Likelihood of Honda Civic cracked engine blocks?



What percentage of 2006-8 Honda Civics develop a cracked engine block (aluminum)? I love my 2008 Honda, but reading about this possible defect worries me. Any preventive steps to take? Am I worrying needlessly? I miss the NPR Car Talk show!


Honda extended the warranty for as much as 8 years covering the coolant leak, so if you go to your local Honda dealer you could get the engine block or even the entire engine replaced free of charge (if you have a coolant leak).

There is nothing you can do, proactively to prevent it. Just keep an eye out for leaks. On Car, there were 48 cracked engine blocks of 596 complaints filed of about 400K cars sold. Pretty darn small!


I don’t think Honda even knows what PERCENTAGE have cracked engine blocks. As others point out, Hinda has been normally good at issuing extend warranties for covering manufacturing defects.


Do what you can to avoid the engine overheating experience. A single overheating experience can crack the block. Monitor the dashboard coolant temperature gauge, and if it ever behaves abnormally, even if it isn’t overheating, even if it is lower than normal, get the car to the shop. Put a mark on the gauge where the normal operating temperature is. Monitor the coolant level, and replace the coolant with Honda approved coolant every 2 years. If there’s ever any signs of coolant leaking, get that corrected right away. Make sure the engine compartment fans are turning on when they should and doing their thing. Does your car have an audio alarm if the coolant gets too hot? If so, and you hear an alarm, pull over and turn off the engine asap. If it is only a visual indicator for overheating, ask around if there’s a way to install an aftermarket audio alarm for coolant overheating. And if you get an overheating experience even after doing all this, don’t try to cool it off by pouring cold water on a hot engine. Just let it cool off by itself.


I just bought a 2006 Civic 1.8l and was wondering the same thing. Honda sold over one million Civics in the affected years 2006 - 2008^ and there are 289 total complaints on carcomplaints, something like a .03% defect rate. Yes not every cracked block is being reported but it’s a big enough deal so that quite a few would be. But even if you said only 3% are being reported that’s still less than a 1% defect rate. And only 9 reports so far in 2018 so you get the feeling most of the weak blocks have already failed and been dealt with so your chances of getting a crack are pretty slim now over 10 years in.

At any rate after doing a little research I’m not that concerned. I still see a TON of 8th gen Civics rolling happily down the road every day so I’m guessing these cracked blocks are highly unusual and small in number. Most owners probably aren’t even aware there’s an issue. If Honda had to replace a million engine blocks they would go bankrupt and they seem to be doing just fine. Non-issue.

^Yes I know a handful of 2009 were included in the TSB. Only one complaint on carcomplaints so I left it out to keep from making the defect rate look even smaller.