Merc Variable Valve Timing Vs Vanos

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Only on certain M-series engines.
I've never heard of mechanical failure on the BMW forums for IL6s.
The seals on the other hand do need renewal.
The procedure section of this website shows how to do it

http://www.beisansystems.com/


They can hydro lock the I6's and are prone to this. Its a good idea to check the oil regularly on them, and check for a milky residue. Its usually avoided by regular use to be fair but a fair few 3 litre X's has this trouble.

The newer valvetronic engines (4 pots and some 4.4i V8's-the 330bhp ones not the weedy 286bhp ones) seem fairly strong and trouble free. The valvetronic cars are more powerful and more economical too.

if MPG is such an issue for the OP-there is always a nice reliable torquey CDi ;)
 
im no expert but i remember changing the seals on a 325 cost me 2 days labour, some funny special tool, programming by the dealer (extortionate) and the price of the parts...

It takes a DIY type like me with no experience the whole day to do. No special tools or coding are required because you are not altering the timing, just putting the old unit back on.

BMW prefer to sell you a complete new unit because it works out 6000% more expensive !

The site I linked has the most amazingly thorough belt and braces 'how to articles' I have ever seen.
 
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They can hydro lock the I6's and are prone to this. Its a good idea to check the oil regularly on them, and check for a milky residue. Its usually avoided by regular use to be fair but a fair few 3 litre X's has this trouble.

That's caused by extended oil drains using rubbish semi-synthetic oils like Magnatec.
The CCV valve needs to be working and not blocked with mayonnaise otherwise the car will start ingesting oil.
 
That's caused by extended oil drains using rubbish semi-synthetic oils like Magnatec.
The CCV valve needs to be working and not blocked with mayonnaise otherwise the car will start ingesting oil.

Semi synthetic is fine so long as its changed regularly. BMW recommended magnatetic but the car needed 1litre/1.5k miles so I ran it on fully synthetic Mobil 1.
 
This is only my experience from the E39 M5 but as a 5.0 litre NA engine, the Vanos system and any possible flaws are a small price to pay for an engine which makes the Merc unit seem pretty limp wristed in comparison.

The Vanos issue is also largely exagerated by the BMW code of practice that was to change out whole units when any sign of trouble was found.

Dave!
 
This is only my experience from the E39 M5 but as a 5.0 litre NA engine, the Vanos system and any possible flaws are a small price to pay for an engine which makes the Merc unit seem pretty limp wristed in comparison.

The Vanos issue is also largely exagerated by the BMW code of practice that was to change out whole units when any sign of trouble was found.

Dave!

Agreed - the first garage I went to said that they are all noisy, and the second garage changed the units for me. At an M5 meet we popped our hoods to compare and some 100k milers were quieter than a 5k miler. They did mod them at the 00 facelift to include an oil nrv to stop the oil draining away when switched off.
 

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