Multiple issues, need help diagnosing 4.7 V8

Discussion in '120-Series Toyotas' started by gthoman, Aug 10, 2018 at 9:52 PM.

  1. gthoman

    gthoman

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    Hello All,

    I have a 2003 GX470(245,000 miles) V8 4.7L and last weekend all my problems started. I was towing the boat home when all of a sudden the CEL/VSC lights came on and smoke pouring out under the hood. Pulled over, opened the hood and the top radiator hose had come off! I had some water in the car and was only about 8 miles from home so filled it up, clamped the hose back on and started again. Only made it about a mile and smoke out of the hood again. Both times I was looking at the temp gauge and it was sitting between hot/cold(normal). I had the car towed to my house and checked the codes, it had a P0117. Someone suggested that it might be the thermostat, so I replaced the thermostat and while pouring the new coolant in I noticed dripping coming from under the top radiator hose, the radiator had a crack in it. So, I then ordered a new radiator and replaced it, hoping that was the problem. Filled the car with fluid/cleared the codes and started it up. It seemed to have a hard time starting(turning over several times before starting), but it did start. I had the radiator cap open and the car to fill with coolant. I was filling up the coolant as it ran, but seemed to start boiling and overflow from the overflow. The idle was rough(not really rough, but lack of power), tried to put it in gear and it turned off. I checked the codes and this time it had P0300, P0302, P0303, P0305 and P0306(bunch of misfires). I've read it could be timing belt, head gasket, water pump?? Any help would be GREATLY appreciated.
     
  2. Vlad

    Vlad The Impaler SILVER Star

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    Sounds like the timing belt could have let go. That would explain the multiple misfires. The coolant issue...the TB is RIGHT behind the water pump, so you could have a lot going on. 2003 is good news. Non-interference motor. You can tear into it, replace the timing belt, water pump, hoses, and refresh the coil packs and plugs and catch up on maintenance.
     
  3. gthoman

    gthoman

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    Thanks Dan, I was thinking this might be the case, but thought this was an interference motor. Good to know that its not. Thanks Again!!
     
  4. Vlad

    Vlad The Impaler SILVER Star

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    05+ are. The subtle difference of 03-04 and 05+ are the timing and vvti. It causes all sorts of confusion. Hence why you can SC an 03-04 but can't in the 05+.
     
  5. HomersCanyonero

    HomersCanyonero

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    That’s great advice from Dan. I had a independent mechanic replace all my cooling parts on my 2003 including radiator, big hoses, cap, thermostat, water pump, and timing belt.

    I got all the parts/coolant myself and only cost about $550 including tax and shipping. All were done together at the same time. Labor was $500.

    The 2003 GX470 4.7 V8 seems to run quieter than the V8 on my 2008 LS460. Not sure why but my GX470 engine is super quiet.

    By the way, how hard is it to get to the coil packs? That’s one thing I haven’t done
     
  6. Vlad

    Vlad The Impaler SILVER Star

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    Coil packs are simple. They are RIGHT there in the open. Plug and play.
     
  7. LaserNomad

    LaserNomad

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    I dont want to think about how much a supercharger would kill the mileage. You could take it to a pro and have them figure it out and then fix it your self... I would only do this if it was a fun car and not a DD.
     
  8. half k cruiser

    half k cruiser

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    Hmm, so it built up enough pressure to blow the hose off ( not blow a hole in the actual hose ) ? Then you develop a bad radiator. Sounds like a significant overpressure on your cooling system. That can be caused by either a bad radiator cap, or exhaust gasses entering the cooling system.
     
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