99 Chevy Coolant Leaking.... **SOLVED

Discussion in 'GM Powertrain' started by Howie, Jan 2, 2009.

  1. Howie

    Howie Rockstar

    Hey all having a doozy of a time with my new to me truck.

    Veh Charactoristics

    Year - 1999
    Make -Chev
    Model - C3500 (NOT HD) Crew Cab, Long Box
    Engine - 5.7L Vortec (L31)
    Trans - 4 Sp Auto W OD (Not sure on specific number)
    Rear end - 14 bolt (4.10)

    History - Noticed coolant was down slightly when purchased, topped off rad and tank. Noticed clip that holds the hose that connects the top of the radiator neck to the coolant recovery bottle missing. Level continued to decrease.

    Truck has had numberous leaks from a year in storage. Transmission pan gasket, power steering input line leaking at fitting.

    Problem - On way home from a short jaunt, tempurature shot up from 100'c (mid way) to slightly over 3/4. Shut truck down and pulled over in neutral. Noticed faint steam coming from:

    If you have the hood open and are facing the engine bay, the right hand, back corner of the block, way down the firewall. Not much visibility back there.

    I crawled underneath, after letting the truck cool down for a while. Coolant is noticed all over the power steering pump, making it look sopping wet. The cradle (huge bar that the engine sits on, and goes from frame rail to rail [crossmember?]) is also soaked. Oil pan is dry. Flywheel cover has a trace dribble on it.

    Checked coolant in radiator, which is down 1/4 way now. Coolant in recovery tank is at normal level. restarted truck, upper radiator hose colapsed.

    Went home and parked for a few hours, fearing the intake manifold gaskets may be shot. Oddly enough, they appear dry from what I can see, No sludge in radiator, or engine oil. Only thing that seems to be sopping wet is the power steering pump, but visable drops of coolant are seen on the steering bar (pitman arm crossbar), and crossmember.

    Im real confused guys.. I moved the truck, but no drips of coolant.. Its like I have coolant leaking from my power steering pump only.. Im really confused.. At first I thought it might be the intakes, but no cappachino, no odd coolant, no tailpipe smoke.. What should I be looking for? Its like my power steering pump decided to leak coolant..
    Last edited by a moderator: Jan 6, 2009
  2. oOcornflakeOo

    oOcornflakeOo Rockstar

    I'm no expert but if the radiator hose on the top (which I assume is going back into the top of the radiator) has collapsed, it is possible that your thermostat has locked up which should be on the other end of that top radiator hose. now you said that its a 3500 so I'm guessing its a diesel? idk if coolant plumbing is any different on diesels from gasoline engines.. but if in fact the thermostat has locked up, then that could explain why it seems you're leaking radiator fluid everywhere. by the thermostat locking up, extreme pressure from the boiling coolant (which shouldn't boil though it might have depending on the coolant mixture) can cause leaks around ring clamps and such. when the hose rips around those clamps from built up pressure, it sometimes will spray like a high pressured piss stream and get all over the engine bay (thus tricking you into thinking there are leaks coming from places they shouldn't). when your truck over heated, did you hear gurgling after you pulled over and checked the engine? and when you saw the "steam," did it smell like coolant? what did the coolant consist of.. 50% water 50% coolant or straight coolant? I hope you can recall this info cause it will help to diagnose your issue. I have had thermostats lock up on me on many vehicles (only once with a chevy) and generally, they're rather cheap. the collapsed top radiator hose says that coolant isn't getting passed (at least) the thermostat so check that out before anything else. try to make sure you answer all of those Questions for me to better help you
  3. Howie

    Howie Rockstar

    Hmmm.. Ok let me think here..

    I did notice a gurgling sound, but it was weeks before all this went down. Sounded like it was coming from the dashboard. It still makes the noise, but ive just gotten used to it. Usually makes the noise only when the truck is running.

    Coolant is at 60/40 mix as temps below -35'c are normal here.. And it was most definitally coolant. It had that burnt, sweet sugary smell to it.. Blech!

    This truck has the 5.7L Vortec engine. Pics to follow.
  4. oOcornflakeOo

    oOcornflakeOo Rockstar

    is it diesel?
  5. Howie

    Howie Rockstar

    Sorry.. L31, 5.7L Vortec gas engine. Think the last 5.7L diesel was an olds engine wasnt it?

    -35'c out there with the winchill.. So I took as many pics as possible in a short period of time.. if you guys need to see something.. specific, I can get more pics tomorrow.

    Top view of engine:
    Oddly enough everything is bone dry.. Other then the little bit of oil I slopped on the valve cover from the last oil change..

