Timing Chain Guides and VANOS - A Couple of Questions....

[Antipodean]

Most E38's will eventually have this issue, since the guide plastic inevitably wears out and breaks apart. However, the older pre-Vanos E38's usually go for longer before the guides fail, and there are a few E38's that will likely never have the issue: the 1995 740il, because it uses an M60 engine with a double timing chain, and the 1995-2001 750il, because the M73 engine only has one timing chain that's not prone to guide failure. So if you never want guide failure, buy either a super old 740il, or any 750il.

My own experience here was that the guides actually showed pretty minimal wear. In replacing the guides on the cam-to-cam tensioners, the guides broke apart easily and seemed brittle. So that seems to confirm that failure mode is disintegration of the plastic parts with age rather than wear.

[kahlilj]

Since 2009 you spent only 4500? You are lucky my friend

true, but he did mention it was initially purchased for "occasional" driving but it's now his daily driver. I did the same when I got mine in '07 occasional use (maybe 5K-6k miles per year?), but now its my DD and obviously O&M costs have gone way up.

Got a question for y'all: Is there an audible way to know the TCG's are going bad? Would this be the Vanos rattle I've seen mentioned before (that is, take a cold engine and listen for a rattle on startup)? I just want to know if there is a way to know if the guides need to be replaced before failure?

[dannyzabolotny]

true, but he did mention it was initially purchased for "occasional" driving but it's now his daily driver. I did the same when I got mine in '07 occasional use (maybe 5K-6k miles per year?), but now its my DD and obviously O&M costs have gone way up.

Got a question for y'all: Is there an audible way to know the TCG's are going bad? Would this be the Vanos rattle I've seen mentioned before (that is, take a cold engine and listen for a rattle on startup)? I just want to know if there is a way to know if the guides need to be replaced before failure?

Timing chain guide noise is distinctly different from Vanos noise... it's more high pitched and metallic, and unlike Vanos noise it doesn't go away once the engine is warm. The easiest way to check on your guides would be to drop the lower oil pan and check for plastic pieces. You'll often see plastic pieces before you hear any noise. If you hear timing chain guide noises then you should probably stop driving the car until the guides are fixed.

[NordmanMg]

Vanos rattle on startup is a sight of close-to-fail U-rail. Why? Because when U-rail is almost gone (you might still have NO plastic in a pan) it causes longer distance between right and left banks, however ECM trying to compensate that loose in length by adjusting the bank one vanos which after you stop the engine live you a gap in the vanos unit, that causes ratle on startup until vanos unit get filled up with oil,
more vanos unit worn more noise it couses

[kahlilj]

Timing chain guide noise is distinctly different from Vanos noise... it's more high pitched and metallic, and unlike Vanos noise it doesn't go away once the engine is warm. The easiest way to check on your guides would be to drop the lower oil pan and check for plastic pieces. You'll often see plastic pieces before you hear any noise. If you hear timing chain guide noises then you should probably stop driving the car until the guides are fixed.

Wait, timing chain noise is DIFFERENT than vanos noise? I thought the timing chain noise was BECAUSE of vanos? I'm all confused now.
So then is the startup rattle/noise that I hear or have heard mentioned before vanos? & if so how do you fix it?

Seeing plastic pieces in my oil pan is what I want to avoid. At that point the guides have already begun failing. Is there no other way to detect the guides going bad? One mechanic told me that rattle on cold startup was the from guides going bad. but you're saying that is not the case?

I also saw this thread about fixing a start up rattle noise too: http://www.bimmerforums.com/forum/sh...t=vanos+rattle

[NordmanMg]

TCG noise coming from chain-to-chain rubbing, when there is no plastic left on U-rail it couses "scratch" on chain and tensioner pushes chain onto u-rail

[dannyzabolotny]

If your 740 has 150k miles or more, then you just have to be ready for the possibility of guide failure at any moment. That's why these cars are going for so cheap nowadays, as well as the reason the junkyards here are full of them.

