I have a 2001 X5 which has recently started making a tapping noise that appears to be coming from the valves. I currently have about 96K miles and have followed recommended BMW maintenance closely. I have seen no low oil pressure warnings, there are no leaks, and I religiously check the oil level. Does anyone have similar experience - any ideas on the cause and what might be needed for repair? Thanks
Almost certainly a stuck/sticking hydraulic tappet (a/k/a cam follower or valve lifter). These are little oil-filled devices that sit between the camshaft and valve stems (one per valve) to eliminate any slack (lash) in the valve train. One or more lifters have become at least partially clogged by buildup from dirty oil and are not functioning properly. "Recommended BMW maintenance" is, sadly, inadequate: 15,000-mile oil change intervals are guaranteed to allow sludge build-up in varying degrees, more so if the engine is not driven hard. Is the ticking constant or does it come and go, especially with engine temperature (most noticeable on a cold start, diminished/absent when hot)? If it isn't constant or loud, it may reverse itself after a few oil changes: Change the oil now and every 5000-7500 miles thereafter using a top-grade synthetic oil. Clean oil, heat and time can sometimes clean the gunk out of a mildly plugged lifter. There are oil additives to deal with noisy lifters but they have their own risks (I'd consider them a last resort, for tight budgets). Unfortunately valve lifters are inexpensive parts ($30-ish) buried under a lot of expensive labor.
Thanks - really appreciate the advice! It is definitely noisier when cold, but still present when warmed-up. I'll start with an oil change as you suggest and drive it a bit harder too to see if that helps. Forgot to ask - any major adverse engine consequences if this doesn't work and I don't want to do a $1K+ repair?
Didn't see your edit until now, sorry. It can take quite a while for a sticky tappet to do any real damage but if you ignore it long enough, it will. The ticking/tapping/clacking sound you hear is that of the valve stem, lifter and/or cam lobe slamming together as the lobe begins to open the valve. The two main risks if left unattended are camshaft scoring/irregular wear (bad) and a mushroomed valve stem (worse). The louder it gets the less time you have. How long you can wait depends on many things, primarily how loud the noise is and how (and how much) you drive. Ask a mechanic you trust (and who knows BMWs) to take a listen and gauge how serious it is.
On my last 740 I had a ticking sound I thought might have been a "rap" or worn bearing in the crankshaft. BMW serviced it to the tune of 6K only to find out it was a timing chain rubbing. I had an add on service plan which covered approx half of the bill. I had to pay the rest out of pocket. The car had 85K on the odo at the time. They did a complete engine overhaul and a complete fluid change of the transmission as part of the repairs. I sold the car with 208k on the odo and both the engine and tranny were as sound as could be. I just want to point out that sounds are not always easy to diagnose... but it is best to pay attention to them. As NotTheStig says, have someone knowledgable give it a listen for the benefit of their experience... but even experienced people encounter new problems. I paid quite a sum to find out I had a rubbing timing chain... but I never had a problem with anything related to the engine's internals after that because of the quality of the overhaul they performed... so in the end I really did make out. BTW that is the same engine as was in my 740i, the 4.4L. Chuck
I have the same condition on my 2000 M Roadster. It doesn't do it everytime I start the engine. It may or may nor tick when cold started and not do so after the engine is warm. Or, it may tick for a few warm starts. You never know when it will do so. The tick goes away as the engine warms. I changed the oil and use synthetic. I also use S-100 fuel additive. I'd appreciate any advice.
For Stevewill and Ehackett - have a service professional look at your issue @ Stevewill: Your car is right at ten years old, and without a doubt, it likely has some wear and tear on its valvetrain. You could have a bad or worn valve tappet, or there may be another issue affecting it directly. For everyone else, this is just an illustrated example of how it's not always a valve tappet On the M30 and M70 engines (yes I know you have a different engine but bear with me here), there is an issue where the oil distribution tube that sits on top of the head can work itself loose. Not only can this cause the rattling noise your describe, but over time, it can cause excessive wear on the camshaft since the valvetrain is no longer getting oil where its supposed to. The oil distribution tube is mounted on top of the M30/M70 head using bolts that can come loose. Not sure if the S50/S52 engines have a similar issue, but I describe this as an example of how a supposedly unrelated issue can make it seem like you have a bad hydraulic tappet. You can go to http://www.bimrs.org to have this looked at by a competent, independent BMW service professional.
