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88 YJ 4.2L 6 cyl 258 overheating

Discussion in 'Wrangler YJ (1986-1995)' started by dpgraves, Mar 23, 2019.

  1. Mar 23, 2019 at 10:06 AM
    #1
    dpgraves

    dpgraves [OP] New Member

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    I have recently had an issue with my YJ overheating when driving. Recent maintenance includes replacing valve cover and gasket and replacing spark plugs and wires. Correct wires were verified on changing the spark plug wires by replacing one at a time. The oil pressure gauge indicates high pressure when it overheats. No major leaks for oil or coolant. Oil and coolant levels are within range. I tried to bleed the coolant by parking on a steep slope and revving the engine with the radiator cap open. The coolant level was right up to the cap and did not lower as the engine was revved. As it was idling with a high engine temp indicated the valve cover and top of the engine did not feel hot to the touch. However, when driving at the high temp, smoke lightly came into the car.

    Any suggestions are appreciated! Also, I'll admit I'm kinda new to the game.
     
  2. Mar 23, 2019 at 1:14 PM
    #2
    aggrex

    aggrex Well-Known Member

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    Welcome @dpgraves ....suspect the thermostat?
     
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  3. Mar 23, 2019 at 1:24 PM
    #3
    dpgraves

    dpgraves [OP] New Member

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    @aggrex that was my suspicion as well, replaced and letting sealant set before adding coolant and giving her another go. Thanks for the response will update!
     
  4. Mar 23, 2019 at 6:53 PM
    #4
    Jim Beam

    Jim Beam Well-Known Member

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    If you recently changed coolant, there could be an air pocket in the cooling system causing the problem. A bad fan clutch can cause your problem also, along with what has been suggested.
     
    JKBob 25 likes this.
  5. Mar 23, 2019 at 7:44 PM
    #5
    dpgraves

    dpgraves [OP] New Member

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    Had a leak on the bottom set screw of the thermostat housing, working through that one now
     
  6. Mar 24, 2019 at 9:18 AM
    #6
    Jim Beam

    Jim Beam Well-Known Member

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    So you overheated due to loss of coolant?
     
  7. Mar 24, 2019 at 12:08 PM
    #7
    dpgraves

    dpgraves [OP] New Member

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    @Jim Beam it wasn’t leaking before I replaced the thermostat. I am assuming/hoping I did not wait long enough for the sealant to set before adding in coolant.
     
  8. Mar 24, 2019 at 5:28 PM
    #8
    Jim Beam

    Jim Beam Well-Known Member

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    Go a bit anxious huh? Hopefully everything will be fine when you reseal it.
     
  9. Mar 24, 2019 at 6:23 PM
    #9
    JKBob 25

    JKBob 25 Well-Known Member

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    @dpgraves. A quick test. Once you get everything sealed up and running at operating temps. Squeeze the upper and lower radiator hoses. They should both be hot and hard to squeeze. That will assure you coolant is flowing. Should be no blockages. Air pockets are another issue.
     
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