Author Topic: replaced the tensioner, still as loud (Read 3989 times)

rojeho · « **on:** May 08, 2011, 10:31:15 PM »

Replaced the timing chain tensioner on a 93 318i with 109k. No change - it still rattles loudly - like you can hear it from three houses away sounding like a bad sewing machine / tractor. I guess this means that I need to open it up to look at the guides and the chain? Can I do this by just taking off the valve cover or do I need to do more? Any guesses on common cures?

One other note, the AC does not work. Pressing the AC button does not make the compressor engage. Any chance the noise could be related to the pulley? I'm guessing not.

DesktopDave · « **Reply #1 on:** May 09, 2011, 07:10:04 AM »

Yeah, I'd say it's time to pull that front timing case. Hopefully your chain isn't eating it from the inside out.

The A/C is likely just discharged. If the refrigerant is low, the system will not engage to prevent the pump from getting destroyed.

woof132 · « **Reply #2 on:** May 10, 2011, 04:37:29 PM »

you'll need to do more than just pop the valve cover. you'll have to drain the coolant, pull the thermostat housing, pull the crank pulley, and pull the upper and lower timing covers. there are three guides that this will reveal. the one that is operated by the tensioner, a long one on the drivers side, and a small, curved one below the crankshaft sprocket. On my car that lower one had broken into two pieces and the pieces would occasionally pop up and hit the chain and make an unappealing sound. but any of those three guides could cause the noise if they're excessively worn or chipped/broken/missing a mounting bolt.

Also, it is conceivable that the AC compressor could cause a bad sound. try removing the AC belt so the compressor doesn't drive, and see if that stops the noise.

mark_i · « **Reply #3 on:** May 12, 2011, 04:40:32 PM »

that is the noise an M42 makes before the timing chain/guides/sprockets let go. Plan to get the engine inside and follow the advice above before a $250 repair turns into a $1500 rebuild.

rojeho · « **Reply #4 on:** June 16, 2011, 10:24:34 PM »

I then took the valve cover off. I can see the timing chain guides down the sides and they look fine as far down as I can see. The cam gears don't appear to be worn. The part of the chain that I can see looks good. There is a slight amount of play/movement in the chain - like 1/16" or less.

I'm trying to decide what to do next. Do I just start taking components off the front of the engine until I make my way down to the chain and hope to see something amiss? Do I turn the crank to inspect the entire chain first? Is there anything else that could cause this?

Appreciate the help.

rojeho · « **Reply #5 on:** June 21, 2011, 01:09:39 AM »

Well, turns out I was a genius and didn't even know it. Before I tore in I put the valve cover back on took the drive belts off. Started it and nothing but a purr. Turns out the AC compressor pulley is able to spin free and it wobbles side to side enough to contact something else metal, giving a nice rattle that sounds just like a timing chain slapping against something.

DesktopDave · « **Reply #6 on:** January 04, 2012, 08:40:14 AM »

I just caught this post...figure I'd bump it, good info here. Spam from the dead, as it were.

Rojeho, is it all still running well?

Good catch...lucky too, given the reputation the M42 has for timing case issues.

318bud · « **Reply #7 on:** January 04, 2012, 03:30:23 PM »

mine makes a fast clicking/ticking noise as well. wandering what could be causing that.
belts are new and from what i remember the pulleys were running smoothly(i checked around summer time when i pulled off timing covers)

could it be lifter ticks?

DesktopDave · « **Reply #8 on:** January 04, 2012, 03:40:58 PM »

Might be. Could also be a loose bearing in the accessory drive somewhere.

locknload · « **Reply #9 on:** January 04, 2012, 09:26:47 PM »

I had that noise, but only at startup idle. Turns out it was the fan blades barely catching the hose clamps I had just tightened. Putting a few rev's on the engine was enough to flex the fan blades so I could never isolate the conditions. Rotated the clamps to move the barrel to the back side of the hose & all is quiet again.

PeabnutBubber · « **Reply #10 on:** January 04, 2012, 11:43:32 PM »

I'm jealous. I'm in the middle of the timing mess now.