Just did this on my new-to-me '03 540i M-Sport. As you can see from the old vs. new comparison, the 72k mile TC tensioner spring is greatly compressed, which could be the leading cause of TC slack, allowing the "floppy" chain to damage the TCG's. This is the best 10-minute preventative maintenance you could perform to prevent premature TCG failure on your ride IMHO...
So you can see the location, I snapped a couple of pix using my mirror. The external TC tensioner is just under the front right VC's corner...
Last edited by ViolinARC; 06-14-2016 at 06:03 PM.
'00 540iA Sport w/235k+ Original TCG's, Vanos and transmission.*Trans failure at 244k+...FS Now
The spring actually isn't all that compressed, it was actually a design change in recent years. The older tensioners that originally came with these cars had a shorter spring, but BMW noticed a lot of complaints about startup rattles due to lack of oil pressure in the tensioner, so they made the spring longer to compensate for that. I had a 2003 540i/6 M-Sport as well, and I compared the original tensioner spring to the new tensioner spring:
Photo Sep 13, 11 34 10 AM.jpg
1995 525i 5-speed - Thread
Yep, they made it significantly longer. With the old tensioner spring, it didn't provide much tension when it wasn't full of oil, so on cold startups the chain would slap around pretty violently, hence the startup rattle that everybody complains about. The new, longer spring gives the chain a little more tension when there's no oil pressure, therefore it doesn't slap around as much on cold startups. That's why it's always recommended to change the tensioner on every 540i that still has the original one. You changed yours a while back on the 2000 540i, and that may have been a contributing factor to it running for 230k miles on original chain guides.
1995 525i 5-speed - Thread
Hello everyone! First post although I have been stalking the site for the past month or so. Incredible information here! Purchased a pristine 01 anthracite 540i ablout 2 months ago. Love the car! Just turned 100k. 2 owners who took impeccable care of it. Regarding the tensioner replacement, is it to my advantage to pull the fuel pump relay to "prime" the tensioner before the first start? Also, need to find the torque spec on the tensioner unless someone knows it. Thanks in advance for all of your future (and previous) help.
Rich
First post for me. Have a 2001 540i6 with 172K miles. Had it for 6 months/10K so far. Changed the tensioner 2 days ago. The old spring was the the longer newer style, and only slightly shorter than the new one. So I still have the slight rattle on start up for approx. 1 sec. I am guessing the chain is stretched enough now that the tensioner can't take up the slack without oil pressure.
Anyone ever tried putting a "spacer" in one of the bores of the tensioner to make the spring "longer"?
It's most likely your vanos. Have the guides ever been done?
At 172k your living on borrowed time.
Thanks for the quick reply. I don't know if guides or vanos were done, and i'm not afraid of tackling either, just want to troubleshoot and plan accordingly. It only just started with the rattle recently, so previously I was crossing fingers the work had been done by a PO.
+1, without records or a tear down inspection, assume nothing. What PO wouldn't tout the fact they spent thousands fixing the car when later selling it?
- - - Updated - - -
Maybe, maybe not. I had the start up rattle (intermittent) for years. I changed the timing chain tensioner at around 90k miles and 170k miles preventively. My guides finally let go at 260k miles (DEC 2016)...what a racket! Just turned 265k miles recently and life it good....on new guides, new tensioners, new chains and rebuilt vanos.
2001 540 M-Sport (cdn), ST X (KW) coilovers, H&R 15mm spacers, Eibach anti roll bars (28mm/18mm), Beastpower rear antiroll bar brackets, M5 rear chassis reinforcements (traction rods), Strong Strut front upper strut bar, Dinan Stage 1 software, factory M-Audio subs, Bavsound speaker upgrade, Bluebus bluetooth integration, Stop Tech SS brake lines, ATE coated brake rotors, ATE ceramic brake pads.
So I had my TCG's and VANOS done at my local indy. I have about 800 miles since the work was done. I'm still intermittently hearing the rattle at start, and some noise at idle. Does anyone know of a link to a video of what this motor might sound like with high miles and a properly operating VANOS? This is what mine sounds like. https://youtu.be/dfYPBfnIDvE
Working as intended
BIMMERONLY did my chain guides and vanos. There in fremont,CA, Great job and great on the price!
I have two 2002 540, mine topaz 6spd 97k,wife's Sterling AT 103k
replaced both ,hers is stone silent never rattles,mine still rattles cold start fairly consistently .
what gives? Should I be concerned? I am!
TIA
Gents - I just did the same to my 540i. The old tensioner was collapsed. The new one was much longer and had much more spring to it. The car is running great after the change.
My question is about the old tensioner. I took it apart. Cleaned it thoroughly with brake clean. Lubricated it with motor oil and now it appears to be functioning again. Does know if something mechanical causes these to fail or it it simply dirty, contaminated oil clogging some of the passage ways?
Does anyone know the most common reason for the failure of this important part?
You have to pull the fuel pump fuse and let the engine stop once its ran out of fuel. Then try and start a few times to get rid of all fuel pressure. Only once this is done you replace the tensioner. The idea is to be able to turn the engine without fuel on startup with new tensioner installed. This allow oil pressure to build, so that you dont have sloppy chain guide on initial startup that will do lots of damage to old guides. Then install the fuel pump fuse and off you go.
Just performed TCG and full chain replacement. VANOS gears were refurbished by JimLev. Can't recommend him enough. I used the Schawben M62tu Timing tool kit. I was a bit nervous due to horror stories regarding CEL and codes related to timing. None of that has happened and I'm confident if somebody were to use them and follow the directions related to timing procedure you will not go wrong.
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