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How bad is it? Tiny cracks on top of engine case.


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05 Subaru Outback, 234k miles. Pulled the engine to redo someone's head gaskets. Got everything cleaned up and discovered tiny cracks on the surface of the engine case. I'm used to the old 1.8L EA82 engines. Is this common? They weren't leaking anything and not really in structural spots. Are these possibly from the casting process? 

The real question is do I just reassemble and hope for the best or look for a replacement engine? My thoughts are to just put in the new head gaskets and send it. Previous owner had just done the water pump and timing belt. He didn't want to bother with leaking head gaskets again. 

Upon disassembly I discovered that the last person to do head gaskets didn't torque it properly. There was one bolt that was no longer torqued. Heads check out for flatness within specs. 

 

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Aluminum or aluminium is cast using sand/glue casts. Due to the rapid change of temperatures there minor cracks at the liquid aluminum and sand interface. Once the sand or mold is stripped away you see these little burs. Some brands polish them away, others leave them. You can see on machined parts (32222 written photo) there are no cracks in the aluminum where the top is machined off. There are also other marks on the engine that shows how often the master cast is used, usually a grid with dots. Manufacturers have learned how many times a master can used. Also during the master sand mold pressing step some sand from the previous mold preparation can stick onto the master, this leaving some 'extra' sand for the next mold. All these steps result in these small cosmetic lines.  If you are willing to spend loads of time you can remove them.

(see: https://www.youtube.com/watch?v=hJkwUVSpNPw)

 

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Thanks all! Upon further inspection,  prior to your comments, I realized that these look like cracks but most are actually raised lines. Which verifies with what you've said. Great news! New head bolts and gaskets and we're back on the road. 

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Ok well, now the bad news. I received the head gasket set and started reassembly. The lower right bolt that was loose when I disassembled won't get to 51 ft lbs. It's got to be stripped in the block. Is there a decent fix? Helicoil possibly? The TimeSert kit is costly...

Or, I'll have to bite the bullet and get another engine. For reference, the car has 234k miles. Even worth it??

 

Thoughts? 

Thanks all! 

Edited by Dbeluscak
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