Water in oil. compression still ok
 

Last Saturday when I was driving on track my car start to hesitate. I wasn’t overheating (water was 220F and oil 230F). When I open the hood I notice that my catch can was overflowing with oil.

• I check the compression. 173-170-169-175. Stock 8.8:1 pistons 100K miles driven. I got same compression result year ago.
• Oil-stick is full of milky cream
• Top of the catch can is full of (condensed?) water
• I fill up my radiator 500miles ago and look like there's about half a gallon shortage now
• I’m using 250cc/min water-injection but sounds odd if that water got past the rings

Sounds like head gasket has gone bad. But why my compression results looks the same as when i didn’t have these problems?

If oil is blowing out it has to be high pressure in cylinder head right? Compression seems to be ok. And only 5-10psi higher with drop of oil so I assume that rings are ok.

So that leaves the head gasket or loose cylinder head bolts. Guess I can re-torque those bolts or maybe better, change ARP bolts there.

check your cylinders for cracks :D mine had good compression, and oil/water mix

mine HAD good compression, and coolant in my oil.
also founded that ''water/coolant'' in my catch can.
cracked cylinder head for me

Well let’s hope that isn’t the case. I just bought that head and had that checked for valve leaks.

I did compression test again with drop of oil. Wet results were about 8-12PSI higher so it is probably the head gasket. Why can’t my car run even a month without problems :vash:

dont be that disapointed, changing it takes about 3-4h

i installed a 150$ cometic head gasket with 100$ worth of bolts after going to make sure my head was straight. it sure was straight....and cracked.

Cylinder head is off and I didn't found cracks or anything unusual. Guess if I want to be sure I have to get that leak-tested again. But I’m almost sure that cause of all this is my old head bolts which I been re-using over 6 times by now :giggle:

Here’s a picture of water injected head: http://www.miata.fi/kuvat/head070711.jpg
Exhaust valves is covert with that “hard white stuff”

Did you found that crack looking it? Or can those cracks be so small that eye can’t see it

could not find anything just by looking at it, i did not extended my search too long since b6 are so cheap i ordered another one for next-to-nothing.


I went to a shop that did a leak down test, told me i had a cracked head, and i drove home just like if i stole it.i'm curently getting the engine out

A little update: I change the HG and replace those old bolts with ARP stuff. Start the car. Had it run 15min. Tested compression again and it changed from 173-170-169-175 to 195-190-185-175 PSI

while installing the new engine i founded the mo-fo who was fucking everything up
https://www.miataturbo.net/attachmen...ine=1311427293

It’s probably safe to say that this problem is now gone. It was bad head gasket or the head bolts..or both.
Coolant level has stayed the same and same goes with oil :) And car pulls hard