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Old 02-20-2012, 05:57 PM   #1
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Default Need some advice on cracked heads

Hi all,

I'm a bit lost and need some advice. My car is a 2002 Park Avenue (base NA model) that I inherited from my grandfather. At first I didn't think I wanted to drive it, but it'* a great car. It also has sentimental value.

It now has about 120k miles on it and has had the upper intake fail. I thought I had gotten to it soon enough, but after taking the heads to a local machine shop, there are cracks between the intake and exhaust valves in 3 places.

I'm not sure what to do at this point. I was thinking about buying a crate engine, but sure I can afford it. I'm worried that since the heads got hot enough to crack that there might be other damage to the crank or cam bearings. I do have an engine hoist and can remove and rebuild it and get re-manufactured heads, but by the time I'm done it sounds like it'* close to the price of getting a rebuilt tall block.

Should I be this worried about pulling the block out? Is it worth it to just get a rebuilt? Even if I decide to rebuild it myself, should I have the crank polished, or does that depend on what it looks like? Ohhhh, I'm so confused!

Any advice would be greatly appreciated.

Wayne
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Old 02-20-2012, 06:13 PM   #2
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It is possible the engine had enough coolant in the lower block to stay cool enough, yet the heads being higher having no coolant. IMOanyway.

3800'* are very common in junkyards. Right now I am working on getting my 4th engine(I abuse them)and I spend about $200 per occurance.

If you suspect the crank to be damaged, at least inspect the bearing surfaces and check the clearances.

We have quite a few members here that have experience tearing the engines down and inspecting. Feel free to ask any questions!
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Old 02-20-2012, 06:15 PM   #3
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Holy smokes, cracked heads on a 3.8L? Been working as a tech at a GM dealer for almost 7 years and have never had to dig deeper than lower intake gaskets on a 3.8L. If it were me I'd just pick up a couple used ones at a local scrap yard.
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Old 02-20-2012, 06:32 PM   #4
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And I thought I abused my engines! At this point I really have no reason to believe there is crank surface damage, just a little scared after the head cracks. I don't remember seeing anything milky or foamy in the oil, but haven't drained it yet. It sounds like it'* possible to check the surfaces by just pulling the oil pan and removing a boss or two while the engine is still in the car?

I'd be happy if it just needed the heads replaced. Thanks for the replies!

Wayne
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Old 02-20-2012, 06:38 PM   #5
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I meant to say end cap, not boss......
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Old 02-20-2012, 06:39 PM   #6
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If it happened recently, you may still have time left.
My first coolant issue led me to spun bearing, did a crank swap and bearings. Spun another 3 weeks later.
Last engine I toasted, I punched a rod through the block. Got pictures somewhere around here. These are pretty tough engines.

Check the bottom of your oil cap. That is a good place to see coolant build up.
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Old 02-20-2012, 07:01 PM   #7
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The inside of the cap looks fairly clean to me. I'm going to try to upload a pic...

Wayne
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Old 02-20-2012, 07:09 PM   #8
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Yours is clean, this is what you DON'T want to see....

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Old 02-21-2012, 11:02 AM   #9
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Cracked heads the way you describe is very very very very common on 3800'*. Most never pull the heads and have them magnafluxed to find out. It'* always between the valves. When looking for heads to port, it can be tough to find a set that isn't cracked.

A local was looking for a set of heads. He bought 8 sets before he had two that weren't cracked.

Had you not pulled them, you would have never noticed it in the way the motor ran etc.
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