Jump to content
SAU Community

Recommended Posts

hi guys a few months ago i started seeing moisture vapour coming from the rocker cover breathers. The hoses go to a catch can, i put one into an open plastic bottle to keep an eye on it. I thought it may be a leaking headgasket as there were lots of tiny bubble in the radiator. I put in some seal up and that seemed to fix the problem.

Now it has come back again and i noticed the car isnt as responsive now but still idles fine and goes good on boost. There is only the moisture coming from the breathers not oil. I dont think its blowby and the plastic bottle a breather hose goes into only gets a slight amount of a sort of watery oil film on the inside, no great amount.

Anyway i did a compression test yesterday and here are the results.

180 psi in cyl1

180 psi cyl2

180 psi cyl3

180 psi cyl4

130 psi cyl5

155 psi cyl6

Doesnt use oil, maybe half a litre between 5000km changes.

Engine is fully built with cp pistons, eagle rods, cometic headgasket, arp headstuds. What are your guys thoughts? Should i change the headgasket or does it sound like something worse?

Link to comment
https://www.sau.com.au/forums/topic/378249-compression-dilemma-on-built-25-neo/
Share on other sites

Do a leak down test.

Also, put a little oil down cylinder after you test it and test it again. If te compression doesn't come up after the oil, then it's not the rings, but a head gasket.

Sounds like a was gasket if there is water amongst the problem.

Tis is the first comp test. I put a cap of oil in and the results only came up around 5 psi on the low cylinders. Run on full synthetic motul oil. The only issues are as stated in first post.

The plugs were dry when i took them out to do the comp test.

I thought it may be a leaking headgasket as there were lots of tiny bubble in the radiator. I put in some seal up and that seemed to fix the problem.

Now it has come back again

Classic head gasket symptoms. You can get your radiator "bubbles" analyzed for about $25 to see if its leaking exhaust gas into it. Then you know for sure.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yeah so N1 and any other larger than factory pump are pretty famous for pumping the sump dry...obviously we don't often get to spend 20 or 30 seconds at high rpm/full noise on the road so I'd still be suspicious that is what is happening here.
    • You are also getting pressure dips on gear shifts. They're just not dipping as far, but they're dipping quite below the amount of oil pressure you should be seeing, for how much RPM drops.   It quite little could be the oil pressure relief valve is starting to stick open a little/is slow to close.
    • Can you log battery voltage, and TPS, and put all four of those into a single image (even as split graphs)?   The oil pressure drops aren't following RPM as such. I'm intrigued if you may have a ground loop between different sensors. With the engine not running, log your sensors and for example cycle the throttle pedal. See if any sensor values flutter or move about. This won't be a perfect test either as the ECU won't be cycling all of its actuators like it would be while running. What EMTRON do you have? Do you have a link to the wiring guide for that ECU?
    • What logic functions do you feel are missing from the Haltech that others have? Is there a limit to how much logic you can string together? By limit, I mean it's like only a single level or two levels of Boolean logic. Realistically, AND, OR, and NOT, is really the only logic you need and realistically, you can also do away with another logic gate of the three above . With those three you can build the full functionality of any Boolean logic you want.
    • Well that rules out the relocation theory, however with no load, you're still getting 1.5bar of oil pressure. Can you present that data in a scatter graph over longer period? Would really highly the anomalies. Wish Haltech could do that.
×
×
  • Create New...