Lost Timing Chain Tensioner Piston --Possibly fell into engine?

[lebowski9]

Hi,

2001 X5. 4.4 --Today I was re-replacing the exterior timing chain tensioner because I forgot the crush washer the first time I installed it. (the one that screws into right side of engine).

In case their are any doubts, this is the part no. I am referring to: 11317531813

Well, it was now fully extended and required some force to get the cap's threads to seat. I almost had it but lost my grip at the last second and the tensioner went flying!

So far I have found the cap, crush, washer, and main body + spring of the tensioner. However the end plunger (the smaller part) is nowhere to be found.

Is it possible for this piece to have fallen inside the engine or does the design prevent that?

No good deed goes unpunished...

[andrewwynn]

The tensioner arm is immediately inside the hole. Even without the outer part of the tensioner I don't think you could get it to fall in. Were it possible you can get through the oil fill cap

I could see the plunger getting left behind in the hole but you'd have to try on purpose to force it past the arm to get it to fall in

[lebowski9]

Originally Posted by andrewwynn

The tensioner arm is immediately inside the hole. Even without the outer part of the tensioner I don't think you could get it to fall in. Were it possible you can get through the oil fill cap

I could see the plunger getting left behind in the hole but you'd have to try on purpose to force it past the arm to get it to fall in

Thanks for the good news, Andrew. Tomorrow I will spend some quality time with the borescope looking underneath the engine bay.

[andrewwynn]

If you are doing big overhaul take off the stiffening plate you'll likely find several tools/bolts/nuts. I found my alternator nut.


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[lebowski9]

I've already got it off! I think it may have fallen on top of the triangular corner bracket which attaches to the tubular sub frame on the right side. this engine bay is like a black hole....

[andrewwynn]

I've lost two oil fill caps and a washer spray cap down there


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[lebowski9]

Success! I found it using the borescope, laying on a bracket aft of the ac compressor.

One last question, is there a simple way to disable the engine from starting so that I can allow the tensioner to pump up and avoid the scary noise?

On the old cars, you could just pull the coil wire and it would crank and crank until pressure built, is there an equivalent here without breaking out a laptop?

[andrewwynn]

Pull the fuel pump from fuse and poke the valve on the fuel rail

Or jump power to the starter solinoid. In the old days a screwdriver across the terminals.

I didn't bother on either of the M62 after replacing chain guides. The tensioner has a spring to preload and should be good enough for 0-100rpm before the engine starts.

[oldskewel]

At least on my 2001 3.0i ... if you pull the DME relay (light blue cube in the electronics box in the aft starboard corner of the engine bay), that will kill both the injectors and the coils.