Constant coolant loss

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by mstr33t, Apr 12, 2012.

  1. TimTom64b

    TimTom64b Epic Member 5+ Years 500 Posts ROTM Winner

    My 1997 2500HD with the vortec 35O has them... I had just replaced the intake gaskets last thanks giving... Myself. There are two ports on each head front and rear on both the drivers side and passengers side. Mine was leaking slowly between one of the intake ports and coolent the back of the block. Eventually it blew out to where it was leakinO on top of the intake. But then again what do I know.
  2. shibby2oo8

    shibby2oo8 Member 2 Years 100 Posts

    Thats a 5.7 gen 1 motor. The sbc/bbc (305,350,454,etc) are gen 1's, the LT's are gen 2 (LT1, LT4), the LS series are gen 3 including the truck engines, the ls series with DOD, displacement on demand are the gen 4 motors. Besides the 3 and 4's the motors are completely different design and parts. In this case his 4.8 gen 3 motor doesnt have intake coolant passages only small metal cross over tubes from the heads. Besides the throttle body lines pulling an intake on these doesnt open the coolant system.
  3. TimTom64b

    TimTom64b Epic Member 5+ Years 500 Posts ROTM Winner

    I really thought mine was the gen 3. Anyway I hope he finds a solution. Mine suffered from cooling loss for years... Before a full failure. I used alumaseal as I had thought possibly a cracked head. Good luck.
  4. shibby2oo8

    shibby2oo8 Member 2 Years 100 Posts

    Took me a while to get it down too. Unfortunatly leaking intake gaskets is the cause of failure for most 90's- early 00's gm engines. My grandma had a lumina van that they had to put a jasper engine in then she gave it to my cousin who ignored the intakes again and popped the head gaskets who gave it to me and I threw some 3.1 heads on the 3.4 and flipped it for a profit. If you overheat aluminum heads they will almost always crack. I sold it to a guy who uses the enormous dash as a shelf to deliver papers, he still has it.
  5. dbb06

    dbb06 Member

    I actually had a similar problem with my my dd car. I would drive for 2-3 weeks fine then notice my temp gauge slowly rising. I'd refill the radiator, and the process would repeat. I finally had a few days off work and decided to look into it. I found out the thermostat was sticking closed, so the coolant was basically boiling inside the engine. So check your thermostat.
  6. redvett

    redvett Rockstar 100 Posts

    Dex cool is not the problem its the acidity in the coolant from not changing the coolant. Do not change from a Dex cool based antifreeze as the aluminum components will degrade much quicker.
  7. Jimmeh

    Jimmeh Epic Member 5+ Years 500 Posts

    Quick question, and it may sound kind of dumb. For the last week or so, I noticed that every once in awhile I will get a antifreeze smell inside the cab of the truck through my vents when using the heat. My temp gauge stays where it's at so I am pretty confused. My fluid has actually stayed pretty consistant now that I think about it. I've added maybe a full gallon throughout the entire duration I've owned it (now a little over 3 years). But, I have no flushed the system since owning it either, and it now has 92,000 miles on it. Anyway, back to the original point: could this be a sticking thermostat? I always thought that normall if it would stick closed, the engine would overheat, and that open it would just be leaking like a siv....
  8. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Stuck closed will over heat the motor. Stuck open and the motor will not get to operating temp. Your coolant smell could be a small heater core leak.
  9. paracutin

    paracutin Rockstar 100 Posts


    10 chara

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