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beware of the nylon/plastic drain plug gasket/seal

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  • beware of the nylon/plastic drain plug gasket/seal

    This is an increasing problem im seeing and for the most part it's the fast change lube places that are using these faulty oil drain plug gasket/seals,

    These flat rings are generally white but can be black and other colors as well,
    they are total crap and should never be considered for this application - you tighten your drain plug and then the engine see's heat and then over the next few weeks and months the nylon conforms and the drain plug loses tension and can get so bad it literally vibrates out,
    if reused and reused the gasket will actually get thinner and thinner and can crack and totally open up.

    Iv just had two honda's come in with these damn things and there was barely any tension on the drain plug, Iv also seen $5,000 dollar engines go up in smoke because of them - I thought people would catch on but the problem is getting way worse.

    The good materials are; aluminum - copper - and red or black fiber washers are fine,
    Do NOT use single piece injection molded nylon or any kind of single piece plastic looking drain plug gasket, they should be outlawed.

    drainplugs with a cut-out for an o-ring are great if you can find them.

    beware of the low budget oil drain places --- the 7 cent plastic washer they use could cost you allot of money....
    The idiots that design these things and use these material have no clue about the values of high unit pressure under heat...

  • #2
    Intresting, I just replaced the drain plugs in an outboard motor with those nylon ones. Mind you it was in the gearbox (2 stroke, so only the lower gearbox had oil) and is underwater. I guess i'll tell the owner next time I see him that nylon drain plugs might be a bad idea. (the origional where rubber, but needed an impact gun to get out! Flathead screws suck, new ones are allen key)
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


    • #3
      Black moons I would not worry the customer on that particular application, if this unit is submerged all the time it most likely does not see much heat, it's both the combo of heat and pressure that allows the plastic material to "let go" and relax, Iv seen an automotive drain plug so bad it looked as if the material was trying to "drip" it's way out,

      They do generally seal well because they conform so easy, its the combo of the material and heat so you should be good - still - keep it in mind and when you go to loosen them the next time take note on how much resistance their is, even if it runs totally cool it will conform and be more relaxed.


      • #4
        On the other hand, Black_Moons, don't make a habit of using nylon under water - it absorbs water and swells (about 6%, IIRC).
        A lot of folk have been caught by this, using nylon-based plastics as rudder bearings, etc. The rudder becomes very stiff, so they slip the boat to find out why, the nylon dries out and the rudder is perfectly free again! So the boat goes back in the water, the nylon swells, the rudder goes stiff again...


        • #5
          This must be a new form of plastic washer, as GM has used these for decades with no problems.
          The only problem i have seen is after a number of years that will tend to get squashed and grooved, but i have always just slipped on a new one if i found that.


          • #6
            This has been going on for a couple decades now - the scary thing is that they are actually becoming the norm.
            The next time I have one that has severely heat deformed I will take a picture of it and dig up this post.

            this is not an area to cut corners, one should be able to put ample torque on their drain plug and have it stay that way, getting "squashed" is definitely an indicator of the material relaxing, if it takes years to do so it's far better than the cheezy ones that iv been experiencing - and they are not OE on the honda's iv been working on, they use an aluminum washer from the factory and massive drain plug threads that you can pour the coals to when tightening.

            It does not surprise me GM's been using plastic.


            • #7
              GM has indeed been using a plastic washer on oil drain plugs since at least 1988. I changed the oil in my 88 Chevy pickup for 19 years using the same white washer... with no ill effects. I must have been doing something wrong.


              • #8
                HA, Oil change places...
                I once saw that they use a torque wrench to tighten the drain plugs.
                I think, Yeah, good idea in theory.
                Then the same guy uses the torque wrench to break loose the rear diff plug
                and he uses a CHEETER BAR on the torque wrench. Then it slips and drops
                on the floor. Hmmm. That torque wrench they use for drain plugs has got to
                be damaged to shlt. Oh well. Maybe hamburger technician would be a better
                career for this bloke.



                • #9
                  Did not say they are the same as the ones I see literally melting off of drainplugs, and in fact if you do take the time to read my post you will run across the sentence;

                  "if it takes years to do so it's far better than the cheezy ones that iv been experiencing"

                  The fact of the matter remains - there's no comparison to aluminum or copper, or the drainplugs that have a built in rubber O-ring but yet bottom out on steel...

                  so please don't take offense - the only thing you really did wrong is buy a chevy in the first place


                  • #10
                    Hmmm??? Don't know that I've ever changed the drain plug washer on any vehicle I've owned, never had any leakage problems.

                    O-rings are another matter, the drain plugs on my Harley's have an O-ring on them that gets torn up a bit, gets changed every 3-4 times the plug is out.

                    Never take my stuff back to the dealer, let alone one of the quickie change places.


                    • #11
                      We probably shouldn't get into harleys either,, I mean - lets face it - oil holding capabilities really has never been one of their strong points,
                      but if properly designed and if it's sealing against a smooth surface the O-ring drain plug is superior to all - it's also the most labor extensive to build because of the extra machining that the plug has to go through --- tolerance of calculated "squish" is also critical and if they are not done correctly will compress and bulge the o-ring too much and then severe it at the edges and tear it up... Iv seen this many times - also seen the good ones go a half million and still be like new and pliable...

                      Your wise not to trust either (dealers or fast lubes) - I don't even do oil changes - I just keep my eyes open when under a car - and when I see a piece of crap white drain plug washer bulging out on one side or cracked at the outer parameters and remove it and it's cracked 90 percent through then I feel I have to do something about it for my customer,
                      I also feel it my obligation to enlighten others about the subject because were talking an entire engine here folks...

                      If your one of the people that like them then good for u - but don't expect me to also - iv formed an opinion along time ago and it's based on observations and facts - and also saving about 5 engines for people over the years.
                      Last edited by A.K. Boomer; 10-16-2012, 11:33 AM.


                      • #12
                        No offense taken. I was unaware that there was another truck brand.

                        I think I got my money's worth for 19 years... and they made a damm fine drain plug washer to boot.


                        • #13
                          Originally posted by A.K. Boomer View Post
                          We probably shouldn't get into harleys either,, I mean - lets face it - oil holding capabilities really has never been one of their strong points,
                          Just FYI, the Twin Cam models built since 1999 are very oil tight, if you find a leak there is actually something wrong. I've owned 3 from 2001-up, never had a drop of oil from any
                          of them. Besides, we're talking drain plugs, which Harley never had a problem with, if was the rest of the joints that had issues. 'Course, anyone that designs an engine/gear box case split vertically is just asking for a leak, kinda like making a shower stall out of individual tiles.....DUH, it's GONNA leak sooner or later.


                          • #14
                            U guys are good sports - uh oh GarageMark - now your going to get the ford guys in a defense mode -

                            Hmm - your initials are even GM :-)

                            as far as vertical cases there's nothing wrong with them if you use the right sealant - a good quality firm bodied silicone will be a permanent seal - If the cases are machined properly,
                            Older volkswagon - Porsche - subaru just to name a few in the automotive industry

                            permatex grey is really good stuff for this application - and it doesn't stand out like a sore thumb when used on aluminum cases and such - far better than that flimsy florescent orange stuff that screams out at you "repaired by Jeb"

                            Honda makes it's own brand of grey and it's extra firm but will remain pliable for the long haul.

                            brake clean both surfaces and then put an extremely thin layer on both, then zip it up and make sure you see the tell tale sign of protrusion around the entire parameter...


                            • #15
                              The good sealant is called HondaBond or YammaBond.
                              It is actually made by Three Bond TB1104.