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I sent in my 2003 4.4 for a vanos gear swap after running on bad seals for about a year. Now the mechanic says I need to replace my driver side head. Hes basically saying the bad vanos affected the cams and wore them down. He says its better to go ahead and swap out the entire head instead of piecing it together. How is this possible?

Can someone explain the consequences of running on bad vanos seals? It seams the only complaints are the vanos groan on start up and diesel noise upon acceleration. What exactly happens to the gear when the seals fail and how does it effect the rest of the motor?
 

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2002-2005 Range Rover MkIII / L322
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I don't think the mechanic is advising you correctly. The Vanos is at the end of the cam and there are multiple cam caps holding the cam in place. The cams should not wear beyond the first cam cap - if it was worn in this manner the car most likely would have been coding like crazy besides running poorly and making a ton of noise.

Did you do an oil pressure test? Can you get some pictures and post them?

My understanding on the Vanos internal seals - when they start to fail they get noisey. I have never heard of this, but thinking it through, if they really fail they cannot build up enough pressure to advance or retard the timing as instructed by the engine computer. You should have been getting codes in this case. Did you have codes and ignore them? At this point the engine should have gone into a loop mode and not used the Vanos at all. I think the Vanos would just go all the way in one direction (don't know which one) - there are gears in there which would limit movement. I suppose it is possible the plastic pieces of the Vanos wore and/or cracked into pieces and the entire unit would wobble, but the car would run just awful and throw codes. When my Bank 2 vanos bolt came loose, the Vanos moved all the way to one side and the engine would not start.

Maybe someone will chime in with more thoughts. I have rebuilt 6 Vanos units, and done head work on three engines - I am having a hard time buying into what your mechanic is saying. S/he could be correct, but I need to see more proof. More background on how the engine was running and codes would also be helpful.

Get some pictures of the issues and you will get more responses.
 

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2002-2005 Range Rover MkIII / L322
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The only way it could affect the heads is if the timing is completely off and the valves smash into the pistons. Otherwise a worn-out Vanos will not cause any harm, just some extra noise. Sounds like your mechanic might not know what he's talking about, I'd try and get a second opinion if possible.

Also, even if the cam was somehow worn down (which I've never seen in the dozens of M62tu's that I've rebuilt, including ones with 200k+ miles), it's pretty easy to find a used cam and pop that in without replacing the whole head. Replacing the head is pointless unless there's actual valve damage.
 

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I agree with the two previous posts. The likelihood that a Vanos seal damaged your head is little to none - see kg74 response for reasons why.

What symptoms are you experiencing with your engine, are there any codes that you can share?
 
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