Case Studies

BMW Engine Camshaft Bolts Problem – Repair and Correction

What Happens
Certain late model BMWs can experience a problem with the camshaft sprocket retention bolts failing.
This is a design defect, and well know in professional BMW service circles.
You can see on the photo below, that VANOS (variable valve timing system) to intake camshaft bolts have broken and backed out, 3 of the 4 bolts are damaged and loose.

BMW said “in very rare cases the bolts holding the variable camshaft timing (Vanos) unit housing may become loose or, in extreme cases, break.” In such cases, the driver would be alerted by a check-engine warning light. Power to the engine could be reduced and “if ignored, the problem can become progressively worse, eventually leading to no-start conditions, stalling and engine damage.” Vanos is BMW’s variable-valve timing technology.

The models affected by the recall are the 1 Series, 3 Series, 5 Series, 5 Series Gran Turismo, X3, X5, X6 and Z4 from the 2010-12 model years, as well as the 2012 6 Series.

Why Bad
It is important to correct this ASAP as it will allow camshaft to become unsynchronized with the crankshaft, pistons will strike valves and do massive internal engine damage. Or a bolt backs out and falls into the timing change, Either way, a very bad day.

Cause Of Failure
Signs and Symptoms of this problem include VANOS fault codes, rough idle, engine noise, knocking or clicking sound, maybe a rumbling noise. Then, if not corrected, the KABOOM. An expensive “KABOOM”.

If you experience any of the following signs, you may be on your way to bolt failure.
Call or stop by the Atlantic Motorcar Center so we can check out your BMW immediately.

  • Your check engine light comes on
  • You hear a knocking noise that sounds like metal on metal
  • You experience a great loss of power

The old bromide that “An ounce of prevention is worth a pound of cure” never rang truer than in the case of your engine’s internals. Proper servicing, which is all too often overlooked on today’s newer cars with their extended service intervals, will go a long way to preventing problems in the first place.

We strongly advise to all of our BMW and Mini Cooper customers, to consider changing the engine oil and filter every 5,000 miles. Following extended service intervals of 12,000 to 15,000 miles is a recipe for failure, setting the customer up for a very expensive, and very unexpected failure down the road. Nothing is less costly, or can do more to prolong the life of your car, than changing the fluid and filter (if equipped) on a regular basis, BEFORE failure.

Your Advocate, On Your Side
At AMC, because we are independent and locally owned, we are YOUR advocate, and our team makes a point of checking recalls and service campaigns from the manufacturer on every visit, and keeping our customers up to date.

Not a simple repair, yes, but one, if done correctly, will last several years. That’s our goal with BMW, and other autos here, fix it right the first time, and prevent problems from happening in the first place. 30 years of service experience have well taught us that “an ounce of prevention is worth a pound of cure.”

Be cured, once and for all, and give us a call, we’re happy to answer any service questions you might have on your BMW, Audi, Mercedes, Lexus, Volvo or Volkswagen.Earning your trust, every time you turn the car…that’s what we do…every day…for the last 30 years. Click here see what our happy customers have to say about us and our service at AMC Customer Reviews.

If you have questions, or if we can be of further assistance, just call us at (207) 882-969, we’d love to meet you, and your car!

Bruce and the AMC Service Team

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