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head gasket leak


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#1 knifer94

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Posted 27 February 2012 - 08:17 PM

well another question from the new guy. the 98 z71 i just bought is leaking antifreeze from what looks to be the heads(both heads between head and block) on the 5.0 engine. a ford lover of mine said this is a commond problm on these. said it had to do with the gm coolant. the truck has 69,000 miles on it. any comment is welcom. thanks, david

#2 txab

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Posted 28 February 2012 - 12:17 AM

I'd check intake gaskets first. More common than head gaskets

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#3 K5MudDog

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Posted 28 February 2012 - 04:22 AM

I'd check intake gaskets first. More common than head gaskets




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#4 knifer94

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Posted 28 February 2012 - 08:37 PM

the leak seams to be on the lower side of the heads, not the upper side where the intake is. no one heard of the head gasket failure theory.

#5 txab

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Posted 28 February 2012 - 09:59 PM

I've heard of it. I just know intake manifold gasket failures are common on wet intakes. Clean everything up. Add dye to the coolant, then find your leak

Edited by txab, 28 February 2012 - 09:59 PM.

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#6 govener71

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Posted 28 February 2012 - 10:11 PM

You could also clean things up and get a pressure tester from pretty much any autostore. Pump up the pressure to opperating pressure without running it and see where it is possibly leaking from. If nothing else you may need to replace heads depending on how much the truck it worth to you. When my truck did it there was kind of two options. Fix the heads with remans for $2400 at a shop, you could also do it your self and same some coin. You would also be able to run the motor until the coolant runis the rear main seal or other parts that coolant will cause wear in and just replace the motor when it goes.

My truck had 187,000 miles on it when i had new heads put on. If I had to do it again, I would do the same thing. A shop is expensive but much faster than do it my self. To boost my ego I could do it, but I need to go to work and dont have the tools that others do to do it correctly and efficently.
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#7 Ape0r

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Posted 29 February 2012 - 12:33 AM

You could also clean things up and get a pressure tester from pretty much any autostore. Pump up the pressure to opperating pressure without running it and see where it is possibly leaking from. If nothing else you may need to replace heads depending on how much the truck it worth to you. When my truck did it there was kind of two options. Fix the heads with remans for $2400 at a shop, you could also do it your self and same some coin. You would also be able to run the motor until the coolant runis the rear main seal or other parts that coolant will cause wear in and just replace the motor when it goes.

My truck had 187,000 miles on it when i had new heads put on. If I had to do it again, I would do the same thing. A shop is expensive but much faster than do it my self. To boost my ego I could do it, but I need to go to work and dont have the tools that others do to do it correctly and efficently.


Swapped heads out on my '04 w/ 149k two weeks ago due to coolant loss into oil. Fairly certain one of them was cracked, based on finding sludge under only one valve cover and not in the motor itself. Head gasket looked fine. Did not have castech heads.

Worked 8:30am-7pm with two buddies, got the new heads on, rocker arms in, and exhaust back on. Put it the rest of the way back together (intake, generator bracket, etc) the next day in about four hours. Cost was $675 all in (tools, gaskets, heads, fluids, etc) using reman heads I picked up on ebay from someone who bought them for a built motor and then decided to go bigger for $160 shipped. New heads would have cost another $700-$800.

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Speaking to the OP, I would use dye and a pressure tester before jumping to any conclusions about head gaskets. It seems improbable that a head gasket would fail from the coolant passages out, they usually "blow out" from the cylinders. Make sure before you tear into your motor, it is a BIG job.

Edited by Ape0r, 29 February 2012 - 12:33 AM.

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#8 Gurrzt

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Posted 29 February 2012 - 08:33 AM

When engine is cold, take off the radiator cap and start the vehicle, when the thermostat opens, if you see "bubbles" coming up to the top, you have a head gasket problem.

#9 txab

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Posted 29 February 2012 - 08:48 AM

You can also use a special test strip that checks for combustion gasses in the coolant. Available at most auto part stores

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#10 knifer94

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Posted 29 February 2012 - 08:15 PM

all that is fine but what i wanted to know is if chev had a known problm of head gaskets blowing. there is no water in the oil and no air bubbles in the radiator. i plan on checking everything out before i do anything. i have the tools and the know how to do it. put them on my 95 s10 4.3 last year. thanks, david

#11 TahoeMike

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Posted 01 March 2012 - 08:23 AM

all that is fine but what i wanted to know is if chev had a known problm of head gaskets blowing. there is no water in the oil and no air bubbles in the radiator. i plan on checking everything out before i do anything. i have the tools and the know how to do it. put them on my 95 s10 4.3 last year. thanks, david

To answer this question, it is no. Although it can and does happen, the most common issue with these engines was bad intake gaskets, as mentioned above. That's where I'd start because intake gaskets are a bit easier than head gaskets.
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#12 knifer94

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Posted 01 March 2012 - 09:11 PM

intakes are a lot easier that for sure. if i can quit making knives long enough next week i'll see where the leak is. thanks for all the help and i'll post the results. david




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