Back of the block

 

The green one is your oil pressure sensor.

 

Would be nice if you told us which engine it is. Since I don't see a spot for a knock
sensor, and you say it's a D16, I guess it's a D16Z6 (or whatever they call it in
Germany).

And jbpnoman is right, the green sensor is the oil pressure switch.

And the other hole is not used IIRC, someone correct me if I'm wrong here.

 

pic of my Y8

My block has a plug in the 2nd slot in question. The Z6 in my car is the same way also.

 

what they said for the green one you usually replace that when going turbo for ur turbo gauge and the other one isnt that to drain the block as well?>

 

Actually you just tee off of it. It doesn't actually get replaced.

 

oh my friends replaced his cause it came with his gauge

 

Is that a d16y8? its sitting right up against the cylinder like its a hole for a knock sensor or somthing? :UPDATE:Yup its a knock sensor The D16y8 came with a knock sensor and a crank position sensor and the D16Z6 did not so Im assuming thats a D16Y8. but its not in the same location as yours on your block so im a little confused??

 

Green one is a oil pressure switch. The other is unused. Obd0 block.

 

Pretty sure it's Z6 block. The OBD0 block actually has threads in the second hole for the fan switch. See this link for comparison
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/how-d16z6-block-d16a6-head-2754616/

 

Same here, or the European equivalent.

Definitely not a usdm D16Y block.

 

Yeah the block does look a little different from a US block...

 

I believe theyre for knock and oil

 

well OP is from germany but they also have the z6 in europe so idk.. would help if op responded

 

me too..

 

I think he may have borrowed the pic from google

https://honda-tech.com/forums/forced-induction-16/stock-oil-cooilng-d16-block-2820019/