2008 Camry 2.4L engine. No history of running hot. Plastic top cracked on radiator. No red lights, No codes but obviously overheated. Engine runs but water bubbles robustly in radiator. Steam coming out of tailpipe. Pulled head. No obvious cause of overheat detected. Can see damage on head gasket between cylinders 2 & 3. Haven't looked into water pump yet but that's next. Plan to replace thermostat.
1) What are the typical causes of this type of problem?
2) What are the block warpage tolerances? According to one video block warpage tolerance is 0.20 mm ( 0.008 inches) yet another video gave 0.003" tolerance. Neither cited an official source for their information.
3) What are the head warpage tolerances?

 

Cyl head: Face side 0.0020 in., intake manifold side 0.0031 in., exhaust manifold side 0.0031 in.

Block: 0.0020 in.

When you removed the head did any of the bolts seem loose? If so check the block threads.

Check for cracks. Possible to have a crack leading to coolant leaking into a spark plug hole.

 

Thanks for the dope. Interestingly enought, one of the exhaust side head bolts adjacent to the leak point was not as tight as the others. All of the head bolts came out with a heavy coat of oil on them and I haven't cleaned them up yet. Besides seeing aluminum on the bolt threads, what other signs should I look for regarding the block threads?

 

As I was ruminating on this and Joey P's reply I made the connection that the head bolt was loose right where the head gasket failed. It was the center exhaust side head bolt and the gasket failure was between the #2 & #3 cylinders. When I pulled the head there was a milky substance on top of the head gasket in that area that was maybe an inch long right between the cylinders. When I wiped the head gasket the black coating was gone from that area on both faces of the head gasket. This may be the first smoking gun I've found that explains what happened. If the bolt loosened during service it could allow leakage. The question is, do the head bolt threads in the block fail during normal service?

 

This model engine had issues with some threaded holes in the block failing. It started sometime around 2002 but not sure when Toyota finally fixed the issue.

Research 2AZFE head bolt thread failure. See link below.

https://www.camryforums.com/how-tos/...-thread-396958

 

Maybe I won't need to do that. Keeping fingers crossed. Just sat head back on block (no hd gasket) and finger tightened head bolts. Came upstairs to get torque spec. I figure that if the bolts will torque to spec the threads must be ok. If the threads are compromised perhaps retorqing will cause them to go ahead and fail. If no failures, then I will assume all is well with threads.

Just came back up. Placed head on block and fully torqued all ten bolts without issue. I believe the block is OK. The head shows 0.007" out of flat lengthwise and 0.005" from front to back. I'll have to get the firedeck cut. Made arrangements for that this afternoon and may be able to get it back tomorrow afternoon.

The block checks within spec for flatness. A 0.002" feeler gauge blade will not fit underneath the straight edge at any point.