Sierra VANOS Trouble Draining Gas and Wallet

Faced identical symptoms on my 2013 BMW 528i. The check engine light came on, accompanied by low power and rough idle. The VANOS system was failing, specifically the inlet camshaft solenoid valve. This is a known issue that affects several BMW models. The repair involved replacing both VANOS solenoids since they typically wear at similar rates. The mechanic also cleaned the entire VANOS unit due to oil contamination. The timing chain was inspected during the repair and showed minimal wear, so no replacement was needed. The job required specialized diagnostic equipment to properly test the VANOS system. Labor was significant since accessing the solenoids meant removing several engine components. This is not a DIY-friendly repair due to the complexity of the VANOS system and the precision required for proper timing adjustment. The symptoms match exactly what you describe, increased fuel consumption and timing issues. These problems typically worsen if left unaddressed and can lead to more serious engine damage. The repair is complex but essential, running with faulty VANOS can cause additional engine wear and performance issues. After the repair, fuel consumption returned to normal and the engine regained its smooth operation. The check engine light has not returned in the 40000km since the fix.

Thanks for sharing your BMW experience. I also had VANOS solenoid problems that caused low power and similar symptoms. Mine took around 4 days to fix since they found some oil sludge buildup while doing the work. Just curious, do you remember roughly what you paid for the full repair? And has everything stayed running smoothly since then, or have you noticed any other related issues come up?

My full VANOS repair ended up costing 250 Euro, which covered fixing the defective inlet camshaft solenoid valve. Since the repair was completed, the engine has been running perfectly with no engine misfire or related problems. The mechanic spotted the issue quickly, it was a faulty solenoid valve rather than a complete system failure, which kept the costs lower than initially expected. The timing chain showed no wear during inspection, so that saved some money too. Getting it fixed early was key, if left longer, oil sludge buildup could have made the repair much more extensive and costly, like in your case. The engine now maintains proper timing and fuel efficiency is back to normal. Its been over 18 months since the repair with no VANOS failure symptoms returning. The check engine light has stayed off and the engine runs as smoothly as when it was new. Early diagnosis really helped prevent more serious issues from developing.

Had my Sierra fixed last week after dealing with those variable timing issues. Took it to a trusted mechanic who diagnosed a failing inlet camshaft solenoid. The repair took 4 days since they found quite a bit of oil sludge that needed cleaning. Total bill came to 680 Euro, higher than expected but they had to do a deep clean of the VANOS system along with replacing parts. The timing chain looked good though, which was a relief since that would have added significant cost. The check engine light is now off and fuel consumption is back to normal. Engine feels much smoother too. Shop was upfront about everything, showed me the old parts and explained why the sludge cleanup was necessary to prevent future VANOS failure. Really glad I got it sorted before any major engine damage occurred. Been about 3 weeks now and everything is running perfectly. Worth every cent to have it done right and avoid bigger problems down the road.