Oil leak from mystery bolt

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juzza
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Oil leak from mystery bolt

Post by juzza »

Hi folks

Apologies if this has already been posted....

I have an oil leak from a mystery bolt, which appears to be on the lower timing case (red arrowed in two attached pics). I reckon it's probably a simple gasket change but I don't want to crack the bolt without knowing what its for, especially if someone's done this one before. Any tips?
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GRNSHRK
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Re: Oil leak from mystery bolt

Post by GRNSHRK »

Well, it's not that simple :-?

It probably is the lower timing cover gasket that's leaking, but in order to remove the cover, you have to remove the big honkin' 36 mm nut on the end of the crank shaft :-({|=

You might want to just keep it clean for now, until you are ready to do some other service, like the belts as well :-"
:mrgreen:
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Ralph in Socal
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Re: Oil leak from mystery bolt

Post by Ralph in Socal »

That mystery bolt is actually the cover for the timing chain tensioner spring

It's holding a spring and piston that pushes against the tensioner rail. Remove the bolt (nut?, cover??) and the spring will fly if you're not careful and ready to catch it

There is an Aluminum crush washer in place to reduce leaks. Simply replacing the washer may help fix your leak. In extreme cases the sealing surface needs to be restored (sanded flat) to effectively seal again.

The piston may need to be re-primed after taking it apart. Bently has the easy to follow procedure

Ralph
Last edited by Ralph in Socal on Mon Aug 15, 2022 8:11 pm, edited 1 time in total.
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GRNSHRK
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Re: Oil leak from mystery bolt

Post by GRNSHRK »

Doh #-o

I didn't look at the arrow in the second screen capture :roll:

Yes, plus one, timing chain tensioner :-"
:mrgreen:
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Jubilados
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Re: Oil leak from mystery bolt

Post by Jubilados »

Like said above, it’s probably not actually leaking from there.
You might get lucky and it is . . . but highly unlikely.
marc79euro645
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Re: Oil leak from mystery bolt

Post by marc79euro645 »

I've had the same leak before. It may be the valve cover gasket, or upper timing cover. The motor lays over at an angle, and often the leaks shows up on the timing tensioner, but is actually from above somewhere.
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86_6series
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Re: Oil leak from mystery bolt

Post by 86_6series »

+1 on the oil leak. I also thought it was the crush washer on the tensioner bolt.
Wound up being a loose bolt on the timing cover. The fan blowing caused the oil to accumulate
on the tip of the tensioner housing. After installing 3 washers, I finally checked and found the loose bolt.

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juzza
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Re: Oil leak from mystery bolt

Post by juzza »

Many thanks folks, won't be touching that any time soon!!!
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Jackie&Gracie
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Re: Oil leak from mystery bolt

Post by Jackie&Gracie »

Just read this thread.

I have the same drop of oil on the same tensioner/spring/piston retainer bolt. Will look at the timing chain cover bolts first, then maybe the valve cover bolts for good measure. General wipe up all around. Keep an eye on things.

Thanks guys, many thanks -
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