    Laying on belly in snow, Holding camera under truck, pointed at crossmember, towards the front of engine.


    The crossmember is just soaked in this pic, and the steering bar, where you can see a little green drip. Also the wiring harness that runs between the balancer and oil pan is soaked in coolant too.

    Laying on belly camera near the driver's front tire, under the steering box, looking up at power steering pump.


    See some more dibbles of green coolant here, As well as the power steering pump which is just soaked in coolant, as well as more green coolant on just the wire loom of the harness between the balancer and the pan.. which runs from the back of the power steering pump.

    Freezing gonads in the snow, laying in it. Camera in palm of hands pointed straight up at the bottom of the power steering pump.


    From what I can tell by this, the power steering pump is dribbly, and the waterpump looks dry, so I dont think its weeping.

    Any ideas guys?
    Last edited: Jan 2, 2009
  6. oOcornflakeOo

    oOcornflakeOo Rockstar

    It seems as though you still have plenty of coolant still in there but have you ran it today or is all of that dribbly (lol) from a constant leak? cause I really believe from those pics that you have itty bitty little tares in the hose(s).. tomorrow try clearing as much of that dribbly with a rag and check it a couple of hours later to see if its no longer dripping coolant (DO NOT run the engine during those few hours because we're trying to see if the leak is from built up pressure. the absence of pressure hopefully means the absence of coolant) in the mean time, look into pricing for a new thermostat for your truck. shouldn't run you any more than $20-$30.. ttyl
  7. mrfixdit

    mrfixdit Rockstar 100 Posts

    I know you really really don't wanna do an intake gasket but!!!!!! check the torque on the bolts especially the two on the front drivers side I believe they are supposed to be 11ft.lbs. but maybe you should look it up first to be sure I would do it for you but I'm late for work, good luck.
  8. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    If it were me, I'd probably get a cooling system pressure tester (Autozone borrows them out), hook it up, and put a little pressure in the cooling system and see if I could trace the source of the leak that way.
  9. oOcornflakeOo

    oOcornflakeOo Rockstar

    try it m0y way buddy cause I've seem those very same symptoms with my jeep and chevy silverado (1988) once before and it actually looked like to leak was coming from my power steering pump. besides, chances are you wont be able to rent one of those coolant pressure testers out, you'll have to buy one and the one i bought was fairly expensing. I'm not even sure what mrfixdit is referring to or even talking about.. school me if you do..

    the thermostat is the best place to start checking.it is most likely the cause of your over heating if what you're telling me about the top radiator hose collapsing is accurate. if the thermostat is ok, then the next place to check would be the water pump which you would have to first take the belt off and then see if theres any grinding/knocking noise coming from it when you turn its pully by hand.

    other than those two things messing up, there shouldn't be anything else hindering the flow of coolant to that top hose which returns the coolant back into the radiator where the coolant will then cycle again through the radiator, to the bottom radiator hose, out to the block, into the heating coil/element for your a/c's heater located most likely on the passenger side, through some more of the block, through the water pump, around the cylinders and back through the thermostat which stays closed until the block heats up the spring on that thermostat thus opening the thermostat and allowing the flow of the heated coolant up into the top hose. that is the cycle of the radiator.
  10. mrfixdit

    mrfixdit Rockstar 100 Posts

    OK I have more time now maybe I can clarify myself a little better. First you dont have to rent a coolant system pressure tester they loan them free at autozone and advance auto you just have to leave a deposit so they are sure to get it back.Thank MrShorty it was his idea.Second- yes checking the thermostat on second thought changing the thermostat is a must since it has been in storage so long but this is not your sole problem you still have a coolant leak.
    Now if you're like most of us out here then you opened the radiator to check how much antifreeze was left when it got hot thereby releasing the pressure in the system, put the cap back on, let the truck cool down. When things cool they contract, now you have a vacuum in your system, you start the truck the water pump draws, hose collapses. Since you stated the recovery tank was normal and the radiator was 1/4 down I would check the hose to the recovery tank and see if it is gooped up because when it cools and contracts its supposed to draw that coolant from the tank like sucking on a straw.
    From your description and pictures there are two places the coolant can come from. One is the drivers side water pump inlet to the block which would be quite easy to see, Two- the intake gasket at the point just below the corner of the valve cover and they do blow at this point often without spewing into the block. I suggested checking the torque on the mounting bolts to the intake manifold because if one or two are only finger tight or so you know its a problem even if it isn't the leak it soon will be, these bolts tend to loosten on their own if they weren't properly loc-tited and checking the torque on them is very quick and easy ( never loosten only tighten when you check) by the way it is eleven ft. lbs. for the mounting bolts.

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