Hey everyone! I’m doing a timing belt/water pump and head gasket on my new-to-me ‘99 EX (D16Y8 VTEC) and after pulling the head, I found some tiny metal shavings on the top of pistons 1 & 2 and in the coolant channels, along with some burring on a few surfaces in the channels. The old water pump looks perfectly fine, nothing broken on impeller. Head surface doesn’t look gouged, just dirty. I plan on checking surface with a straight edge as well.


Here’s some photos:

You can see the metal flakes on the piston head, along with the burring on the outer surface of the coolant channel. All burring is inside of the block, not on any mating surfaces.





More burrs on the inlet from the water pump into the block


What looks to be either sediment or pitting in cylinder 4 coolant channel



Kind of hard to see, but the head surface above cylinder 2 has more residue and moisture around it, mostly on the exhaust side.


At this point, I’m thinking that it’s likely the previous owner had a water pump go bad, and a piece of the impeller broke off and made its way through the block. I also pulled the thermostat and it looks fine, save for the torn up rubber, so I’ll be replacing that as well.

Any thoughts, you guys?

 

Started cleaning the deck to prep for the new HG and found this as well:




Looks like a small crack in the oil passage right above where the A/C idler/adjustment pulley mounts to the block. Is it something to be concerned about, or nah?

 

Have you scraped off any of that to see what it is?

 

I was able to wipe some of the sediment out of coolant channel next to cylinder 4 and it looks like carbon build up, maybe? I ran my finger along the burring next to cylinder 1, it’s hard and was sharp enough to cut my glove open, same with the inlet from the water pump

 

The rough edging around the passageways are just something you'll find due to casting process. The build up in the coolant passageways is probably calcium buildup from the PO using more water than coolant. It needs to be a 50/50 mix of coolant and distilled water. Or buy pre=mixed coolant and not have to worry about mixing it.

 

The burrs on the castings are quite normal, the only way material is going to get onto your piston is via the intake valve opening, so I would be looking at the intake manifold / throttle body / air intake setup. Quite amazing that any material stayed in there considering the exhaust opens anything in the hole is ejected?