Cracked Engine Block

Should the engine block of an 2005 Acura RL crack if the car’s maintenance has been regular and complete according to all dealer specified recommendations? Cooling system never stopped working either. What else could cause the engine block to crack?


If the engine was out, dismantled, cleaned and the pieces on a table MAYBE someone could make a SWAG as to the cause. Of course freezing due to lack of anti-freeze in the cooling system is the most common cause for cracks in the water jacket. But over the years there have been many engines that were introduced and remained in production several years before engineering errors were recognized due to failures on the road. The early Chevrolet 2.8L engine comes to mind. That engine was prone to crack in the lifter galley where oil would get pumped into the water jacket.

Some Honda engines of that era were cast with defects, thus making them “porous”.
Acura=Honda, so I wouldn’t rule out a defective engine casting as the source of the problem.
However, getting Honda/Acura to admit to this problem is another issue entirely…

The super cold winter we’ve had coupled with the fact that an older vehicles may easily have older antfreeze not quite down to temp specs nor renewed anytime in recent memory…could have contributed to a freezing episode somewhere along the line.

The highest probability is a freezing event.
However, without doing a failure analysis, perhaps even with a SEM, it’s impossible to guess from here.

Should a block crack? No.
But humans do things to their machinery that subject it to conditions it wasn’t designed to withstand .

I agree. Blocks can crack for a variety of reasons, some of which have more to do with defects during manufacture then maintenance. But, of it happens after the warranty runs out, you are at the mercy of the maufacturer.

Heavy collision is another possibility if this car was stuffed.

Thanks for the input. No collisions, antifreeze was changed at recommended intervals. VDCdriver, do you have a reference for this information that some engines were cast with defects in that time period?


What evidence do you have that your block is cracked, @rustylogic?

+1 to @Rod Knox. Who says the block is cracked. I’ve heard that line of baloney many times, and mostly it’s not true. Now, the head might crack, but the block is unlikely to crack with reasonable maintenance. So, if a mechanic is telling you this story, you might want to look in the “mechanics files” at the top of the page for a second opinion.


There were some Civics a few years ago, 2006-2008 models, and even some 2009 models, that had cracked blocks

Honda officially fessed up, and extended the warranty on the blocks

I’ve personally seen one of these cracked blocks. It was a hairline crack, but coolant was seeping out

OK @db4690, if that’s the case then maybe someone here knows how to find a service bulletin to give @rustylogic some ammunition.

Rusty, I just Googled “cracked Honda engine blocks” and there’s tons of “hits”. I’ll leave it to you to Google the info and sort through it. I hope it helps.

An engine block – like any piece of cast iron – can crack for no apparent reason. Not a common thing fortunately. The block starts out as a mold, then molten metal is poured in, and allowed to cool. If the molten metal is contaminated, or it doesn’t cool off slowly enough or unevenly, stresses can develop from which a crack can form, sometimes much later. After the casting is cooled and removed from the mold it then undergoes a lot of machining, drilling, etc, and if it is too roughly handled that can induce cracks.

If you have a chance to see it, sometimes PBS airs a show about a company that manufactures cast iron pots and pans. At one point they show a huge pile – like 20 feet tall – of them sitting outside, waiting to be remelted and cast as new. They said some in that pile were from defects pulled from the production line, but others were returns from people who bought them, then later they cracked and leaked, so were returned to the company for replacement.

I’m fairly certain OP’s engine has an aluminum block