Hi Bob,

Actually, I find his comments right on the mark. He's described the function and failure of the hybrid that causes the 561s 90% of their bad reputation, as much as my experience and probing has revealed.

LH-fixer's perspective appears a bit wider and global compared to our LH2.4 experience in 86-93 240s, so might appear more mysterious than it is. The degradation of the hybrid is the same process I believe mostly responsible for the AMM problems, perhaps, but not fully, abetted by those airbox thermostats that only last a year.

I've found the hybrid design was changed sometime during the 561's production - the later being the same as that used in the "rock-solid" 951. So there actually are some 561's worth keeping. I haven't had enough of them to know how to identify them from the outside, but I have some closeup photos of the hybrids useful in recognizing an old from new.

So, I guess, the good news is there's a way to tell, but you have to open the box if you use my method, until I learn how Bosch identified their in-model revisions.