[garycw]

Since 2009 you spent only 4500? You are lucky my friend

When I bought it had 125k in '09. It now just has over 131k. Less than 1000 mi @ yr average. Had a very good dealer service history, and w/ radiator replaced. I've had new water pump, some little plastic fitting on bottom leaking coolant, belt, plugs, valve cover gaskets, all control arm bushings, tie rod, cam pos sensor, rotors turned, all filters & new tires to name a few.
It's all good now, just the timing chain & vanos worries me. I'd love to upgrade to a '01 750il in same color

[NordmanMg]

ok, this is what i mean, when you start hearing vanos noise on startups, its a sigh of
1) bad vanos unit or
2) possibly close-to-fail U-rail

and if U-rail failed then TCG noise coming from (see pic)
here where chain starts rubbing on chain when there is no more plastic on the U-rail
on the pic is my 540's engine with new guides and chain, and chain is tensioned.



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When I bought it had 125k in '09. It now just has over 131k. Less than 1000 mi @ yr average. Had a very good dealer service history, and w/ radiator replaced. I've had new water pump, some little plastic fitting on bottom leaking coolant, belt, plugs, valve cover gaskets, all control arm bushings, tie rod, cam pos sensor, rotors turned, all filters & new tires to name a few.
It's all good now, just the timing chain & vanos worries me. I'd love to upgrade to a '01 750il in same color

Oh, that make sense then

[cazal740i]

Vanos rattle on startup is a sight of close-to-fail U-rail. Why? Because when U-rail is almost gone (you might still have NO plastic in a pan) it causes longer distance between right and left banks, however ECM trying to compensate that loose in length by adjusting the bank one vanos which after you stop the engine live you a gap in the vanos unit, that causes ratle on startup until vanos unit get filled up with oil,
more vanos unit worn more noise it couses

Not true.. It maybe a sound for some m62tu engines, like yours, but not in my experience .I had average Vanos rattle @150k...It got worse at 170k...So at 177k I was under that same assumption that my guides must be toast too..I decided to undertake the Chain guide overhaul. I was impressed not 1 piece of plastic was on the oil pan. Inspection of the whole rail system was 100% perfect.. My engine internals was a rich Gold, chalk that up to regular Oil intervals, but as soon as I started to remove the guides they started cracking. I was close for them to fail but again it had nothing to do with my Vanos rattling.. The cyclone neck shattered in a million pieces. Im glad I did the job..
I used for 1st time Castrol full Synthetic since my Oil cap says so. My rattle was still there. I used to use Mobil 1 full synthetic 5w 30...So I decided to drain the oil and put back Mobil 1 5w 30...Ahh back to normal... Rattle start ups came back around 190k after another oil change ... I added more Mobil 1 5w 30 a little bit above full line and the Vanos are once quieter on start ups... I still have the Vanos rattle at idle but glad the start upo noises are gone. Now im at 200k but Ill be sending my Vanos to a BFC member here to change out my seals..

[NordmanMg]

try to add Lucas Synthetic oil stabilizer, it works

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if you think that m62 timing is suck, then you never seen Audi one lol

[garycw]

That looks like something from another planet to me

[purplecty]

And its on the back of the engine correct?

[NordmanMg]

yea you can see the headers

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[cazal740i]

Ferarri Enzo- Chainless.... Timing GearsRT7Xqco.jpg
Timing belts front.jpg

[NordmanMg]

This is seems pretty reliable, but on the real life not that much
like on this picture you can see the reason they took timing case apart
shredded oil pump gears from CrankShaft to oil pump

[dannyzabolotny]

I remember when I first saw what the timing chains inside an Audi V8 looked like... that pretty much ensured I will never ever buy an Audi.

[Antipodean]

Finished buttoning it all up this weekend. Filled with fluidsh, reconnected the battery and started it up. Oil pressure came up nicely, a couple of initial rattles but very quickly smoothed out. I have not road tested the car yet, as I still want to run it up to temp, and fully bleed the cooling system, as well as check for leaks. But so far we are looking good. Anything else I should check before hitting the road?

