Results 1 to 6 of 6
  1. #1
    Join Date
    Dec 2019
    Location
    amersham
    Posts
    273

    Taper thread sealant

    Can anyone recommend a good taper thread sealant. I have a situation where the heater take off hose connection on my chevy 350 is leaking via the threads, i have used ptfe tape and its still leaking. In theory taper threads should be self sealing but i suspect the thread is slightly undersize hence the problem. A thread sealant that perhaps hardens would be okay.

  2. #2
    Join Date
    Aug 2004
    Location
    Christchurch, NZ
    Age
    60
    Posts
    2,522
    Just about any thread sealant should do, it's a low pressure system.

    Tapered threads do need thread sealant unless they are 'dry-seal' threads. This is the difference between NPT and NPTF threads - the latter is a dry-seal thread and should not need sealant BUT both the threads must be NPTF for this to work. The Chev heater connections are NPT.
    Cheers

    Myles D-W

  3. #3
    Join Date
    Dec 2007
    Location
    cheshire
    Posts
    1,437
    ARP thread sealer works for me, it's resistant to oil, petrol, water Inc antifreeze solution. It's like a paste that goes off but it stays like a firm paste without going rock hard. Memory thinks that they use it on Chevy bolts that thread into the water jacket.
    Lee
    .............never drive faster than your guardian angel.

    cobraclub.com/gallery/showgallery.php/cat/633 - this is the link to my build photo's you have to put w w w . h t t p : / / in front of it!!

  4. #4
    Join Date
    May 2004
    Location
    Cowbridge, United Kingdom
    Age
    63
    Posts
    10,397
    PTFE tape works in most situations.
    Kev Davies
    South Wales Area Rep. UKCC Membership Secretary
    DAX Mk4, 383 Chevy Stroker, Tremec. SOLD
    Contemporary CCX 3-4028, 445ci Big Block FORD FE,TKO 600, Old School IVA'd and SOLD
    Dax De Dion LS2 and T56 IVA'd June '17 SOLD
    1965 Ford Mustang 289 Convertible SOLD
    In build- Hawk 289 Sebring Awaiting IVA

  5. #5
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    43
    Posts
    4,951
    I was going to say the same thing - it's the thickest thread sealer I've used, too. I've used it on the oil temp, water temp and oil pressure fittings (all taper thread, NPT). There's also Loctite 542 and Loctite 577 - I've not used the 542 yet as the ARP stuff seems to do what I need, and I've not used 577 on an engine but have used it on all sorts of other water/air/etc fittings and IIRC it's a yellow goop which doesn't fully set, but doesn't contain PTFE (which the ARP stuff does).
    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  6. #6
    Join Date
    Dec 2019
    Location
    amersham
    Posts
    273
    Thanks for the replies.
    I think the problem is a cheap aftermarket part that i purchased where the gauge plane diameter of the thread is undersize, this affects the hand tight engagement and also prevents proper sealing when wrench tightened.
    Screwfix sell a thread sealer which i will give a try if that does not work then its a case of ordering a better manufactured part.
    Regards

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •