Cracked Head

[MinorityWRX]

I had my block replaced due to a thrown rod, by SUBARU. 8,000 miles later I now have a cracked head. Subaru scanned my car and revealed that I had a PO171 code, Exhaust running lean, and a PO546 code, Exhaust temperature sensor. I have a cat before the sensor. My question is, can either of these codes lead to a cracked head in any way? My theory is that the exhaust running lean code is because the engine is lean causing extreme temperatures in my engine which explains the exhaust temp code. Extreme temperatures cause cracked head?

[MilesFox]

your mechanic is smoking crack if he didny use a compression gauge or check the coolant, oil.

you have engine codes pobably beause you have a lean condition caused by a bad o2 or an exhaust leak. engine codes dont tell you if hte heads are cracked. cracks in the exhaust ports will tell you that.

a cracked head you would have poor compression, water in the oil, vice versa, steam out the tailpipe, bubbles in the radiator

[b7g]

Originally Posted by MinorityWRX

I had my block replaced due to a thrown rod, by SUBARU. 8,000 miles later I now have a cracked head. Subaru scanned my car and revealed that I had a PO171 code, Exhaust running lean, and a PO546 code, Exhaust temperature sensor. I have a cat before the sensor. My question is, can either of these codes lead to a cracked head in any way? My theory is that the exhaust running lean code is because the engine is lean causing extreme temperatures in my engine which explains the exhaust temp code. Extreme temperatures cause cracked head?

sounds like something your dealer should have checked for (hairline cracks, some measurements out of spec) when they replaced your short block. It very likely was a preexisting condition that caused this to happen.