3800 Blown Head Gasket or Cracked Block???

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sr71_rgl

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  • #1
    This is definitely not one of the more enjoyable posts I've had to make but during tonight's "test the new plugs" highspeed run my car just quit on me. I was breaking through the 100mph mark when all of a sudden nothing....no noise, no smoke and no power. The gas pedal did not command more fuel and I was rapidly slowing down so I just turned the car off and coasted to the side of I88 going west just before Eola. Lucky for me Hale lives nearby and was willing to bail me out (thx bigtime steve). My car did not set one single code and there were none in memory when I tried to retrieve them. Plugs were pulled and were soaked in fuel so those were replaced (all were totally soaked with gas yet #4 smelled more like coolant). The fuel pump fuse was bypassed yet we still couldn't get it started. The car would crank fine but just wouldn't catch even after we confirmed we were getting spark to cylinder 5. My battery must have gotten worn from all the cranking cuz it was only pulling 11v idling and around 9v when cranking so we let it charge a little longer and cranked it up several more times. It seemed like it wanted to start but just couldn't. It caught and ran twice for maybe 10 secs before dying...almost sounded like a pffft pffft noise like it was losing compression but it's hard to tell. That's when steve noticed the puddle of coolant near the front right tire. I tried starting it when the flatbed got it back home and the tach spun all the way full travel and then fell back to 0...so it seems the CPS is still functional. I've taken my car up much faster than what I did tonight in the past with no problems at all. I was only seeing 10.5 psi max boost before it died. I'm hoping it's just a head gasket but what's the chance that I cracked my 71k mile block? I'm leaning towards head gasket because my #4 cylinder has hosed 2 plugs in the last month and this one smelled more like coolant than the others did. Is it possible the 2 bad plugs in slot #4 were a warning the head gasket was leaking?
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    GTPictor

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    Nov 16, 2008
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    McHenry
  • #2
    Id say head gasket. Unfortunatly thats what made my car go boom. 135+ run with cracked gasket let all the coolant into my oil gally and roasted my bearing cleaned the top half up and rinsed all the crap out the bottom and seh ran fine till 6 hrs later where she spun a bearing at the track and blew cylinder 2 through the block. I wish you luck but be carefull.
     
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    sr71_rgl

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  • #4
    Originally posted by ThaLord@Dec 30 2003, 09:45 AM
    damn... sorry to hear that... I would also say head gasket... seems like steve is always there when you need him.. doesn't it?

    Long Live Hale!
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    Hale is the man...if he ran for president he'd have my vote :p


    Adam...I hope you're right about it just being a gasket, but wouldn't my car still run even with a bad gasket? Mine cranks and cranks but just won't catch....I guess my battery is still shot. I'm gonna get a charger.
     
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    sr71_rgl

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  • #8
    Originally posted by CoolGTX@Jan 2 2004, 07:41 PM
    verdict?
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    Looks like a defective TB gasket is the culprit. It was failed on my last romp to 100mph and started pumping coolant into the motor pretty much like Adam said. The rear head didn't show any stress but the gasket was soaked w/coolant and stripped to the metal around the 6 piston. I'm going to attempt the front head myself and see if its any good which it prolly is but should be replaced regardless. BTW...does anyone know what the correct compession value a functional piston has? My rear bank was didn't havea reading over 70psi for any pistons.
     
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    imported_Ron Vogel

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  • #10
    The TB gaskets are notorious for leaking, but I'm pretty surprised to hear it failed like that. The first time I pulled off my TB, the gasket was soaked. I picked up a new gasket, and covered it with chapstik to seal it, and make it reuseable. I had to do some work on it a couple of months down the road, and it was wet again when I took it off. Since then I put a light coat of blue rtv on the gaskets to waterproof them and all's been well. I'm not saying the TB gasket couldn't cause this, but testing out some spacer designs I was working on; one of them leaked real bad, and I drove the car home about 5 miles barely running sucking in coolant. I cleaned it up, changed the plugs and the oil and it was fine. At the time all my plugs were soaked in coolant. What I'm wondering is if there was an even distrobution of the coolant, or if it is concentrated in one or two cylinders? '97's & '98 heads are prone to crack in-between the valves, and this should definately be checked, although head failure usually happens slower, and not so sudden. Let me know if there is anything I can do to help. I don't have internet at home, because I won't have a phone until the 15th, and I'll be off of work until the 12th, so call my cell.
     
    gtphale

    gtphale

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    Nov 9, 2008
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  • #11
    Yea all the cylinders were soaked. The gasket between the air intake and the coolant passages was shriveld up with some gasket gunk. I'm thinking that this gasket gunk isn't compatible with Dexcool???? Not sure I use a read rtv sealant on my ls1 with no problem. When we drained the oil we got well over a gallon of oil and coolant from the pan. So there was plenty in there.
     
