the gauge. This is a lot cheaper than a radiator or other parts.
  4. preranger

    preranger New Member

    You can pressure test the radiator and it should tell you if the radiator is clogged. Also, is the check engine light on? It could be an electrical gremlin
  5. gdog1678

    gdog1678 rangerdanger

    ya, i would say air or clog in the radiator

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