Jump to content
SAU Community

Recommended Posts

Ok i have done a search, sounds like my cooling system may not be bled correctly.

Recently installed a new waterpump & fresh tested / cleaned radiator for my 26.

The car does not overheat at all when driving, however after stopping the overflow bottle starts to boil after a little while.

I filled up the coolant correctly (removed bleed screw etc) however to get the remaining air out it sounds like i may have to undo this bolt again when the car is hot / boiling after i stop? Just want to make sure this is safe enough to do.. or perhaps there is another way?

Link to comment
https://www.sau.com.au/forums/topic/325735-coolant-boil-bubble/
Share on other sites

Cut the base off a coke bottle and tape the smaller side opening to your radiator filler (when cold). start the car then start tipping water into the coke bottle till its half way full and let it idle for a while.. it should bubble up releasing the air..

Cheers

Johno

Cut the base off a coke bottle and tape the smaller side opening to your radiator filler (when cold). start the car then start tipping water into the coke bottle till its half way full and let it idle for a while.. it should bubble up releasing the air..

Cheers

Johno

+1 thats the way to do it, just keeping filling till you get water coming out of the bleed screw.

probably not best to do when fully up to temp if you aren't confident. if you do decide to do it, have a rag wrapped around the area, or at least sitting over the top of the spanner. also you don't want to remove the bolt the whole way. you just want to loosen it enough that any air can escape, so you probably only need to loosen it a few turns. you will be able to tell once you are starting to get close to having it completely undone as the last few turns the bolt will be a bit wobbly in the thread, and also you will get coolant making it's way past the thread. the moment you get coolant starting to seep out then you don't need to loosen it off any further.

however i would do it when the car is only just coming up to temp. i wouldn't be doing after driving the car round for half an hour.

Cheers for the help. I bled it with this method this evening, took it for a drive - problem is still there when turned off!?

It doesn't go above 82 degrees whilst driving, even when giving some boot.

I am thinking that it might be corrosion in the cooling system? The radiator is clean as a whistle but inside the radiator pipes on motor side doesn't look too healthy. I have some cooling system flush on the way so will give this a whirl and see how i go.

I suppose the only other thing could be air getting into the system somewhere... in another thread someone mentioned the turbo water supply/return hoses.

Could it be anything else?

it is very hard for air to get into the system, because the system becomes pressurised when hot, so any places air could get in will have water squirting out of them. only real cause of air bubbles can be a dodgy water pump causing cavitation resulting in bubbles, or a blown head gasket.

it may be worth replacing your radiator cap and see if that makes any difference. just go a standard cap with the same pressure rating.

Yeah was also thinking the radiator cap. Always easy to overlook the simple things!

Replaced it last night - boil is gone :)

I heard a couple bubbles when it was cooling down. Probably just crap left over in system, getting engine flush next week.

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

    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
    • Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.
    • In my head it does make sense to be a fuel problem since that is what I touched when cleaning the system. When I was testing with the fuel pressure gauge, the pressure was constantly 2.5 bar with the FPR vacuum removed. When stalling, the pressure was going up to 3.0 bar (which is how it should be on ignition).
×
×
  • Create New...