I recently warped my head on my NA. I got the head machined flat and a new head gasket. I started it up I had a turbo oil feed leak. No biggie, just gotta tighten the fitting. Turns out, all that oil that was leaking out was all milky and chocolate milky like. I drained the oil and all of it was contaminated, looked like coffee. Coolant also looks like it's contaminated (I'm running straight water right now). I'm trying to figure out what the issue is.

I torqued the head bolts to the proper spec, reused the bolts. I did not have any coolant oil mixture issues when the head was warped, so I've somehow made the issue worse. On startup, my ignition timing was wayyyy off, super retarded timing. It was like 30 degrees off or something. During cranking (my battery also died) there was a huge backfire incident, shook the car and everything, very violent event, like it was LOUD, maybe that could be related to something. I've got the car to idle fine with the tune. There is no smoke coming out of the exhaust sooooo

I just pulled the head again and the head gasket is intact and there look to be no cracks in the block. I've also pressurized the turbo CHRA coolant lines with like 20psi of air and there is no air leaking out of anywhere. Anything with the stock oil cooler/warmer could be wrong? Cracked head? Maybe I just need new head bolts? I was under the assumption that I could reuse those but maybe not.

I'm stumped, any ideas?

 

If you didn't pull the block prior, there's a good chance that there's still a lot of froth / water in the block from the prior incident. If you want to be sure, you can also grab a coolant pressure tester from autozone (unfortunately they raised the price from 80$ to 200$, but it's a rental so you're not actually losing mone) and see if the coolant system will hold pressure or leak it into the block.Head bolts are torque to yield and not reusable iirc.

 

Yeah, I was thinking maybe there was leftover residue, but I changed the oil twice and on the last time the oil was just super thin (I'm running straight water). I'll go and test the cooling system once I put everything back together again. I've heard mixed things about the head bolts, was just trying out my luck, maybe they are the issue tough.

 

Miata head bolts are absolutely not torque to yield and are reusable. I did plenty of research before reusing mine and they've been torqued at least 4 times now.

It's too late to do any troubleshooting since the head is off but my bet is a botched gasket installation. Go over the service manual procedure and make sure you didn't miss anything.

 

Yeah, I'm hoping it was just an installation issue and nothing huge. The biggest concern during installation was probably figuring out which way the block dowel pins went, I'm still unsure which direction they sit in the block.

 

i reused my oem head bolts on my rods/bearings engine rebuild, and the new oem head gasket is working perfectly fine.

are you using an OEM gasket?

 

Yep OEM, from Fab9. Its the 94-97 gasket, with the coolant passages on the front of the head.

 

What do you mean by dowel direction?

 

Im pretty sure it doesn't matter, but there's those dowels that sit in the block to align the head and head gasket. One sides notched and one sides tapered so I figured maybe there's a certain direction these things go in.

 

Head is not warped, did not check for cracks yet, but I'll do that in the end. I don't feel like paying $80 for a pressure test right now when I can test other things for free. Also, the oil cooler is intact. Is it possible that I warped the block? The guy at the machine shop said thats possible, I'll try and find a straightedge and test it.

 

If you didn't warp the head, you didn't warp the block. The dowels go in either direction.

 

It was warped about a month ago. The head warped about 0.004"-0.005". I just got it machined down flat and put it back on with a new head gasket. That's when I started having this issue.