EJ251 Head gaskets rebuild failure

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Hi everyone.

Recently I was doing a full engine rebuild for my 2002 Outback 2.5. I am a complete novice in engine rebuilds and this was my first engine.
I was advised that I should use aftermarket MLS head gaskets and so I ordered the kit and installed it. I reused my head bolts.
Both my heads were machined by the machine shop, and the valves were reseated. The short block was also professionally rebuilt.
I put everything together and followed the factory manual, but on the first start, the engine ejected all oil through the right head gasket :(
Back to square one...

I just want to ask experienced builders, do you torque down MLS head gaskets differently? And should I upgrade or just use OEM ones?
I know I should've done more research, but I guess you live and you learn from your own mistakes.
I also noticed that one of the bolts was acting strangely - I couldn't hand-tighten it. Maybe my old bolts were stretched.
 
You need a service manual and find out why that one bolt "acted strange".
New head bolts are a better idea.
Check all the threads for damage on the block and there is a pattern to head bolt torque.
OEM gaskets are the best. Measuring head and deck for flatness is a priority.
And the model is?
 

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  • 2002 Outback.png
    2002 Outback.png
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I have a similar manual. I followed the same process, but I think it's for OEM head gaskets, not for the MLS ones.

Extracted from the manual:
Tighten cylinder head bolts.
(1) Apply a coat of engine oil to washers andbolt threads.
(2) Tighten all bolts to 29 N·m (3.0 kgf-m, 22ft-lb) in alphabetical sequence.Then tighten all bolts to 69 N·m (7.0 kgf-m, 51ft-lb) in alphabetical sequence.
(3) Back off all bolts by 180° first; back them offby 180° again.
(4) Tighten bolts (a) and (b) to 34 N·m (3.5kgf-m, 25 ft-lb).
(5) Tighten bolts (c), (d), (e) and (f) to 15 N·m(1.5 kgf-m, 11 ft-lb).
(6) Tighten all bolts by 80 to 90° in alphabetical
 
Head gaskets can not be reused
"MLS head gaskets" search offers .....

If unsure, contact MLS for their instructions.
New water pump, coolant and timing belt kit correct?
Valve adjustments?
 

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  • Head bolts and torque.pdf
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Last edited:
Yes, I installed everything new, I only resued the oil pump. Thank you for the link, I used different head gaskets, but I will check out Fel-pro
 

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