C25xe V6 spark plugs. What torque?

[GP123]

Hi all.

I got bosch spark plugs there for my V6 and it says 28 nm of torque on the side of the box. Does this sound right?

Thanks.

[Robsey]

Yes this sounds correct.
28 nm is approx 21 ft lbs.

It is understood that the "safe range" for fitting a spark plug is 15 to 35 ft lbs.
Beyond these values it is reported that damage may occur.

So again, the simple answer is...

28nm or 21 ft lbs is perfectly correct.

[GP123]

Thanks Robsey. Legend as always mate

[Robsey]

Thanks Robsey. Legend as always mate

Ssshhhhhhh!!
Don't tell everyone - ha ha.
My pleasure, always keen to help.


I have always fitted at 18 ft lbs for my 13S, C18NZ and C20NE engines.

But the safe range values quoted are taken from my recent TSBs thread, where various types of spark plug failures are listed.

[James McGrath]

I must admit, I've never fitted spark plugs to a standard torque value before.
I just tighten them until they feel snug.

Maybe I'll do it properly next time.
Good excuse to get the torque wrench out!

[GP123]

Yeah so done the cam covers on the v6 last saturday morning and done new spark plugs, coilpack and leads also.
First start sounded smooth but then i heard a tick come in and progressively got louder like a constant drum noise.

So put my ear over the front cam cover and narrowed it downto the first spark plug. So i assumed it had loosened and would you believe it i was right, set the torque wrench to 28nm of torque and near done a half turn on it. Done the 2nd and 3rd and they just needed a tiny turn to click.

Only thing is i want peace of mind for the back spark plugs, the only thing is now i have to get the intake manifold back off.... ah well. Its worth it as it runs better etc with the breathers cleaned also! Thanks to James McGrath for his thread as it was a big help. I never even would have checked the breathers!

[Robsey]

As with anything I suppose.

Fit to torque,
Let it run and settle,
Then re-check the torques again.

Being an old duffer, I work in pounds / feet.
I think the main thing is, not to swing on the socket / torque wrench like a heavy handed baboon.
As James pointed out, just tighten to what "feels" right.

Amazingly - just checked the V6 2.5 litre engine in the Omega-B Haynes manual and it quotes the same torques that I did...
18 lb/ft or 25Nm