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Sudden LOUD noise coming from engine top.

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  • Sudden LOUD noise coming from engine top.

    Car had been running fine, after startup I drove 1 mile and suddenly heard a very loud noise.

    -Metal banging sound seeming to come from front top end of engine.
    -Moves with engine speed I think
    -Seems like more than one noise is being created, one louder than the other, maybe 400BPM at idle
    -Banging is loud enough to hear inside over full stereo

    I shut it off right away, then had to start it to get off the street, engine seems to idle and respond fine for the very short period I drove to park it. The noise is so loud and scary to my ears I only ran it a few seconds with the hood up trying to source the noise.

    Maintenance history:

    Valves have about 15k since last adjustment, they were perhaps becoming noisier but nothing to note
    Just sent oil in and no bearing material at all on the report
    Tensioner is e36 with 40k or so on it
    This happened after driving in the hot CA valley for the first time but never has the coolant or oil gauges gone past half

    I am on a trip and stuck near Fresno, CA. Do not know any mechanics here. I assume I should not drive it?

  • #2
    im not an s14 guru like most people here but i can assure you, noises are not good i think you might have kicked a shim out of posicion and this will cause noises like that and also will screw up your cams. but honestly Best of luck and DONT drive it

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    • #3
      I would not drive it - you're either looking at trying to figure it out yourself, or have it towed to a mechanic or home.

      Once you have the tools: First things first - pull the valve cover and take a look for an ejected shim or anything else out of the ordinary. Try rotating the engine by hand with a big socket on the crank pulley - any resistance? Next I'd drain the oil filter through a filter (I use the kind auto body shops use to filter paint when mixing it) and then cut open the oil filter and look for bearing material in both places.
      sigpic
      Track Car Build | COM Sports Car Club

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      • #4
        I have a video upload of the sound now. Thanks for the suggestions.

        http://www.youtube.com/watch?v=3BlPyBKZsFk&feature=plcp

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        • #5
          Sounds just like mine! See here: http://www.s14.net/forums/showthread...d-head-rebuild

          Easy fix...

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          • #6
            So yours was exhaust studs that came out? My car did have loose exhaust studs, and several whose heads had snapped off.

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            • #7
              Originally posted by i see View Post
              So yours was exhaust studs that came out? My car did have loose exhaust studs, and several whose heads had snapped off.
              I would say this is your problem and by your video it sounds like it as well. If your engine/exhaust is cold put your hand in and see if the manifold moves.
              sigpic

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              • #8
                I went back out to where I left it and got underneath. It seems as though cylinder #1 exhaust header is held on by one loose (finger jiggle) stud. The gasket has fallen and rotated out. I was able to get a wire in the other stud holes about 1" deep in one and shallower in the other two.

                Does this look like enough evidence to be pretty certain of where the noise is coming from. I assume I can drive it home 200 miles like this as only exhaust is leaking and nothing is really being further damaged?

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                • #9
                  Make sure there's nothin that can catch on fire. I know someone that turned their lemons car into a charcoal briquette that way...
                  sigpic
                  Track Car Build | COM Sports Car Club

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                  • #10
                    i would Tow it safe insurance
                    91 M3 AW 2.5 CR Dogleg
                    88 M3 AW Track Car s54
                    95 525 Touring M52 Turbo
                    04 Toyota Tundra






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                    • #11
                      Original studs are M6 x 35mm. I suggest getting three M6x25 temporary bolts. Fit the gasket back into position, fasten the flange and drive home. Do not drive for long like that. There's oil on the motor and it could indeed catch fire.


                      [email protected]

                      1969 2002 racecar
                      1989 M3 racecar
                      e39 Touring

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                      • #12
                        Originally posted by LeeVuong View Post
                        Original studs are M6 x 35mm. I suggest getting three M6x25 temporary bolts. Fit the gasket back into position, fasten the flange and drive home. Do not drive for long like that. There's oil on the motor and it could indeed catch fire.
                        Perfect advice, I got the gasket back in place and 3 new M6x25 bolts holding the manifold on. There is only a small amount of exhaust leaking, I made it home 200 miles easily.

                        For reference, the sound seemed to come from the top of the head. Now I can hear that it was not metal hitting but exhaust. The tick-bang sound is closest to a loud twin motorcycle. The beat was also rpm/4 which makes sense.

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                        • #13
                          Attaboy. Glad it worked. ;-)


                          [email protected]

                          1969 2002 racecar
                          1989 M3 racecar
                          e39 Touring

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                          • #14
                            This is a very common problem. I check the nut/stud tightness at every oil change.
                            There'll be Spandex jackets one for everyone ...

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                            • #15
                              Glad to see it was an easy fix......
                              sigpic

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