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M42 Coolant Bleeding. Beat to Death I know.

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    M42 Coolant Bleeding. Beat to Death I know.

    I'm at a loss for what to do on my 318 overheating after major repair.

    Ok, here's the story. I have just recently put on a head and refreshed all the gaskets on the M42. I have replaced the water pump, thermostat, and radiator. I have done the mess under the intake fix. The PO had looped the heater core due to it leaking, and I haven't replaced it yet, so I have run a hose from the large rear port on head to the rear of the plastic coolant pipe. I have run a hose from the small head port to the plastic coolant pipe as well. The middle port on the plastic pipe runs to the bottom of the expansion tank as before. I've got a working electric fan hooked up to a manual switch for the time being.

    My procedure so far:

    Jack up front of car.

    Fill expansion tank with bleed screw removed, and keep filling until no more bubbles come out of bleed hole. Suck out water until back at cold level mark.

    Start car and run until gauge is @ 1/2. Upper hose is hot, lower hose is warm/hot, thermostat is open.

    Rev up to 3k, open bleed screw...no coolant even close to coming out. I can squeeze the lower hose and get a little spray, but nothing when engine is revved. The expansion tank level does drop a bit when revved, so I am pretty positive the pump is working.

    No flow of coolant is coming out of the little hole under the expansion tank. Every BMW I've ever worked on streams out coolant from the hole under the cap when revved. Which I have never seen before.

    I hooked up my pressure tester to the ex. tank and pumped it up to 15 psi, crack the bleed screw and then I do get coolant out of the hole, but still none when revved.

    I let it run long enough and the temp will creep to 3/4 and when I shut it off the upper rad hose boils.

    I've tried filling the rad hoses before starting as well.

    The only variable is that I had this same issue with the original head after replacing the head gasket. So I figured it was cracked and got another one which I did not have tested before install, but it was off a solid runner from a legit seller. However, at this time I do not have combustion gases in the expansion tank.

    I'm baffled guys, I work on BMW's all day, every day for a living, and I have never had this much difficulty with a cooling system!

    Anyone have any ideas on what I can check? Encouragement? Offers for a niceish 318is?

    Sorry for the lengthy post, just trying to make sure I didn't leave anything out.

    Thanks.

    #2
    when all else fails. say a cuss word and leave it over night. then come back and try again the next morning. always works for me

    yay for fatty air pockets

    Turbo M42 Build Thread :Here
    Ig:ryno_pzk
    I like the tuna here.
    Originally posted by lambo
    Buttchug. The official poster child of r3v.

    Comment


      #3
      Haha, it's been a few nights, a few dozen beers, and a dictionary of cuss words.

      Comment


        #4
        are both sides of the radiator warm to the touch?

        Turbo M42 Build Thread :Here
        Ig:ryno_pzk
        I like the tuna here.
        Originally posted by lambo
        Buttchug. The official poster child of r3v.

        Comment


          #5
          Originally posted by Dj Buttchug View Post
          are both sides of the radiator warm to the touch?
          Yeah it's warm. The upper hose gets pretty damn hot.

          Comment


            #6
            ive had issues with pockets of air in the actual block. Have you drained the block completely of coolant before filling?

            Turbo M42 Build Thread :Here
            Ig:ryno_pzk
            I like the tuna here.
            Originally posted by lambo
            Buttchug. The official poster child of r3v.

            Comment


              #7
              Originally posted by Dj Buttchug View Post
              ive had issues with pockets of air in the actual block. Have you drained the block completely of coolant before filling?
              Initially yes, but it's worth a try for sure.

              Comment


                #8
                17mm under the exhaust header...

                fwiw did you check for head warpage on the new head? sometimes removal can warp it if its not removed correctly. seen this a few times too. Im sure you know that tho. maybe slight warpage leading to hg fail somewhere...???

                Turbo M42 Build Thread :Here
                Ig:ryno_pzk
                I like the tuna here.
                Originally posted by lambo
                Buttchug. The official poster child of r3v.

                Comment


                  #9
                  I did check it with a straight bar, couldn't even see light under the bar.

                  I used a Victor Reinz HG the first time. Used a Goetze then second time and will never use a VR again. The Goteze was far superior just by looking and feeling it.

                  Comment


                    #10
                    did you use a feeler gauge to check under the straight edge. No more than .004 is allowed on the m42 head, which wont always show light between...

                    but yes. VR is terrible. I have invented new cuss words dealing with their head gaskets.

                    Turbo M42 Build Thread :Here
                    Ig:ryno_pzk
                    I like the tuna here.
                    Originally posted by lambo
                    Buttchug. The official poster child of r3v.

                    Comment


                      #11
                      Originally posted by Dj Buttchug View Post
                      did you use a feeler gauge to check under the straight edge. No more than .004 is allowed on the m42 head, which wont always show light between...


                      Interesting...well I'll give it some more attention tonight and see what's up. Had the chance to get a complete m50 swap for about $600 too...

                      Comment


                        #12
                        Update:



                        Bled it over and over with my pressure tester on while repeatedly stopping to top it off. Then ran it for 5 mins or so until both rad hoses warmed. Revved and opened screw while keeping topped off until no more bubbles. Closed it up and let it idle for 15-20. So far so good. Tomorrow I will get insurance and go do some laps around the neighborhood. Yay.
                        Last edited by Carter_22; 09-08-2011, 09:08 PM.

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