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Throttle Body gasket question

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  • Throttle Body gasket question


    I'm in the middle of replacing my throttle body gaskets. I'm installing the e34 M5 paper gaskets. My question is do people order new rubber isolators as well when they do this job? or just add the paper gaskets and an rtv compound? Mine are showing age and are cracking.

    Last edited by RXPX; 04-08-2013, 11:33 AM.

  • #2
    You need both


    • #3
      That is correct you need to replace the rubber isolators along with paper gaskets.



      • #4
        Yes to replacing rubber isolator.. I just changed mine a couple weekends ago and noticed a difference in engine responsiveness - mine were aged and look to have never been replaced.
        One letter. One number. One legend ///M3.


        • #5
          I'm doing this job at the moment. TBs are now off the car and I'm about to start cleaning, parts ordering and re-assembly. I'd be really grateful for thoughts on the following:
          - Sealant; a previous tinkerer has used sealant between the gaskets and the TBs, but not between the gaskets and the head. My plan is to use the E34 M5 paper gaskets, but no sealant.
          - Fittings for brake booster and ICV vacuum hose. These can be simply pulled out of the TBs. What do people recommend to attach them more firmly ?
          - What else to do, while I am in there. I am certainly going to replace all the vacuum hoses - 2 from the ICV, 2 from the oil separator and one from the fuel pressure regulator. It's also a chance to clean up the head and the TBs. I am flirting with the ideal of a plenum repaint (it's an EVO2) but we'll see how I do for time. Anything else I should be doing ?

          I am looking forward to comparing the new rubber gaskets to the old ones.

          Intriguingly, I noticed 4 of the torx nuts that hold the TBs onto the head had little metal collars around the head studs. One of these came away with the TBs and the other 3 stayed in situ. Conceivable one of these could fall down the head ports on removal, so something to watch. I plan to hand crank the engine immediately after re-assembly but I'm pretty sure nothing disappeared.

          The good news was I got all the torx bolts / nuts off with no drama. spraying a few days earlier with WD40 seemed to help.


          • #6
            - Sealant: I've always used sealant on both sides of the gaskets. M5 paper gaskets do work.
            - Fittings: Clean both surfaces thoroughly and use JB Weld to reattach.
            - What else: I often clean the entire TB's in an ultrasonic bath using hot soapy water.
            - Metal Collars (dowels): These are an interference fit in the head, so they should not fall out. Use a tiny socket to tap it back into the head.
            Ron ///Man

            • '91 Gr-A Former CiBiEmme / Ravaglia - Sold
            • '90 M3 Faux EVOII Alpineweiss 36K Orig Owner - The Queen
            • '91 M3 Faux EVO III Brilliantrot Euro Driveline - The Rocket
            • '91 M3 Faux Gr-A Club Racer DM - The Alter EGO
            • '89 M3 M3T / ITR Club Racer
            • '94 Spec E36 - Eh....
            • '09 M3 - Tarmac Terrorist
            • '04 330Xi Sport 6 Speed - Snowmobile
            • '07 530 Xi - Highway Star


            • #7
              thanks Ron. Appreciate you taking the time to reply. I will tap that dowel back in.


              • #8
                Buy a few extra torx nuts for the rubber/plastic gaskets because chances are you'll round a couple.

                You'll also notice the seals in all of your needle bearings have deteriorated, so remove and replace those.

                Buy these double sealed needle bearings from McMaster Carr:

                You will need 4x of the 8mm and 3 of the 12mm - lubricate with light sewing machine oil.

                I used the Turner gasket kit with some Permatex gasket maker on both sides. If I had it to do again, I'd use the spray stuff to get a more even coat, but I still have no leaks.

                There are a few decent tips here:
                Alles Beste!

                B. Wheaton
                1989 E30 M3, Owner since June 2000
                2008 E61 535xiT - The DD and work horse


                Register your E30 M3!


                • #9
                  thanks Brandon. I managed to get all the torx nuts / bolts off but great tip on the needle bearings..... dismantling the TBs for cleaning is my next job.


                  • #10
                    So I finally completed this, car needs its road worthiness check (MOT) in the UK this week so couldn't do a long drive but the idle is now night and day better, and the engine much more responsive at low revs - I had obviously got used to the intermittent misfiring.
                    - didn't use sealant, but did use the M5 paper gaskets on the head side.
                    - did round off one of the bolts that hold the rubber mountings onto the TBs - but thankfully that happened when the TBs were off the car, so easily resolved.
                    - decided to use hylomar on the vacuum elbow fittings for the brake booster and the ICV hose
                    - noticed the nit that holds the plenum onto the lower mount was never there - so replaced that (M8).

                    overall a lot of hoses were in bad condition, and the missing ICV rubber mount and plenum bolt I'm sure led to much more vibration. overall well worth doing....