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Almost positive it's a HEAD GASKET issue- ***** UPDATED *****

Discussion in 'The Garage' started by Can Can, Mar 18, 2004.

  1. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Almost positive it\'s a HEAD GASKET issue- ***** UPDATED *****

    *******SEE THE BOTTOM FOR AN UPDATE******


    I've been having some coolant system issues and I thought I had everything figures out until tonight........ /forums/images/graemlins/angryfire.gif

    I checked the rad before I left tonight. It was down about 2 cups, so I topped it up to the neck. I drove about 65 miles and when I got to my destination I popped the hood and the top rad hose felt like it was gonna explode, although it wasn't very hot. The truck ran a TEENY bit warmer than normal on the trip there.

    Before I left to come home, I checked the rad hose again. It felt like whatever pressure had built up in it had disappeared. The overflow was at a normal level and the rad was still basically full to the top.

    On the return trip, the truck yet again ran a little hotter than normal(maybe 5-10 degrees). When I got home, the top rad hose was again VERY hard. This time the overflow tank looked like it had filled up with the 2 cups of coolant I had earlier put into it. I loosened the rad cap about a 1/16 of a turn and LOADS of air came bubbling out(it took about 5 minutes to stop burping). After all the pressure had relieved I popped the rad cap and it looked low by about 2 cups or so(just like it was before I left my place tonight).

    So here are my 3 questions:

    1. I guess it's safe to assume that air is getting into the cooling system either through the head gasket or a crack in the head. Which one would it be? My performance has stayed the same all throughout this ordeal, and I'm not blowing any white smoke.

    2. If the system is getting filled with air, I can see why it's getting overpressured. But why is it not burping the air out by itself as it builds up to unnaceptable levels? Is my rad cap too strong?

    3. Is there a chance that I'm simply just trying to overfill the rad? It seems that every time I top it up the same amount ends up in the overflow. Of course, this doesn't explain the pressure buildup and the burping, does it?

    Please help me before I have a heart attack worrying about this friggin' issue........ /forums/images/graemlins/1zhelp.gif
     
  2. Triaged

    Triaged 1/2 ton status

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Water expands when it gets hot. When you drive the truck the pressure will build up (why the upper hose was firm). When it gets over the pressure that your rad. cap it (about 12-15psi) some of the fluid will go into the overflow. When it cools down it will just suck it back in (as long as you didn't open the cap when it was hot). Opening the cap when it is hot will cause the coolant to boil and steam out if the truck is running a bit warm. Bottom line: don't open the rad cap till the truck is cool, and I don't think your problem is a head gasket.

    If you want to check for a head gasket pull all the plugs and hook up a air fitting to each cylinder (at TDC of compression stroke). Open up the rad cap, remove the air cleaner, and pull off the oil fill cap. You should hear a bit of air comming out of the oil fill cap and none out the carb or rad. Do this for each cylinder.
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    The upper hose becoming hard is normal after it is at operating temperature. The pressure is what makes it hard and when the engine cools it should be much softer. I would bet that maybe you should replace your radiator cap though. It doesn't sound like you have any kind of problem going on. As the temperatures outside start getting hotter then usually your truck will start to run a little warmer as well. /forums/images/graemlins/thumb.gif
     
  4. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Thanks for the info, brothers. I kind of suspected that there may be a problem with my rad cap because the sucker is REALLY hard to spin off even when the engine is cold.

    I'll try replacing the cap and see what happens. I do know that it has't been replaced in about 6 years.

    And if my head gasket WAS indeed shot, what should be happening? Both you guys seem pretty sure that the gasket is not the issue, so I'm curious why you don't think it's involved?
     
  5. big pappa b

    big pappa b 3/4 ton status

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    If it was head gasket there is a good chance you would have antifreeze in the oil or vise versa
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Almost always when you blow a head gasket you will have white smoke coming out the exhaust pipe and usually have water mixing with the oil. Sometimes you can have a blown head gasket without those symptoms but with others instead such as hyrdo carbons in the cooling system. With the engine running and the radiator cap off do you see bubbles in the radiator? If you do then you may have a blown head gasket otherwise I would say you are ok and changing the cap is a good idea.
     
  7. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Well if it's got exhaust blowing into the coolant then you can pick up a kit that will detect the exhaust. NAPA sells them.

    GM trucks are not know for blowing head gaskets. They are more know for cracking heads in on of the valve chambers in the head. I would top it off and just keep an eye on the resevior for a couple weeks.

    Also a spark plug in a cylinder that has coolant entering it is often clenaer then the rest.
     
  8. jimmyjack

    jimmyjack 1/2 ton status

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Take it to a radiator shop or any garage and have them pressurize the radiator tank. You'll know of a problem prety quickly. Also, the vented caps (with the red lever on top)don't work on the overflow systems.
     
  9. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    BTW guys, this is on my 83 6.2 diesel.

    I noticed a small amount of bubbles at the surface of the coolant while the truck was warming up this morning. How much bubbling is normal? I'd imagine that having some air bubbles in the system is normal due to the water pump turning? /forums/images/graemlins/dunno.gif

    What are the symptoms of a cracked head? I thought a cracked head would cause you to lose coolant. As far as I can tell, my coolant isn't dropping significantly. /forums/images/graemlins/1zhelp.gif
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    [ QUOTE ]
    How much bubbling is normal? I'd imagine that having some air bubbles in the system is normal due to the water pump turning?

    [/ QUOTE ]

    Bubbling is not normal, the turning of the water pump with the thermostat open will just make the coolant 'run' but there shouldn't be any bubbling.

    Head cracks are pretty common in 6.2's from what I understand, and head gasket failures are also common enough. I'd have the coolant system checked for exhaust gases...

    Rene
     
  11. Blue85

    Blue85 Troll Premium Member

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    [ QUOTE ]
    GM trucks are not know for blowing head gaskets.


    [/ QUOTE ]

    Except for the diesels is what I thought and then I read that he has a 6.2, which I always suspect for cracked/warped heads and blown head gaskets.
     
  12. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    Well, that kinda tells me something's wrong. I just don't get it though. I have no white smoke, no overheating and no coolant loss.......

    I guess I'll pick up a pack of those coolant test strips. Are there specific test strips for diesel engines?
     
  13. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Re: Almost positive it\'s a HEAD GASKET issue- PLEASE READ

    ********** UPDATE ********

    Well, I just got back from the shop. There is NO sign of exhaust fumes in my coolant!!!!!

    My mechanic figures that the bubbles I'm seeing is actually foam caused by the stop leak I put in the rad about a month ago. I'm gonna drive the truck for a little while and see how things go.

    I also replaced the rad cap and that seems to have eliminated my overpressure problems. Funny how the little things can bite you in the butt, eh?

    Thanks for all the help, brothers!!! /forums/images/graemlins/waytogo.gif
     

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