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GMC engine repair questions and answers

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  • GMC97
    GMC97 - 1997 GMC C1500 Suburban - Engine - 4 hours ago
    How do I test to see if I have a bad head gasket?
    Pretty sure it's bad but want to make sure , and can it be driven temporarily until I can afford to have it fixed without damaging the engine more? Thanks for any info.
     
    • GT500Knights
      12/19/2014 GT500Knights
      1. Remove radiator cap (when not hot). Have a helper crank over the engine. If you see bubbles submerging, or coolant splashing out, most likely head gasket.
      2. Check color and smell of coolant and oil. Coolant should have no oil smell, and oil should have no coolant or sweet smell. If color of coolant is an oily color, suspect head gasket.
      3. Compression test. All cylinders should be within 15-20 psi of each other.
      4. Gas test. You can buy these special tests at the auto parts store. They test for hydrocarbons (raw gas) in coolant.
    • Teddy B
      4 hours ago Teddy B
      You can not drive it at all,common sense

      It will loose coolant,overheat & kiss the motor goodby

      Use a Combustion Gas Leak Tester or Exhaust Gas Anylzer

      I would just have a repair shop do those tests for you

      You can have a head or gasket problem & not find it
      with compression or cylinder leak down test

      Do all the other suggested things as well

      Look at engine temps- cat temps- if in the data & fuel trim

      Use whatever tools or info you can,in the end you will have
      to take it apart most likely if coolant disappears
  • krashGMC
    krashGMC - 1999 GMC Yukon - Engine - 12/18/2014
    Truck will start in early morning run perfect, after being parked for longer than 10 minutes truck won't start
    I have a 1999 GMC YUKON 5.7 4x4 Truck runs great!! Perfect, no misfires. It will start perfect every morning even in the cold. But the next time I have to start it it takes 15-20 minutes of turning over before it starts???
     
    • Teddy B
      12/18/2014 Teddy B
      You checked for fuel pressure at the motor, with a gauge, to see if
      it holds pressure before you try & start it?
  • GMC97
    GMC97 - 1997 GMC C1500 Suburban - Engine - 12/18/2014
    Fixed heater hose and noticed what looks like oil in my coolant. Drained , flushed and refilled. Now it want to run hot?
    I think it may be a head gasket, my brother in law has been a mechanic for years and asked what the oil looked like when I checked it and the oil was clean . He said to drain it and flush it and it actually can be driven temporarily if needed with a bad head gasket ...
     
    • Teddy B
      12/18/2014 Teddy B
      Head Gasket like you were told

      Why did your brother in law not do the testing for a head gasket ?
      Teddy B
      12/18/2014 GMC97
      It was just a brief conversation over the phone, I was really hoping that wasn't what it was. If it isn't getting in the oil is it drivable until I can get it fixed or will it just keep trying to overheat? What's your guess on the cost of repairing? Thankyou for the information.
  • Rance
    Rance - 1998 GMC C1500 - Engine - 12/16/2014
    No Spark condition on 4,3 liter engine
    driving home engine started miss-firing . would not start the next morning. NO SPARK at COIL. so far NEW Parts are , Complete distributor assembly, ICM, CPS and COIL. All 4 parts for a GM engine to FIRE. Can the ECM cause a no spark at the coil.checked Ignition ...
     
    0 answer
  • Raymond Duheme
    Raymond Duheme - 2002 GMC T7500 - Engine - 12/16/2014
    Truck idles and runs for short distance and then no power goes back to idle
    150,000 miles cold or warm same more frequently now drive 5 miles 4 days ago waiting for a mechanic to fix changed fuel filter no different engine check light cam on and said check engine soon no
     
    0 answer
  • Curtis
    Curtis - 2006 GMC Sierra 1500 - Engine - 12/15/2014
    Coolant has leaked into the engine after repair
    Had an oil leak. Shop replaced my "oil cooler lines to pan Gasket". Within a couple days I had coolant in the engine. Are the problems related?
     
