Mick Foster Posted August 24, 2021 Report Share Posted August 24, 2021 A very simple question. Can you use plumber's PTFE tape to seal the threads on a leaky engine sump plug? I just cannot seem to stop it dripping. I have tried a hex headed plug from Rimmers but it seems a bit sloppy in the thread and I worry that over tightening it will strip the threads. I have also tried a new square headed plug (traditional tapered thread type) but even with it really tight it still drips. It's not a big drip and is only a problem as it leaves a mess on the garage floor. If PTFE tape works then it will be an easy fix as I will be doing an oil change soon, I am just concerned that the tape is not oil resistant and will deteriorate leading to a bigger problem. BTW it's a Spitfire 1500. Many thanks. Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 24, 2021 Report Share Posted August 24, 2021 The plug has a tapered thread which should be self sealing. Is it possible that a parallel threaded plug has been fitted in error, or the thread in the sump boss is worn? Anyway, a little PTFE tape won't do any harm and may possibly stop the leak. Nigel Link to comment Share on other sites More sharing options...
Andy Moss Posted August 24, 2021 Report Share Posted August 24, 2021 Yea that’s fine. Link to comment Share on other sites More sharing options...
Mick Foster Posted August 24, 2021 Author Report Share Posted August 24, 2021 Thanks Nigel. I agree the thread is probably damaged but this must have happened before I bought the car in 1984. A new sump is probably the answer but it's a bit drastic for a minor niggle. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 24, 2021 Report Share Posted August 24, 2021 is used for hydraulics so a bit of sump oil should be fine are you sure its not a crack in the brazed in threaded insert list of ptfe compatibles Fluoramics Full Density PTFE Tape may be used with . . . Acids Air Alkalis Bottled Gases Chlorine Corrosive Chemicals Hydraulic Lines,<<<<<<<<<< Hydrocarbons Large Diameter Piping Natural Gas Oxygen Potable Water Propane Refrigerants Sewage Solvents Sprinkler Systems Steam Link to comment Share on other sites More sharing options...
Nigel Clark Posted August 24, 2021 Report Share Posted August 24, 2021 Pete is correct to mention the possibility that there could be a leak from the braze that holds the drain plug boss to the sump pan. I had a leak from that joint on a Spitfire, due to a hairline crack. Girl Link to comment Share on other sites More sharing options...
Mick Foster Posted August 24, 2021 Author Report Share Posted August 24, 2021 I think it is the thread but I will have a closer look and see if I can determine which it is. If it is the braze then of course no end of tape is going fix it and I will have to live with an oily patch on the floor. Link to comment Share on other sites More sharing options...
Peter Truman Posted August 24, 2021 Report Share Posted August 24, 2021 Re ptfe tape we recently had the direct mains pressure hot water service replaced and the plumber used a ptfe thread ratherthan a tape this winds around the root of the thread so it doesn't get cut by the sharp edge of the threads or turn out when tightened also easier to put on, but seals as effectively. It would be good also on oil and temperature sender threads. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 the old trick to source a leak is dry it and give the area a good puff of talc or similar the leak will show the trace through the dusting and with little pressure in the sump a clean and a bead of silicon around the collar will work for a long time if its got a leak Pete Link to comment Share on other sites More sharing options...
johny Posted August 25, 2021 Report Share Posted August 25, 2021 The other thing is that taper threads only seal when done up pretty tight. They basically rely on the threads being mashed together which is why the square drive can easily get damaged and its essential to use a tool that positively locates and gives plenty of torque. I use a thick jaw, good quality 12" adjustable and pull it up as much as I comfortably can. Link to comment Share on other sites More sharing options...
NonMember Posted August 25, 2021 Report Share Posted August 25, 2021 51 minutes ago, johny said: taper threads only seal when done up pretty tight Well... yes and no. It's not really any tighter than a copper washer needs, but certainly more than finger tight. They do, however, rely on both threads being in good condition and not pitted or distorted. Link to comment Share on other sites More sharing options...
68vitesse Posted August 25, 2021 Report Share Posted August 25, 2021 1 hour ago, johny said: The other thing is that taper threads only seal when done up pretty tight. The sump plug thread is ⅜ Dryseal, according to my WSM, this is NPTF which was designed to seal dry, F stands for fuel, were as NPT which has same diameter and thread pitch in some sizes will not. I made this mistake when installing a drain plug in my diff. a few turns of Loctite55 sorted it out. Regards Paul Link to comment Share on other sites More sharing options...
ahebron Posted August 25, 2021 Report Share Posted August 25, 2021 I got told off for mentioning I used ptfe tape on another Triumph forum. Doesnt stop me using it, I always use it on aluminium washers on sump plugs on bikes and cars. I just keep it near the head of the plug so it seals at the outside of the hole only. Loctite do a gas/liquid seal product for threads but I have never used it on a sumpplug Adrian Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 loctite do a hydraulic sealer( we used it on production) but its a pig to undo so great on hyd brake pipes but on a sump plug just any simple sealer will work Pete Link to comment Share on other sites More sharing options...
johny Posted August 25, 2021 Report Share Posted August 25, 2021 5 hours ago, NonMember said: Well... yes and no. It's not really any tighter than a copper washer needs, but certainly more than finger tight. They do, however, rely on both threads being in good condition and not pitted or distorted. As a guide the manual says apply 10kg to the end of a 12" adjustable.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 thats only 22lbft or just a gentle hand tight with a 12" wrench no gorilla hands here Pete Link to comment Share on other sites More sharing options...
johny Posted August 25, 2021 Report Share Posted August 25, 2021 Easy, pick up 10L of water and apply the same effort to the end of the spanner, or get a torque wrench of course.... Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 well to save getting wet !!!.........as an indication a one handed hard pull on a 12" spanner will exceed 60lbft quite easilly so at 22 is a nip not a graunch Pete Link to comment Share on other sites More sharing options...
johny Posted August 25, 2021 Report Share Posted August 25, 2021 Trouble is under the car, laying on your back I find its not so easy to get the normal arm effort so wonder if in some cases people are not giving the drain plugs enough... Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 under the car i find nothing is easy these days like what am i doing down here for a start Link to comment Share on other sites More sharing options...
NonMember Posted August 25, 2021 Report Share Posted August 25, 2021 1 hour ago, johny said: in some cases people are not giving the drain plugs enough... ... or in other cases they're giving them too much and cracking the boss. Actually quite easy with taper threads. Link to comment Share on other sites More sharing options...
johny Posted August 25, 2021 Report Share Posted August 25, 2021 Must be gorillas to do that under a car plus have a really good tool as it normally slips and/or rounds off soft plug head long before splitting bosses! Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 25, 2021 Report Share Posted August 25, 2021 there is nothing on a triumph that needs a gorilla and torque wrench figures are there to aid control of fixings when you only have a gorilla handy most spanners are of the length that gives you control with a steady one handed pull using the same effort over multiple fixings and you can be surprisingly accurate Pete Link to comment Share on other sites More sharing options...
PeteH Posted August 25, 2021 Report Share Posted August 25, 2021 I’ve never really been afraid to use PTFE when needed on any sort of thread except where electrical continuity is necessary. Back in the day we used “boss” white and hemp on hot water and low pressure steam too. Link to comment Share on other sites More sharing options...
ahebron Posted August 25, 2021 Report Share Posted August 25, 2021 Could investigate fitting one of these to our small chassis Triumphs. I have fitted them to three of my last vehicles, 300 TDI Discovery. L322 RR TD6 and VW Amarok. https://www.fumotousa.com/ (added after original post) or this brand https://www.ezoil.com.au/ Link to comment Share on other sites More sharing options...
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