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Sudden Head Gasket Failure 5.7 TBI?

This is a discussion on Sudden Head Gasket Failure 5.7 TBI? within the Technical / Maintenance forums, part of the General Discussion category; Strange. I bought this truck about 6 weeks ago for $800. The trans was bad, but it came with a ...

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    There is no "t" in Dexron wilbilt's Avatar
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    Sudden Head Gasket Failure 5.7 TBI?


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    Strange.
    I bought this truck about 6 weeks ago for $800. The trans was bad, but it came with a spare. The spare was for a 4WD with the short tailshaft, so I couldn't use it, but was able to borrow the front pump from it to fix the one in the truck.

    I have been driving it every day for 3 weeks, and it has been running fine. Temp when warmed up has never gone over 210, and that was sitting at a light on a warm day.

    I had to go to the store yesterday morning, and noticed a puff of white smoke when I started it up. It's never done that before, but I just thought "valve guides" and went on my way. No more smoke on the trip to town or back.

    Today I was out planning to recharge the AC, and noticed steam coming out the exhaust. I let it run for awhle, but it continued. I shut it off and checked the radiator (full). I ran it with the cap off and it would puke some coolant out every few seconds like a stuck thermostat.

    I pulled the upper hose off the water outlet and was able to open the stat with a long screwdriver, so it wasn't stuck, just maybe non-functioning. No funds for a new stat until payday, so I tweaked it with the screwdriver so that it would stay partially open. I put it back together and the coolant circulates normally.

    It still steams slightly when it builds up pressure, so I guess I'll be doing head gaskets next weekend. I have never seen a head gasket go away without some kind of warning first, like overheating, etc.

    There's no coolant in the oil, which is a good thing. I haven't been into a TBI small block before, anything drastically different than the 60s-70s versions?

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Heywood Jablome Da Tank's Avatar
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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Once you get the tb and intake off, its' the same old song and dance as every other old sbc. Good luck. Shouldn't take you more than a day even if you take your time.
    signature deleted because someone had nothing better to do........

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    There is no "t" in Dexron wilbilt's Avatar
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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Thanks.

    I just didn't want to be trying to pry a head off and then find out they added an extra bolt somewhere...;)

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Steam in the exhaust does not mean there is a blown head gasket. All engine steam under the right atmospheric conditions. Remember, you are drawing moist air into the intake, It's called humidity. Moisture/Condensation can also exist in the crankcase and the fuel tank in small quantities. When the engine warms, this condensation/moisture is vaporized by the engine.

    Check your plugs. Coolant will wash a plug clean.

    Coolant smell in the exhaust (steam)?

    Check all of the indicators before you waste your time tearing your truck apart.
    Last edited by lmadore; 03-27-2006 at 08:24 AM.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    I'm in the same boat. Mine started out minor....white stuff on oil fill cap...than all of a sudden, low coolant, milky oil on dipstick.

    Funny, well not actually...did not overheat either.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Quote Originally Posted by lmadore
    Steam in the exhaust does not mean there is a blown head gasket. All engine steam under the right atmospheric conditions. Remember, you are drawing moist air into the intake, It's called humidity. Moisture/Condensation can also exist in the crankcase and the fuel tank in small quantities. When the engine warms, this condensation/moisture is vaporized by the engine.

    Check your plugs. Coolant will wash a plug clean.

    Coolant smell in the exhaust (steam)?

    Check all of the indicators before you waste your time tearing your truck apart.

    I 2nd that. My 90 steams a good 10 minutes after start up. You could also do a compression and leakdown test. I did that with my 87 after I feared I blew a head gasket. One cylinder measured a little lower than all the others but was still passible. No coolant in the oil. I drove it another 6 months before that cylinder gasket gave out and it started smoking from leaking.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    I initially thought it was due to cool temps and condensation, as we have had a LOT of rain lately.

    It definitely smelled like coolant, though.

    I drove it to work today and have been driving between sites, no steam or unusual smells. Of course, with the t-stat tweaked open, it isn't even warming up to temperature. It's only getting to about 120 degrees.

    I will pull the plugs when I get a chance. I get paid once a month, so there's no chance of buying any parts until Friday (pay day). I am also thinking it could be a leak from the intake manifold water passage into an intake port.

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    There is no "t" in Dexron wilbilt's Avatar
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    Re: Sudden Head Gasket Failure 5.7 TBI?

    So here's an update...

    I drove it all last week to work and everywhere else, about 250 miles. No hint of steam from the exhaust, no lost coolant. Of course, the t-stat was tweaked open, so it never really warmed up, either.

    Yesterday, i got a new stat and put it in. I filled it up and started it, and within two minutes it was blowing steam out the pipe. I let it run for awhile to completely warm up, and there was no change.

    I'm going to buy a gasket set and tear into it today. I need to take my daughter up to meet the bus for a school trip in a few minutes (3:30 AM to meet the bus...WTF) and sure miss the old Chief Auto Parts open-24-hours store.

    I haven't had this truck very long as wasn't planning to get this intimate with it yet, but it decided it wanted to f*** me.

    I should set up my webcam out there so you can all watch me cuss and throw stuff...

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    are you absolutely sure its a headgasket? are you losing coolant, did you do a leakdown test? i really wouldnt jump into that kind of job with out knowing first. but thats just me.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    I don't have the capability to do a leakdown test.

    I pulled the plugs this morning, #6 and #8 were wet. Not *really* wet, but sticky and sweet-smelling.

    I would rather it not be a head gasket, but would prefer that to a cracked head or block. I tore it down, in between hailstorms, and it was apparent there was some leakage in those two cylinders.

