Jump to content
SAU Community

Recommended Posts

Hey guys. My RB26 block trickles water out the front behind the front cover when I put water in the radiator. I have pinpointed it out to be in a certain area of the front of the block, and it appears to be from a circular plug of some sort on the block (not a freeze/core/welch plug). I was wondering what this circular thing is, and is there a way to fix it? It appears to have a circular tooling mark like it was pressed in. I am not sure if it popped out or not. If I touch it by finger, it feels really solid and doesn't move. The water comes out at a rate of about a shot glass every 5-7 seconds or so. I have concluded that it is either a crack or this circular thing that is releasing water. I can't visually see a crack (unless it is hiding in that rough casting just below it). Any help figuring this out would be much appreciated. At worst case, I will need to purchase an N1 block and get it bored to 86.5mm to swap my 2.8L bottom end into. I am really trying to avoid that at all cost right now, so I would like to exhaust all avenues and options before pulling the motor for the millionth time.

IMG_20151017_183533.jpgIMG_20151018_160637.jpgIMG_20151018_160143.jpgIMG_20151018_160621.jpg

Link to comment
https://www.sau.com.au/forums/topic/460437-rb26-leaking-from-block/
Share on other sites

Well, it could be the plug. I don't know if there's oil or water behind that one. Assuming it's water, then, certainly any of your theories could be correct (those being the seal of the plug itself or perhaps a crack in the block).

But here's the question. The water isn't coming from the water pump below and squirting up and fooling you as to the source?

I leak tested this setup by removing the timing covers, timing belt, tensioner, and idler, then reinstalling the radiator. I poured water in the radiator, and shortly after, it would begin trickling out from below the water pump. Along the bottom perimeter of the pump was dry when I touched it with my hand, and the wetness definitely began a little lower, but I couldn't get at a good enough angle to see it. In order to view the area better, I took the water pump off. The problem with the pump off is that I can no longer test for the leak, since water will just come pouring out the openings instead. All I know is that it was this general area in question, and I wanted to know if anyone has ever had this problem or even knew what this little circular plug looking thing is. I can try putting the water pump back on and have someone hold a phone down there to record the area while I pour water back in. Either way, if its that plug thing, how do you remove it or reseal it? I am just trying to get a game plan for it if that's the case.

It would come out and go back in the same as any other welch plug, even if it is a bit different in design to a real welch plug. Drill hole in centre and use big fat self tapper thread on a slide hammer to get it out. Clean up hole, put sealant on new one and push it in. Probably easier to do with engine out than in, but surely not impossible to do in car.

Edited by GTSBoy

Thats a oil passage bung, you remove it to clean the oil galleries.

Edit, same bung is in the back of the block so you can get a rifle cleaner through there....

Id say your leak (if water) is coming from the pump above.

Edited by GTRPSI
  • Like 2

Thats a oil passage bung, you remove it to clean the oil galleries.

Edit, same bung is in the back of the block so you can get a rifle cleaner through there....

Id say your leak (if water) is coming from the pump above.

im glad someone said it
  • Like 1

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

    • I dunno. I just go off what I know works. On RB20, the idle switch meant something to the ECU and the potentiometer was ignored. In Nistune, with the switch unplugged, you could bridge the terminals in the loom connector and see IDLE come on and off. Not so by moving the pot. The R32 RB20 ECU and the 26 ECU both look like this. Sure there is the "throttle sensor" (pot) on pin 38, and also sure, the idle switch is also directly wired to the TCU, whereas the pot is only directly conected to the ECU. But I am sure that the throttle position from the pot is passed to the TCU across the data bus on pins 21, 22 & 31. Maybe the ECU likes to know throttle position, but it sure as hell doesn't use it to determine the idle condition. Meanwhile, on the later engines, like the 33 25DET and my Neo, you remove the TPS and move the pot to-from the 0.45V position, and IDLE comes and goes in Nistune. No throttle switch on the ECU diagram. Just the pot.
    • So, good news and bad news Bad news first: The intake plenum is lost in the mail apparently, I haven't paid for it yet, and MX5 Mania are still chasing it up, farking 'Merica postal service  Good news: Any retune will be free if and when it turns up,  I'm still keen for them to throw it on The car goes noticeably better, with only the typical initial take off thingie from a choppy cam and manual transmission, but giving it just a little more RPM than before gives it a smooth take off (and hour or so of peak hour traffic sorted that little skill out) Car made around 145kwatw & 225Nm (Intake may get me to 150kw, maybe....馃ぃ) Weirdly, 145kwatw is the same max power that my standard 2015 WRX STI made a few years ago The cam really comes alive from around 3.5k and keeps making power and holds it flatish all the way to 7k, whereas before torque would drop hard around at 4.5k Drive home was sadly in peak hour, although I did get a little clean air here and there to wind out 1st and 2nd a little bit, and whilst the gains aren't anything for the "boosted boys" to be impressed at, the thing is a blast to drive The sound in the vid is poor, as it is in a undercover yard at work, but, outside, in the wild, it sounds awesomeballs to my ears with all the choppyness I consider it money very well spent for the outcome  Cam specs for reference (Basically the biggest you can fit with stock pistons) 20250417_171807.mp4   LOL, I don't think I will ever grow up  
    • Swap the injectors around and see what happens. If the misfire follows the injectors then that's a signal, if it doesn't it's probably not the injectors.
    • R33 with RB26 seems to go off of learned voltage for idle. Seemed like whatever the baseline voltage was once ECU first gains power will be the idle voltage. With ignition on unplug/replugging the TPS would relearn the idle TPS voltage.
    • Have you confirmed the 2 pin coolant temp sensor on the motor is working properly? I've had a very similar issue when I forgot to plug mine back in many years ago.
  • Create New...