woodly1069

Hey guys I'm sure this will be an easy question for most but since I am a noob I thought I would post this question. I just got around to pulling the head off my 2000 Civic cause it has been loosing antifreeze slowly. No drips, smelled like it was burning it in the combustion chambers, (smell from exhaust). My question is this, the cylinders look as if there is silver coating missing in spots. The bores are still smooth as glass but it looks odd to me. The car never smokes or uses oil so I am not sure. Did Honda use a Nikasil coating or something in the bores from the factory? Is this something to worry about? Head and block look OK and I don't really see where the head gasket would have been leaking internally...thanks for any thoughts!







Please keep in mind that I just pulled the head 15 minutes prior to these photos and what appears to be rust is not, it is totally smooth. This is why I posted the question the way I did about the Nikasil plating...

ezone

Kinda looks like it's starting to rust......
from being opened up and left alone too long, or from the steam cleaning action of burning coolant taking the oil film off the walls.

Wipe the exposed cylinder walls with engine oil. (I dip my finger in the oil and smear it all around.)

woodly1069

Actually I took that photo 15 minutes after pulling the head so I am leaning towards the the steam thought. How about head gaskets blowing, since they are steel how would you know where it was leaking?

ezone

IDK what the discoloration is, I was guessing.
I'd roll the crank so I could see and inspect the other 2 cylinders and compare.
Wipe the cylinders with oil before they rust.

The time to figure out which cylinder WAS leaking was before the head came off. Now all you can do is look for the evidence, and a steel head gasket usually doesn't show much evidence unless it was a really serious breach.

If the engine was overheated, either before or after the head gasket let go, then the head is likely to be warped. When a head warps, it usually lifts up in the center, so the coolant (and/or combustion) leaks from the 2 center cylinders. But that does not mean the problem started in the center cylinders.

The head needs to be inspected no matter if you witnessed it overheated or not.
Have the head measured for flatness, at a machine shop if you don't have access to a precision straightedge and feelers. I think .002" is the max warpage allowable (did not look it up). If the head isn't perfectly flat, a head gasket job will not last.

woodly1069

Thanks for the heads up ezone, I really didn't expect to find the head gasket to be metal but you live and learn. As for the #1 and #4 cylinders, I did roll the crank back last night to check them and they don't look as bad as 2-3 but there is still evidence of the copper color. I did as you mentioned and soaked the cylinders down as well. Oh yeah, and you are also right about them being iron, they have a strong attraction to my shop magnet.

It is going to the machine shop this morning!