[clarkitect]

Nice work! I think I was so giddy at the accomplishment I took mine out within an hour of starting up. What to check? You probably checked the heck out of things before turning the key. Coolant bleeding, leaks, check the belts and stuff and go for a spin.

[racer2086]

Just drive it a little bit and check in a couple days. I ended up having a slow coolant leak out of my lower radiator hose because I didn't crank the hose clamp down enough. Good job. It's such a great feeling.

[Antipodean]

Thanks guys. I have to say it was a lot of wrenching - more than I was expecting. Setting the timing and torquing up the cam bolts was a bit disconcerting (110Nm on a hex bolt seems a lot. Kept expecting something to strip). And the torque to tighten the crank bolt 60-60-30. Crikey! Had a bit of the Ship Wrights disease kick in also, and rebuilt the heater valve, transmission cooler thermostat and all the power steering hoses while I was in there (all a lot more accessible with all the other bits out of the way). So that made for more of a project than the usual. All looks good though but am going to wait for the weather to improve before taking the car for an extended run. We just had two snow storms and the roads are a mess, but am curious to see if I'll notice a difference.

[Antipodean]

So gave myself quite a scare this weekend. Fired up the car again (2nd time since the new TCGs), and the engine would not turn over! I could hear the starter motor trying, but seemingly not having enough torque. Checked the battery cables and voltage - all was fine. Tried again and this time it caught. Ran but was really rough, also lots of smoke out the exhaust - and then a "check engine" light.

This was not good. Shut it down and thought about what it could be. I had turned the engine a couple of times by hand, so felt confident it was not the timing and valve interference (very scary). So took a deep breath and started to diagnose.

First pulled the codes - P1356 - miss-fire on #8, and P0492 - insufficient aux air flow on Bank 2. This last one seemed odd. If the air pump had failed I would expect an error on both banks, or rather than insufficient air flow, could it be too much fuel? So the other piece of information here is that a couple of the fuel injectors were damaged when I pulled the fuel rail (the retaining washer for the rubber o-ring into the intake manifold broke - just old and brittle I think) so I replaced all 8 with remanufactured injectors. If one of those was sticking open that could well explain this.

Next step was to pull the spark plugs and run a compression test. When I pulled the plug on #8, sure enough there was gasoline on the plug and in the chamber. Bingo! The injector had failed open, and was dumping fuel into #8 cylinder. This meant the engine would not start as it was trying to compress gasoline and then misfired when running.

I put a squirt of oil into #8 as the gas had probably washed it down, finished the compression test (all were between 180 and 190, so good), and ordered new replacement injectors. Am not trusting the remanufactured ones again!

So lesson learned, but another week to wait till I can get the car back on the road. Rather that than killing the engine - which would have been the case if I did not catch the injector failure early.

The battle goes on.

[HDIDDY]

I bought my 00' four or five years ago with 80k. Started hearing some vanos rattle around 140K. Lucky enough to find a member here that do my guides when I made a trip up his neck of the woods. I regularly changed my oil every 8-10K with mobile 1. GSXR said the guides would only last a little while longer. Inside the engine was immaculate, even had members PM and ask what oil I used.

[purplecty]

I bought my 00' four or five years ago with 80k. Started hearing some vanos rattle around 140K. Lucky enough to find a member here that do my guides when I made a trip up his neck of the woods. I regularly changed my oil every 8-10K with mobile 1. GSXR said the guides would only last a little while longer. Inside the engine was immaculate, even had members PM and ask what oil I used.

I was one of them haha your engine internals are mr clean clean!

[dville]

Why mess with the VANOS and timing (I am curious)? Can I just replace the plastic guides and the chain to chain tensioners and be done

Timing Guide center - 11311741777
Drive Side guide rail - 11311745406
Pass side guide rail - 11311741236
1-4 chain tensioner - 11311435026
5-8 Chain tensioner - 11311435027
Sliding piece (x4) 11311435028