Timing Chain Seems Slack? Is that normal?

appatula · 08-08-2009, 09:13 AM

Yesterday I popped my valve cover off of the M103 in order to access the coolant temp sensor (for the high speed aux fan relay). The three prong guy. I did some poking around and everything looked super clean as usual. I did notice that my timing chain was, well...loose. From the front of the car facing the engine bay I looked over the timing chain cover and noticed that I could wiggle the chain on the RIGHT side and it was slack partway up the cog. The left side, (the side where that huge hex bolt is to access the timing chain tensioner) seemed tight with no play. Is this normal?

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ps2cho · 08-08-2009, 11:06 AM

From what I understand, if it is loose you should be able to hear it. Is it noisey?

appatula · 08-08-2009, 11:26 AM

Ehh, I've never heard what a noisy timing chain sounds like but there is no audible clacking or rattling from what I can make out at idle.

I just assumed that it should be tight enough so that a finger poking at it could not wiggle it back and forth, and even a bit of side to side play on the cog. I'll try to post pics later today as it is hard to pinpoint exactly with words. I'm just wondering if my tensioner is failing, I know the car has much over 200K and most likely has never had any internal work done to it.

I also can admit that from the seat of pants feel the power falls to almost nothing past 5K RPMs. I remember it being able to pull much more past that all the way to the red territory when I first got it.

appatula · 08-08-2009, 11:45 AM

Thanks to your picture I can clear everything up!

The chain part with the black housing over it on right side of this picture is where mine seems pretty slack. I stuck my finger down in there as the cover was still on but it did seem loose? Could make some sense as the tensioner is on the other side?

epowers777 · 08-09-2009, 07:43 AM

Theres probably slack from your cam cause the valve springs. turn the engine with a ratchet over a couple times. feel chain again should be tight. If you can here the chain slapping around worry. Also turn engine inspect chain for any wearing marks. chains also stretch. Do a google search might help!!

08-08-2009, 11:06 AM	#2
ps2cho MBWorld Fanatic! Join Date: Apr 2007 Location: SoCal Posts: 1,391 Drives: 1988 300TE, 1987 260E	From what I understand, if it is loose you should be able to hear it. Is it noisey? __________________ 1988 Pearl Grey Metallic Mercedes 300TE - 98k miles 1987 Black Mercedes 260E - 86k miles

08-08-2009, 11:26 AM	#3
appatula Super Member Join Date: Feb 2007 Location: Connecticut, New Haven Posts: 755 Drives: 1986 300E	Ehh, I've never heard what a noisy timing chain sounds like but there is no audible clacking or rattling from what I can make out at idle. I just assumed that it should be tight enough so that a finger poking at it could not wiggle it back and forth, and even a bit of side to side play on the cog. I'll try to post pics later today as it is hard to pinpoint exactly with words. I'm just wondering if my tensioner is failing, I know the car has much over 200K and most likely has never had any internal work done to it. I also can admit that from the seat of pants feel the power falls to almost nothing past 5K RPMs. I remember it being able to pull much more past that all the way to the red territory when I first got it. __________________ \|_1st-1980 280CE=TOTALED_\|_2nd 1999 C280=TOTALED(rollover)_\|_Current 1986 300E=She lives! 160K_\| Visit RHW's, aka Rich's Website For More Pics! Thanks to Zorro For Sig Pic!

08-08-2009, 11:45 AM	#4
appatula Super Member Join Date: Feb 2007 Location: Connecticut, New Haven Posts: 755 Drives: 1986 300E	Thanks to your picture I can clear everything up! The chain part with the black housing over it on right side of this picture is where mine seems pretty slack. I stuck my finger down in there as the cover was still on but it did seem loose? Could make some sense as the tensioner is on the other side? __________________ \|_1st-1980 280CE=TOTALED_\|_2nd 1999 C280=TOTALED(rollover)_\|_Current 1986 300E=She lives! 160K_\| Visit RHW's, aka Rich's Website For More Pics! Thanks to Zorro For Sig Pic!

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08-09-2009, 07:43 AM	#5
epowers777 Senior Member Join Date: Apr 2008 Location: Forethill, Ca Northcal Posts: 395 Drives: 1986 300E Benz 1991 300te 4matic	Theres probably slack from your cam cause the valve springs. turn the engine with a ratchet over a couple times. feel chain again should be tight. If you can here the chain slapping around worry. Also turn engine inspect chain for any wearing marks. chains also stretch. Do a google search might help!!

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