98" 454 and the disappearing Water Trick

Discussion in 'GM Powertrain' started by udderchaos, Feb 5, 2008.

  1. udderchaos

    udderchaos Rockstar

    Ok, I have a 7.4 in a 98 K2500 Sub, with 225,xxx miles. I am losing water somewhere. It isn't consistant at all. I checked the fluids last Friday, before I took off, and they were fine. I check it this afternoon, and it's about three quarts low on coolant..!! Local shop said it had a "minute" leak at the intake. I have been chasing this leak for....since I got home in Nov. It doesn't leak alot, til now. But, where does it go..??? I had a puddle under the Sub, but not THAT much...( It has rained) Any ideas what it could be??

    Thanks, Bill

    P.S. This truck has served me well. It doesn't burn oil, has plenty of power, just has the usual maintanance stuff a 225xxx truck would have....
  2. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Sounds like the intake gasket may be leaking into an intake port in the head and getting burned in the cylinder. Might check the spark plugs and see if one or more are a different color.
  3. 84fiero123

    84fiero123 Epic Member 5+ Years 1000 Posts Platinum Contributor

    I second that one.
  4. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Yes intake leaks are common. I use a cooling system leak tester that I bought at NAPA to t/s those little leaks. Right now I've got a leak on a heater hose at the back of the block. With all that's going on right now, I'm just topping the coolant off every couple of days. When warmer weather gets here, I dive under the hood and fix it permanently.
  5. collinsperformance

    collinsperformance Epic Member 5+ Years 500 Posts

    one other place that gets over looked real often is the raditor cap. the system get warm and the cap allows some heat to escape and as this happens it will take some water or coolent vapor with it. after some driving the level will go down. pull the cap and look at the gaskets if not dry or cracked or bad looking you can coat it with some grease or vassiline and see if this helps if so replace with a new cap and coat the seal so it will serve you for a long time......mike
  6. blue whale

    blue whale New Member

    Magic Mystery Leak

    If you dont SMELL coolant I would lean toward gaskets as suggested. My 01 sub had same issue WITH smell and quickly found Ye old weep hole on pump with dribble .

    Good Luck
  7. udderchaos

    udderchaos Rockstar

    Thanks All,

    I sent the Subby back to the shop that we have look at it. They found a couple of things that were leaking. The shop told me the intake gasket was leaking, but very minute. I told them if the intake has to come off, I'll change the timing chain/ cam, and do a port match on the intake. They weren't real enthused about hearing that. The radiator was replaced about four months ago, along with the cap. So, the cap was tested too, not real happy about doing that either.Just make me happy kids. The water pump was checked too.... I'm just waiting for the heater core to start leaking...!!!!!!

    I noticed last night, I have a small "spot" under the passenger side wheel well area...figures...

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