Gearbox dipstick nut spinning

[CloveHitch]

I want to check the oil level in a PRM 120 gearbox.

The white plastic nut retaining the dipstick is spinning and hence the dipstick does not come out.

Is it likely/possible that the nut has been ‘threaded’?

I have tried pulling tentatively with pliers. I wondered if anyone has any ideas, or had this problem, before I try pulling a bit more forcefully.

 

[RichardS]

I don't know your gearbox but may gearboxes have a threaded dipstick rather than the pull-type dipsticks on engines. Are you sure that you're not just supposed to be unscrewing the dipstick?

Richard

 

[Seajet]

Or a simple pull out maybe with a quarter turn first ?

Never heard of a threaded dipstick on an engine, though I've sailed with a few.

 

[Freebee]

if it is threaded and and you turned it the nut end would rise by one thread pitch per turn and possibly you might be able to see this,

 

[CloveHitch]

Thanks Richard. The manual says "Screw the dipstick fully down then remove it and read the oil level." I've tried unscrewing but the nut is simply spinning (hence my thought it might be stripped). I've also tried tugging.

I'll try SeaJet's suggestion of a quarter turn first, and other permutations.

Not sure what to try if these fail.

 

[Freebee]

A quick google shows it should be threaded.... so its possibly stripped I would apply a little leverage with a screwdriver under the head whilst turning it!

 

[VicS]

I want to check the oil level in a PRM 120 gearbox.

The white plastic nut retaining the dipstick is spinning and hence the dipstick does not come out.

Is it likely/possible that the nut has been ‘threaded’?

I have tried pulling tentatively with pliers. I wondered if anyone has any ideas, or had this problem, before I try pulling a bit more forcefully.

Not at all uncommon for gear boxes to have screwed in dipsticks

See your owners manual for the gear box.

If you have mislaid it you will find it here http://www.prm-newage.com/media/PRM Owners Handbook.pdf

The workshop manual is here http://www.prm-newage.com/media/File/PRM120.pdf

I'd suggest pulling gently while unscrewing

 

[CloveHitch]

Thanks FreeBee: if I can contort my old body sufficiently to get close enough, I'll try that and see if it diagnoses a threaded nut. Will try your leverage technique too.

 

[NorthUp]

Are you trying to remove the gearbox breather?
The dipstick is under a brass threaded hexagon headed cap on the starboard side, top of gearbox, see link..

http://www.prm-newage.com/media/File/PRM120.pdf

edit- missed Vic's post above

 

[Seajet]

If the dipstick really is threaded that would imply a dry sump, high performance engine as in racing cars, which seems unlikely - the gentle but constant pull seems the best bet.

 

[NorthUp]

If the dipstick really is threaded that would imply a dry sump, high performance engine as in racing cars, which seems unlikely - the gentle but constant pull seems the best bet.

No. Stick to photography!

 

[RichardS]

If the dipstick really is threaded that would imply a dry sump, high performance engine as in racing cars, which seems unlikely - the gentle but constant pull seems the best bet.

I've no idea what that means ..... but it's clear that the thread on either the dipstick or the gearbox casing are stripped. Let's hope that it's the dipstick so you can just buy another. Unscrew and pull up at the same time as others have said.

Richard

 

[Seajet]

Quite happy fiddling with engines ta, you stick to your crayons

 

[VicS]

Or a simple pull out maybe with a quarter turn first ?

Never heard of a threaded dipstick on an engine, though I've sailed with a few.

You have now !

 

[fisherman]

I'm confused because online info I can find indicates a brass dipstick with nut, to be unscrewed, as I would expect from my experience of PRM boxes. Is the breather plastic?

 

[john_morris_uk]

Quite happy fiddling with engines ta, you stick to your crayons

No need to be rude.

Lots of boat gearboxes have threaded ‘screw in’ dip sticks. Our current one does and I’ve seen loads of others on yachts and motorboats and workboats.

 

[RichardS]

No need to be rude.

True .... although I don't really see what that is any ruder than the "No. Stick to photography! " which started it.

Richard

 

[Seajet]

No matter, I've been reminded of threaded dipsticks - I remember wondering if the measurement was ' just resting, or fully screwed in ' - well it was nearly 50 years ago...

 

[RichardS]

No matter, I've been reminded of threaded dipsticks - I remember wondering if the measurement was ' just resting, or fully screwed in ' - well it was nearly 50 years ago...

And here we are, 50 years later, and one of the most common gearbox questions on here is still "just resting or fully screwed in". :encouragement:

Generally, the answer seems to be "just resting" but there are enough exceptions to prove the rule.

Richard

 

[Spyro]

or a simple pull out maybe with a quarter turn first ?

Never heard of a threaded dipstick on an engine, though i've sailed with a few.

it's a gearbox