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Dr Side VANOS Failed:P0021

1736 Views 8 Replies 3 Participants Last post by  mjrgroup
2005 RR (M62TU): So when I replaced my chains and guides, as well as rebuilt my VANOS several years ago, I noticed when I torqued the Dr side VANOS back up that it had a bit if play. I've been receiving P0021 for the last six months, and my guess is that VANOS (Bank 2 Dr Side) is causing the problem. Been thinking thru the procedure, and I know that I need to remove both valve covers, lock the cams and crank at TDC (compression stroke), as well as removing the Dr side upper timing cover. My question is, in order to gain sufficient slack in the primary chain (secondary chains i do not believe have to come off) can I just remove the main tensioner that's on the Pass side, and should that allow enough slack to remove the VANOS? Planning on dong it this weekend, just wanted to think thru the procedure first though....

PS: I did check the timing wheel thru the inspection hole with an allen key, and it's a bit off, I am guessing 1-2mm, which is about how much play the VANOS had when I tightened the nut.
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It is unclear what step you are trying to avoid or parts you do not want to remove. So here are two thoughts:

1) To properly time the engine you need to start with Bank 2, and then do Bank 1. So working on only Bank 2 only is not an approach I would take. The slack is taken up from Bank 2, when Bank 1 is adjusted, plus the timing chain tensioner. I messed up on one run, doing Bank 1 first and ended up having to go back in. In addition, I have read people speculating that doing Bank 1 first and having the slight slack can lead to the vanos bolt loosening. (I had this happen also, but I did Bank 2 first).

2) Be cautious rebuilding your Vanos again, the plastic innards may be past their serviceable life.

You can pull both valve covers and the oil feed tubes, pin the engine and put on the block and then check through the upper timing cover timing hole. What you are seeing now may just be the valves fighting and causing the trigger wheel not to line up. I think the best way to check it is to put the timing blocks on. Either way, with the valve covers off, at least on Bank 2, you should see if you have a vanos issue.
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So I worked on it late last night and this is what I did in the following sequence:

1) Removed both Valve covers.
2) Rotated Engine to TDC on Compression Stroke.
3) Pinned the Crank.
4) Installed locks on Bank1 (Exhaust and Intake Cams)
5) Installed locks on Bank2 (Exhaust and Intake Cams)
6) Removed Bank 2 Upper Timing Cover.
7) Noticed that the Timing wheel for Bank2 is off several mm, again, I think this is due to play in the VANOS.

I am not going to try and rebuild the VANOS again, already ordered one from Dr Vanos.

Now, What I want to do is to replace the Bank2 VANOS, if possible, Without removing the Upper Cam cover and VANOS on Bank1. I am thinking I can remove the Main Chain Tensioner on PASS side, and that should give me enough slack so that I can replace the VANOS on Bank2. If not, I guess I'll have to remove the Upper timing cover on Bank1, and Loosen VANOS CAM bolt so the gear with rotate to allow chain slack, I was just trying to avoid this.

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See what I wrote in #1. Bank 2 first and then Bank 1 - you need to remove the upper timing cover on both sides or you cannot get the bolts out. Loose enough to freewheel should be fine on Bank 1. Look at the procedure in RAVE and notice the sequence. Beisan's write up also mentions this. Can you technically do it, yes - is it worth the risk of throwing an under/over advanced code or having the Bank 2 bolt coming loose down the line? No. The upper timing cover is not that hard to take off.

Is the Bank 2 trigger wheel loose? Did you try putting torque on the outside nut?

Post some pics of the old vanos if it shows any reasons of failure when you are done.
Yeah I installed the cam locks in opposite sequence. Did not think it mattered, as they all went on very easy, just had to rotate Intake Cam on Bank 1 a bit and lock slid right on, which I believe is normal on that cam due to lobe tension on lifters. Also, on GAS site, you can just use one pair of locks and do one side at a time as well:


I thought that if I removed the tensioner then I could lift the chain over the sprocket on Bank1 to give me enough clearance on Bank2 to remove the VANOS, but then I figured I would risk not being able to get the chain back on Bank1 with sufficient tension to keep the engine in time when I installed the tensioner and removed the cam locks. I think, much safer as you say, to loosen VANOS on Bank1 to allow freewheel when I retention the chain.

I don't see the risk with Bank2 bolt coming loose, as regardless, I have removed Bank2 Cam cover to allow for Bolt and VANOS removal.
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The order of cam lock installation is not really important. What is important is the tightening of the vanos bolts - here you want to do Bank 2 first, to take up any slack. Then Bank 1 - the timing chain tensioner adjusts for this slack. As the Bank 1 vanos still freewheels one can achieve optimal chain tightness. This will account for any chain stretch and vanos play due to wear and tear.

You can do what you describe, but what I just explained above, will not happen. I have changed the cam chain tensior on Bank 2 without disturbing Bank 1. As I knew the slack was already taken up correctly, 3k miles or so before, I was not worried. But in your case, from the start you have questioned the amount of play in your bank 2 vanos, which you do not want. The chain when new is a fixed length, after loads of miles it stretches.

Best do it by the book, and not have to go back in b/c of cam timing codes.
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Thanks. I agree, I'll remove Bank1 Cam Cover and loosen Bank1 VANOS, replace Bank2 Vanos, tightening Bank2 first, then move to Bank1.

Have you every just used the Cam Cover holes to set the timing wheel as opposed to the tool?
I use both. The built in one as a double check. There are two problems with using the upper timing cover - first is you cannot get a torque wrench on to tighten the trigger wheel and second is you cannot have the rubber gasket installed because it has to be pushed down. As a double check, I install the upper cover without the gasket, level it with the head and then check. When happy, I remove and install gasket with RTV.
@timc, did you ever fix the P0021 code? What was the issue and what was your fix?
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