Backstory: Wife always wanted a S2k when she was younger and finally got one. '03 AP1 looked a little rough but she ultimately wanted it. Bought and drove about 300 miles home no issues. Couple months later it suddenly started overheating. Burped air several times. Coolant level progressively started dropping with no leak. I compression tested the motor and it was good across the board. Saw oil sludge in her overflow. Did Blackstone oil analysis and they saw coolant in oil. I told her stop driving it and I would help her out.

Now, I pulled the head off, cleaned her engine bay of gook and found some issues. Previous owner clipped the injector clip and soldered wires directly to the injector. Also I'm guessing he was running a piggyback because all injectors had taps on them. I'm going to replace all of them with fresh clips. New HG + bolts x 10, valve cover + spark plugs and gaskets (leaking), Billman TCT (terrible TC rattle), new plugs, thermostat + gasket (precautionary), flush rad/hoses.

Was going to scrub some carbon off the valves but leave the pistons alone since I don't want carbon scorring walls. Anything else while I'm in here that I should do? That intake manifold was terrible removing. I never want to see this car again in my workspace, lol.

 

Here's before I got the bay cleaned up

 

No warpage in head or block surfaces?

Good luck with fix!

 

Check the block and head for flatness, especially in the area of fluid penetration. Hope you got OEM parts and not ebay.

 

Checked both head/block as per spec <.05mm, checks out. OEM parts minus the thermostat (Mishimoto). Head's cleaned up, oiled, and sealed in a bag until parts get here...just waiting.

 

Do you know what caused the oil-water leak? Head gasket blow?

Seems that the valves on number 1 cylinder were changed-out, in the past. Do you think this related to the pressure leak?

Thanks!

 

Did you replace the valve retainers? Might be a good idea for preventative maintenance since the head is off and will be much easier.

 

I guess I would want to have a clear idea how the water got in there, and why it got in there, before I put it all back together. I'd want to know the root cause.

 

Didn't notice this, how did you spot this? The intake valves look marked slightly different. That could be it related to the leak. Good catch

Someone else had just mentioned that to me, it appears Ap2 intake retainers were redesigned and are better for high rpm load? I told the wife and she ordered a set of 8 ap2 valve retainers and 16 new keepers. Also if you look at the 11 o'clock position on one of the retainers for intake cylinder one--there's a slightly crack on the outer edge of the retainer. Which is weird because the forum guys seem to mention it cracking from the inside of the retainer around the valve stem rather than the outside.

I'm speculating a lot but haven't quite figured out why. I have a feeling the past owner supercharged this car and then it was returned to stock. How that relates to now I'm not sure.

Thank to all for the feedback

 

Also I don't consider myself the s2ki expert by any means, but on cylinder 2 it looks like one of the intake valves is "sunken in"--meaning it could be cracked. I'll be taking them off soon to inspect. Hopefully I don't find any crazy surprises.