mysterious oil loss....

[dmr]

Is that a parallel or tapered thread?

Torque should be a bit more than hand tight but Google should help.

 

Try with no tape or sealant, but if that leaks then use a bit of tape but this is not ideal. You really don't want to let anything get into the oil passage so if you use tape it could just leave a bit behind next time you take the sender out, then get dislodged when you put the sender back in, but we are talking very small risks here.

 

............Dave

[Flyboy]

Its arrived. Any idea how i could find the torque setting? Also should i use a thread sealant or maybe a teflon tape?

It looks like it has a tapered thread as it should. With a single wire sender you should not use any sealant or thread tape because it needs an earth return. A tapered thread does not need sealant.

 

A torque setting for 1/8" BSP or NPT thread would be 12 lbs.ft. ( 17 Nm )

Edited January 10, 2017 by Flyboy

[mross]

I think one or two wraps of thread tape would help seal it without completely insulating it. Any info on the box it came in? Such as thread size?

Edited January 10, 2017 by mross

[WotEver]

Unless it's the angle of the camera that thread definitely looks tapered to me.

[bizzard]

A tapered threaded one shouldn't need any tape or sealant, risky with the -neg contact as someone mentioned. I must have renewed hundreds of them on vehicle engines in the past and can't remember any ever leaking from the tapered thread always the insulator body.

[Flyboy]

I think one or two wraps of thread tape would help seal it without completely insulating it. Any info on the box it came in? Such as thread size?

No, a tapered thread doesn't need any help to seal it. Why introduce an unnecessary medium that is going to possibly cause an unreliable electrical connection?

[mross]

Because NPT threads require a sealant. There is a leakage path at the root of the threads. does not matter how tight. but it might be a BSP.

[bizzard]

NPT thread form is self sealing. Ok in a pipe coupling where the male part might stretch the female part a touch might need a bit of sealant tape but the cylinder block of an engine is hardly going to stretch with the thread of a wee pressure switch screwed into it, no matter how much its tightened.

[wobbly ollie]

Oops apologies.... bit of a can of worms unintentionally opened...? How about i go without any sealant or tape. Tighten to correct torque (thanks Flyboy) and see what happens...? Be interested to see whats on the one thats coming out. Also be good to know whether leakage is coming through the unit or around eg. Through the thread. Not sure whether that will be evident though and may remain a mystery.

[RD1]

With reference to tapered threads, on my 4x4 gearbox and diffs, ( Nissan Terrano lol) I always add some thread sealant, I used to use "Calor tite" or "Gas tite" as it never fully hardens, no plug ever leaked, but the advantage was, it sealed the thread, and no water and salt can get in to corrode the threads and sieze the plug.

Several years on, and the plugs come out with a standard 1/2" ratchet set, some meths to clean up the threads after removal, sorted.

 

Calor tite is not available now, it is frowned upon to rely on it on gas joints, this has been a swinging door, to seal or not to seal for a number of years according to various BSS inspectors but there is a red hematite type equivilent, that does a similar job on threaded plugs on my vehicle. For tapered threads, I apply the sealant to the threads in the last third of the thread so none should get into the gearbox or diff.

 

I can see the point about ptfe blocking oilways, if used on the oil pressure switch, since this is after the oil pump, the next stop for the oil are the big ends, bearings or rockers etc.

[Flyboy]

With reference to tapered threads, on my 4x4 gearbox and diffs, ( Nissan Terrano lol) I always add some thread sealant, I used to use "Calor tite" or "Gas tite" as it never fully hardens, no plug ever leaked, but the advantage was, it sealed the thread, and no water and salt can get in to corrode the threads and sieze the plug.

Several years on, and the plugs come out with a standard 1/2" ratchet set, some meths to clean up the threads after removal, sorted.

 

Calor tite is not available now, it is frowned upon to rely on it on gas joints, this has been a swinging door, to seal or not to seal for a number of years according to various BSS inspectors but there is a red hematite type equivilent, that does a similar job on threaded plugs on my vehicle. For tapered threads, I apply the sealant to the threads in the last third of the thread so none should get into the gearbox or diff.

 

I can see the point about ptfe blocking oilways, if used on the oil pressure switch, since this is after the oil pump, the next stop for the oil are the big ends, bearings or rockers etc.

Yes but your diff. didn't need good electrical contact like the op's pressure switch.

[puppy999]

Has the op sorted his oil leak ?? I and I would think that everyone else is interested to know ???

[wobbly ollie]

Apologies for not keeping you updated. I went to the marina to fit the new switch last Saturday. It was certainly a tight fit which being a tapered thread i kinda expected. However i was just over 2 thirds in and i was concerned how tight it was getting particularly as the one i removed was screwed in all the way home tight home up against the block. So with about 4mm to go i decided to stop and return once I've checked the torque setting. Better safe than sorry and last thing i wanted to do was over tighten or worse still strip the thread or gawd forbid.....crack the block.

[WotEver]

If it's a taper fit then it shouldn't go all the way in. The fact that the old one did is probably why it was leaking.

[wobbly ollie]

Thats a very good point...

[wobbly ollie]

Thats a very good point...

[Lamby]

Hi, I hope your leak is resolved with the pressure switch, however if not i had an oil leak which took an age to locate, it was a crack/ hole in the sump, I finally discovered it using a £2 mirror with a led light on it. have no idea how it could have happened, but i thought i would mention it. good luck

[wobbly ollie]

Okay folks it looks like its all sorted!. New pressure switch fitted and unlike the one it replaced it is not screwed all the way up tight to the block. In fact there is still around 4mm of thread showing? Strange that...Anyway its as tight as i dare go. Ran the engine for 20 mins today and so far all good. Thanks once again to all contributers.

[WotEver]

Glad it's sorted

 

As I said earlier in the thread (sorry), it's not unusual at all - a tapered thread should tighten up way before it's 'seated'.