    Interesting that in the Fel-Pro gasket package was a paper showing the differences between "heavy-pattern" heads and "light pattern" heads. It went on to explain that the light heads have an ongoing problem with blown gaskets, due to very little "meat" between the combustion chamber and the lower water passage.

    Sure enough, my heads are the light castings, and the margin between the chamber and the coolant on #6 and #8 is *very* small. There is evidence of some erosion on the head, so I am considering this a temporary repair.

    Hopefully, I can drive it till it drops (supposedly about 50K on this engine) and then replace it with a reman or crate motor.

    I got the heads and manifold back on today, and should finish it tomorrow.

    I'm getting slow in my old age. 20 years ago, this job would have taken half a day. Of course, I wasn't working outside during thunderstorms then, either...

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Good luck, I just got done with mine today...well, sorta. I stated it up and it run perfect. Still minor things to tweek on.


    $109 for the gasket sets and $84 for the resurface on both heads. Whew....pain in the ass.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Good stuff. You're making better progress than I. I just took one look at my Suburban today and said I'd wait until tomorrow to finish the head gasket job on it.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Quote Originally Posted by JKB315
    Good stuff. You're making better progress than I. I just took one look at my Suburban today and said I'd wait until tomorrow to finish the head gasket job on it.
    I really didn't want to tear into it yesterday, but I need it for work tomorrow.

    Like the saying goes, "in between a rock and a hard place".

    I hope it runs when I get done with it.

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Final update (hopefully) on this project.

    I braved the freaking rain again this morning and finished up installing the exhaust manifolds, TBI, etc. The head gasket set didn't include exhaust donuts, so my wife picked them up for me yesterday when she was in town. I know it lists two different sizes, so I sent one of the old ones with her to show them.

    They sold her the wrong ones, and I am seriously beginning to think that a double-digit IQ is a requirement to work at a parts store. But that's another rant.

    I finished putting it together with the old donuts (which leak badly), filled it with coolant, and fired it up. It started right up, but had a distinct miss. I'm sure I got some coolant where it shouldn't have been while pulling it all apart, so I wasn't too concerned. I kept busy topping the radiator as it warmed up and watched for coolant and fuel leaks.

    Eventually it smoothed out, warmed up and opened the thermostat. Good flow, so I waited out the last few air bubbles and closed the cap. I let it run for about 20 minutes while watching the pipe. No steam, which is a good thing. I set the timing and headed for the parts store to exchange the incorrect donuts.

    I immediately noticed that it was running better than previously, and aside from sounding like sh*t due to the exhaust leaks, ran perfectly and at temperature the entire trip. Previousy, I had noticed an intermittent miss at highway speeds. It was probably when one of the cylinders got a good shot of coolant.

    I got home and changed the donuts. I still have leaks because one stud on each side unscrewed from the manifold, and I can't get enough pressure against the springs to screw them back in. It will have to wait for another day, as I'm tired of lying under the truck in a mud puddle.

    I'm dirty, wet, and scarred enough for one weekend, but I feel much better...;)

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Is steam a common head gasket failure sign? What are typical or definate signs of a head gasket failure?
    2008 Chevrolet ECSB - 5.3 1/2 Ton 4.10 Gears 4x4 - GM Performance Parts Air Intake - Flowmaster Exhaust - Edge Tuner - 2/3.25 Drop - Debadged

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Steam that smells like coolant is a good indicator of a blown head gasket. In this case it was relatively minor seepage.

    In more severe instances, it would be accompanied by rapid loss of coolant and overheating.

    Other ways to test would be checking the compression in the cylinders or performing a leakdown test and comparing the compression and leakdown rates among all the cylinders. These methods can also indicate other problems ( rings, valves, etc).

    There is a chemical test kit that checks for the presence of exhaust gases in the coolant. Sometimes you can see continuous bubbling in the radiator that smells like hydrocarbons/exhaust.

    This time it was a minor leak, only occuring when the coolant temperature and pressure were up.

    Of course, any of the symptoms could also indicate a cracked head or block.

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    I have an 89 with a 350, I had white smoke from my exhaust and my oil was like chocolate milk with lots of cream. I had my heads redone and replaced water pump, thermostat, new Edelbrock Performer Manifold for TBI and all gaskets Fel-Pro. I am not sure if I should just drop my pan and replace the oil pump also because of contaminated oil, what do yall think?

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    Re: Sudden Head Gasket Failure 5.7 TBI?

    Quote Originally Posted by GrownUpChevy
    I have an 89 with a 350, I had white smoke from my exhaust and my oil was like chocolate milk with lots of cream. I had my heads redone and replaced water pump, thermostat, new Edelbrock Performer Manifold for TBI and all gaskets Fel-Pro. I am not sure if I should just drop my pan and replace the oil pump also because of contaminated oil, what do yall think?
    What I would do is fill the engine with some cheap thin (5w-30)oil, replace the filter, pull the valve covers then turn the oil pump with a drill to cycle the oil thru the engine. Once I felt comfortable that the oil went thru the engine I would start it up and watch the oil pressure gauge. 30 seconds after the the gauge goes to normal pressure, turn it off and replace the oil and filter with the good stuff.
    1991 C1500 Ext. Scrapped. I still have the engine, tranny and Detroit tru-trac.
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    Re: Sudden Head Gasket Failure 5.7 TBI?

    head gaskets usually breakdown over time if you dont flush your cooling system atleast once a year or add somthing to help the eletrolyte process in the coolant. i flush my radiator and motor atleast once a year and ive been on the same set of head gaskets in my mud truck for atleast 150-200k miles

 

 

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