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Discussion Starter · #1 ·
Hi there .
A long time lerker (since 2014) I'd like to thank daytreper and peva for the wealth they contributed to this form .
I have 2001 Chrysler intrepid 2.7 with 170 thousand KLM . The car is great , I've been using synthetic oil for 9 years , the engine still purr like a kitten , no water pump issues , but it's been leaking oil from the valve cover gaskets .
Today , I removed the covers (real pain) and put the new gaskets . The engine is Uber clean+chain guides plastic layers are still thick , but I noticed the tensioner wasn't fully extended , and the timing chain was a little loose on the chain side that comes from the water pump (the chain side of the tensioner was tight) .
So , I turned the crankshaft a full turn and the tensioner extend to the normal level (about an inch , there was half of an inch of carbon build up on the tensioner), and the chain slack was gone and it was tight again .
Two years ago , I accidentally turned the engine counterclockwise (stupid me) , that made me think , maybe it caused the tensioner to push inward to itself (?) . Do you think ?
Should I worry ?
Thanks again
 

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When you rotated the engine CCW, it could have caused the tensioner to have been compressed into its latched shortened condition. The important thing is that you have proven (by its extension) that your tensioner is in its released (extended) condition - not latched.

(There is a line that will be revealed on the tensioner if the chain is worn to the point of needing to be replaced.)

The tensioner has a spring inside it that tends to extend it with a relatively weak force. That force tends to tighten the chain, but is not enough to keep slack out of the chain, but is important in the process of getting the tensioner pumped up to develop full chain tension once the engine is running.

The real chain tension is achieved by hydraulic pressure of engine oil inside the tensioner. Contrary to popular belief, the full tensioning force is not created by pressure from the oil pump.

The tensioner works just like a valve lifter (lash adjuster) to develop that full tensioning force. The base end of the tensioner is a cylinder, and the chain end is a piston assembled onto the base end. The base end of the tensioner has a hole and a check valve in it, and is bathed in unpressurized oil. When the engine is running, the chain experiences pulses of force generated by the cogging action of the cams. The pulsing forces are transmitted by the chain to the tensioner, which causes oil to fill the tensioner thru the check valve in a pumping action as it rapidly opens and closes in sync with the cogging pulses.

So that's how the tensioner develops its full chain tensioning force.

When the engine is shut off, depending on final resting rotational position of the cams and the resulting net rotational force on the cam lobes created by the valve springs, the chain may be pressing against the tensioner, and over time (minutes? hours?), that force of the chain pressing against the tensioner causes oil to leak out of the tensioner, so the tensioner partially collapses. That is why you found slack in the chain. As long as your tensioner was not latched into its fully compressed and latched state (which yours is not), when the engine is started, the weak spring inside the tensioner applying the small force to extend the tensioner, combined with the cogging pulses from the cams rotating, causes the tensioner to fill with uncompressible oil and pump itself back up, and, voilà! - you're back to a fully tensioned chain again.
 

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Discussion Starter · #3 ·
Thanks Peva for the quick response .
I've been worrying about it all night , I remember (two years ago) I removed the timing cover to check on the water pump even though no water leak , it was good (the old style) and I remembered how the engine turned CCW when removing the crankshaft .

Yesterday , the first thing I checked when I removed the valve cover was to look at the tensioner and see if I see the mark , but instead , I saw the tensioner extended about half an inch with a very thin coating of carbon covering it . Upon noticing the little slack and remembering the CCW turn , I turned it clock wise and then the tensioner extended another half of an inch . A full inch , half of it shiney , the other half coated by brownish carbon (which I cleaned) , I'm curious to see the tensioner again , but , noway I'm going to remove the valve cover again , I have cuts allover my hands + lower back hurts (lol).

Well , thanks again .
 
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