Thinking back to the falling rocker arm problem of a few years ago, it's my recollection that there were only a handful of anecdotes (fewer than ten) posted by people who actually had that problem occur on their car. I'm pretty sure I've seen a lot more anecdotes about cracked cylinder heads.
The rocker arm problem resulted an apparently voluntary recall. I'm not holding my breath until there's a recall for the cracked cylinder head vulnerability.
It's hard to assess the relative safety hazard of the two defects. Both are rather low; neither is negligible. The more obvious difference is that addressing the rocker arm problem was cheap for Mazda--just reprogramming the PCM. Fixing the cracking cylinder head problem would be extremely expensive, probably thousands of dollars per car.
I hope many people who have experienced a cracked cylinder head will
file a safety complaint with NHTSA, resulting in a mandatory recall.
To add to your post...
One could argue the Toyota accelerator problem was a negligable or low safety hazard... after all it's just a sticking pedal...93 deaths out of 4 million vehicles which is only 0.0000233 percent. Still unacceptable. Until the deaths started piling up, no one knew there was a problem because the isolated incidents were kept quiet.
Awhile ago, was a passenger in a vehicle(older vehicle at that) which the engine seized on a 6 lane highway. She luckily was in the right lane when started having problems but people always think they can make it to the next exit...it's human instinct.
When the engine seized almost immediately thereafter she still barely made it over to berm before the vehicle stopped in travel lane and/or barely got clipped by 65 mph and up traffic(after all there are speeders).
We would have been rear-ended for sure if had been in the far center lane. No way would have gotten through traffic and over to the right shoulder.
Granted that occurred on a very old high mileage vehicle. But major engine crack and leaks definitely should not occur on a newer vehicle and imo should not even occur on anything less than 10 years/150,000 miles.
The whole reason one buys a new or dependable used vehicle for $25, $30, $35 k is to drive without fearof major problems or being stranded.
If I wanted a car that the engine might crap out, I'd just weld the frame on my 14 year old vehicle and drive that around waiting for that dependable (up to now) engine to finally give out.
According to some posts, some of these vehicles are losing drastic amount of oil and coolant which could quickly become a catastrophic failure within minutes including stalling in high speed traffic.
People panic when lights start flashing, car sputtering and/or slowing and engine stalls. Berms are not always ideal with all kind of objects on the shoulder. The mind takes time to assess whats happening. Cars and big-rigs whizzing by at high speed. If your stuck in the center lane, you're potentially doomed to be a multi-car pileup.
Add to that the indirect danger of getting hit when someone not paying attention swerves onto the shoulder which happens alot more nowadays because some people are texting and not paying attention.
Same for an 4 lane highway, the same risk is still there, especially if caught in middle lane with 18 wheelers flying by.
Others here might not think its a big safety issue until it happens to them or until a death occurs.
Of course, the odds are lower because it's a smaller manufacturer with less vehicles on the road, with unknown percentage of failures and only some of those failures may leak enough to potentially engine sieze while driving on an highway.
But it is still very much a safety related issue.
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