I was at a used car dealer looking at a 2007 civic LX Coupe, saw what appeared to be white staining on the aluminum engine block . couldve been water staining or a corrosive substance. The two nuts near the stain were white in color as if painted or stained as well. Should i be concerned? what could it mean?

 

where exactly on the block was the stain? around where the headgasket would be? i believe there is some sort of recall about something happening to r18 engine blocks.

are you buying this from one of those car dealerships on the corner of the street? never buy from them. almost a guarantee there is a problem with the car.

 

I would defiantly bring it to the attention of the dealership and have them look at it and make sure that it if it is a problem they are going to take care of it.

 

It's very possible that the engine block was leaking coolant. There is a 8 year (no mileage limit) warranty extension on 06-09 civic blocks due to improper block casting, that can crack and leak coolant. However, i would probably stay away from it.

 

Where are you located? In my part of the states, salt water and snow will splash up on your engine and stain just about everything white.

 

They don't crack, the casting is actually porous. Generally the staining will be kind of a green white. Take it to Honda and mention it to them, it may help if you have a copy of the TSB with you when you do.

 

They actually do crack, usually in the middle of the block running horizontal spanning an inch or so. Regardless, it is due to a casting flaw and you're right, most coolant "stains" are white with a green tint.

 

sure does look like a crack but Honda uses politically correct, non-customer enraging words like "porous casting" just like GM uses "thermal event" instead of "catch fire"

but yeah, the aluminum is too thin along the coolant passages and it "cracks" you can tell they aren't "pores" because you can see the crack by spraying brake cleaner on it and watching it evaporate, revealing the crack

 

stain located behind the exhaust manifold half way's up the block? this is the most common spot too see the crack or "porous casting"

 

If he's right and got engine block replaced, it's brand new block. Ask them and check service history. It's a hard call. You might getting a new block. But then again, depends on who did it, it could be a good job or bad job.

 

if its been to the dealer lately for service, chances are they sprayed a "developer" on the block because they suspected a leak of some sort. the spray makes it easier to tell where a leak is coming from. as far as the engine block cracking, the blocks were casted poorly making them thin and possibly porous. this leads them to cracking in small places, in which you will loose a ton of coolant. if the block cracks its pretty easy to tell because most of the engine bay will be covered in coolant.