Cylinder heads: Cleanup, Rebuilld, or Replace?

Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's, Olds 98 91-96, Buick Lesabres and Park Avenue 91-96. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.
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gk35
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Year and Trim: 1994 Bonneville SE

Cylinder heads: Cleanup, Rebuilld, or Replace?

Post by gk35 »

1994 Bonneville, 3800.

Severe overheating issues. After replacing radiator,thermostat, UIM and LIM gaskets with no help in overheating, decided to pull the head cylinders to check gaskets. Lo and behold, 90% of the water ports in the head gaskets were completely clogged.

So now I'm wondering if I should give the cylinder heads a good scrubbing and pop them back on, or have the cylinder heads rebuilt (i.e. valve job- something I don't want to do myself), or simply purchase rebuilt heads for around $250 each.

She's got 200K miles on her. And I plan on using her as my DD for at least another 50K miles. Any recommendations?
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MattStrike
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Re: Cylinder heads: Cleanup, Rebuilld, or Replace?

Post by MattStrike »

Overheating an engine can lead to cracked heads. The point where they tend to crack is the narrow spot between the valves. Use a fine wire wheel to clean the metal there until it's shiney and you can see if they are cracked. Might need a magnifying glass and flashlight to see any cracks.

If they are not cracked, you should be OK with a good cleaning and reinstall.
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95naSTA
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Re: Cylinder heads: Cleanup, Rebuilld, or Replace?

Post by 95naSTA »

You can heat any suspect areas with a torch to see if oil bubbles out of the potential crack.
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