    • Teddy B
      12/15/2014 Teddy B
      Have to talk to the shop that did the work

      We have no way to know what was done
      Teddy B
      12/16/2014 Curtis
      I had an oil leak. They replaced the part in quotes. Within 3-4 days I had antifreeze in the engine. What I am wondering is IF replacing that part could have introduced coolant into the engine.
  • Curtis
    Curtis - 2006 GMC Sierra 1500 - Engine - 12/15/2014
    Coolant has leaked into the engine after repair
    Had an oil leak. Shop replaced my "oil cooler lines to pan Gasket". Within a couple days I had coolant in the engine. Are the problems related?
     
    0 answer
  • Pat
    Pat - 2003 GMC Sonoma - Engine - 12/8/2014
    Truck will start and run for a few days, then die. Brought to mechanic. They said it was fuel pump. Replaced it.
    Worked for few days and died again. Brought bak. Said it was battery. Replaced it. Ran a few days and died. Brought to different mechanic. They said it was a faulty anti theft device. Bypassed it and truck started right up. Gas gauge not reading. Brought back ...
     
    0 answer
  • richard
    richard - 2008 GMC Sierra 1500 - Engine - 12/8/2014
    Cruise control stopped working . fan stops working when driving on hwy have to reset with disconnection batterie
    cruise control went out slowly until it stopped working , when driving on hwy the fan will stop working until I reset by disconnecting battery ,inside truck readings check tire psi, change oil, trip miles, etc. in a loop. all these went out slowly , only the fan ...
     
    0 answer
  • richard
    richard - 2008 GMC Sierra 1500 - Engine - 12/8/2014
    Cruise control stopped working . fan stops working when driving on hwy have to reset with disconnection batterie
    cruise control went out slowly until it stopped working , when driving on hwy the fan will stop working until I reset by disconnecting battery ,inside truck readings check tire psi, change oil, trip miles, etc. in a loop. all these went out slowly , only the fan ...
     
    0 answer
  • trskinsfan
    trskinsfan - 2003 GMC Safari - Engine - 12/8/2014
    Heater does not work.
    Van has 211,000 miles on it. I replaced 2 vacuum lines to the heater valves. Still no heat. This weekend I replaced both heater valves, (front & back), and replaced the thermostat, topped off the coolant. Still no heat!! HELP!!!
     
    • jdl
      12/8/2014 jdl
      Does the engine reach normal operating temp? Are the heater hoses, hot? Can you check coolant flow through heater core? Does the heater blower motor work? If the hvac actuators are vacuum operated, did you check for vacuum source?
      jdl
      12/12/2014 trskinsfan
      Engine reaches operating temp, heater hoses are hot, blower motor works, and I have vacuum. Will double check the coolant flow through the heater core and check back.
  • trskinsfan
    trskinsfan - 2003 GMC Safari - Engine - 12/8/2014
    I have no heat whatsoever, not even warm!
    The van has 211,00o miles on it. Last weekend I replaced 2 vacuum lines, (to the heater valves), that were bad. Still no heat! This past weekend I replaced both heater valves, (front & back) and replaced the thermostat. Topped off the coolant let it heat up to temp. ...
     
    0 answer
  • soul
    soul - 2012 GMC Sierra 1500 - Engine - 12/4/2014
    Codes p0430
    engine light on
     
    • CVO
      12/4/2014 CVO
      P0430

      Oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs)

      The catalytic converter is no longer functioning properly
      An oxygen sensor is not reading (functioning) properly
      There is an exhaust leak.
  • krashGMC
    krashGMC - 1999 GMC Yukon - Engine - 12/4/2014
    99 GMC Yukon problem is starting up, after it starts it runs perfect.
    We have replaced the fuel filter replace the spark plugs replaced the coil pack put fuel system cleaner and injection system cleaner replace the crank shaft positioning sensor and also check the fuel pressure which the reading is fine when truck was on and off. ...
     
    0 answer
  • soul
    soul - 2012 GMC Sierra 1500 - Engine - 12/4/2014
    Engine codes
    engine
     
    0 answer