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    sr71_rgl

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  • #12
    Originally posted by Ron Vogel@Jan 5 2004, 08:29 PM
    What I'm wondering is if there was an even distrobution of the coolant, or if it is concentrated in one or two cylinders? '97's & '98 heads are prone to crack in-between the valves, and this should definately be checked, although head failure usually happens slower, and not so sudden.
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    The back bank of pistons were definitly low on compression (~ 30-50psi). We inspected the head gasket and there was a fairly large portion of paper missing between piston 4 and 6 (lowest compression of the 3). I'm not sure if this was caused by all the coolant the TB was letting in or not, but the heads have no cracks that could be seen with the naked eye. Hale and I are going to be reassembling everything sometime this weekend (unless I can get the parts sooner) and you're more than welcome to come by and check out the gaskets from the TB and the heads. I think once you see that TB gasket it'll be more obvious to you as to why it failed.
     
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    Royalgtp

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    Dec 24, 2008
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  • #13
    If you do a compression test and all cylinders are fine, except for two cylinders next to each other, youve probley blown the head gasket in between the two pistons.

    BTW, my TB gasket was leaking coolant for a little bit to. Some of that crap was in my SC intake port, and most likely my engine....anyway, i did a oil change and plug change and couldnt detect anything :) :unsure:

    ANyway, i could see how it could ruin your engine 1,2,3. Is it safe to block the TB passage, or, only in the summer??
     
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    imported_Ron Vogel

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  • #14
    Oood thing they have internet in the delivery room!! Anyway, onr thing to remember is that there is not much sealing area on this particular tb. Nick wanted the outlt opened up to match the ported inlet of the sc. Most probably this is why the gasket failed. Since there wasn't enough material to open it up to 75mm and still have it seal, the edge was rounded off a litle insted of opening it up all the way, so as to leave some sealing area.
     
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    sr71_rgl

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  • #16
    Originally posted by CoolGTX@Jan 6 2004, 05:49 PM
    while you have the intake manifold off, tap and plug those water jackets for the T/B....... ;) mine is finally blocked with the I/C..... :ph34r:

    might as well tap and plug the EGR, while your at it.
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    Good suggestion JO...I'll have the time to do it while my new p&p heads show up ; )
     
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    sr71_rgl

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  • #18
    Originally posted by Ron Vogel@Jan 6 2004, 02:52 PM
    Nick wanted the outlt opened up to match the ported inlet of the sc. Most probably this is why the gasket failed. Since there wasn't enough material to open it up to 75mm and still have it seal, the edge was rounded off a litle insted of opening it up all the way, so as to leave some sealing area.
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    I"m not sure that opening the TB up to fit my SC (75mm) was the cause of this failure. The glue the factory puts on the stock gasket to make the seal was still there fully intact, on the existing material that was left over after the gasket was trimmed to fit the new opening. What looks like happened was whatever the extra mystery adhesive was stopped the factory glue from making its bond w/the TB. This area became weak and started allowing coolant through. I noticed in a previous post you mentioned you used blue RTV....I don't recall seeing anything blue on the TB...just a shiny almost lacquer type coating evenly spread over the gasket. Did you use any of this stuff on the other TBs you did?
     
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    imported_Ron Vogel

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  • #21
    I started with the Chap stick, but it didn't prevent the leaks from the water jacket completely in the long term. I switched over to blue rtv because it had better sealing proporties and it's sensor safe. It's primarily used for valve covers and water pumps, but not for carbs since it's not to good with gasoline. The advantage to it is it's elasticity and fast curing time. After curing, it's pretty much a rubberized silicone gasket. There aren't any warnings about Dexcool, the only warnings are for chlorine rich solvents. Here's the link to the TDS for it:
    http://www.permatex.com/MSDS_data/tds_files/80022.pdf
     
    gtphale

    gtphale

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    Nov 9, 2008
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  • #22
    do you have some at home still? With some dex cool? put on some paper or something and put dex cool on it after it dries. See what it looks like not sure if it would only happen long term or not. Just want to make sure that if your still using that its compatible with dex cool. I would think it would be but never know. Something you might want to look into.
     
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    imported_Ron Vogel

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  • #24
    Yeah, but the red stuff is the high temp stuff and sets up a lot harder. I've used it on exhaust flanges and headers for years. It takes more than twice the time to cure than the blue, and is more messy to work with. I'm still unpacking the garage stuff, but I'm sure there's some there somwhere. The only problem with soaking it is that it's not really a good test. I'd need to simulate temperature changes and pressure, plus how long should I test for?
     
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