The hydraulic lifters on my '07 Z4 3.0i (Sports Package) were replaced yesterday and I am trying to determine whether the engine is sounding better. I am probably over-analyzing, but I wanted to seek feedback on this anyway: I have noticed that the steering has a vibration that almost seems like I can 'feel' the engine. I feel the vibration when the vehicle is stationary. The vibration isn't bad, but it's definitely there. What I want to know if if this is the sports car feel or if something with the lifter replacement didn't go as planned.
power steering That's probably feedback through the power steering. Changes in pressure/volume follow the changes in engine speed if the idle surges. It should smooth out at normal speeds. Also even a light tough on the steering wheel can make it work just slightly. If it annoys you ask the tech to check the power steering. Chuck
Thank you for your response. What you have described are exactly the 'symptoms' I am experiencing. It doesn't really annoy me (yet) but I will watch this behavior. Can you explain what you mean by "changes in engine speed if the idle surges"?
When the engine is cold, the idle speed fluctuates. It is a function of the amount of air and fuel being metered in but on some systems more air is getting in through various emission system valves opening and closing as well. This air passes through the "vacuum system" and bypasses the air flow sensor. When the engine gets up to temp these adjustments pretty much stop and the engine speed smooths out. It's true of most cars not just BMW's. If one of these valves is malfunctioning then these fluctuation/surges can happen when the engine is fully warm, and it is a sign that the system needs some technical assistance. These particular problems are subtle and a pain to pinpoint. We had one that turned out to be a pinhole leak in the brake booster diaphragm. To diagnose you have to start at the point of supply for the manifold vacuum and work backwards... disconnecting and plugging the paths to determine which path points to the culprit. The culprit path is the one where the bad behavior continues. Where it really gets interesting is when there is more than one culprit! Chuck
Thank you for taking the time to explain. I definitely am experiencing the surges when the engine is cold and I am not alarmed since you described that this is expected behavior. On the second symptom you described, I have not experienced this, but have noticed some surges in Sports mode when I sometimes feel the vehicle (not just the engine) surging / lurching especially when at slower speeds.
Just a thought, but on my previous Z4, I experienced a similar experience. There was a problem with the valvetronic ( variable valve timing) which was fixed by the dealer. It was a very subtle vibration when the car was not moving but disappeared when the car was moving. The SA said that only one out of ten owners would have even noticed it.
Quick update: I will be taking my vehicle in today to get this checked. I originally scheduled to go on on Saturday, but the problem has become to bothersome that I requested the dealer to bring my appt forward. I will post updates soon.
Got a call from the dealership informing me that they want to the replace cylinder head. Apparently they don't have the part and want to keep the vehicle for 4 - 5 days while they source the part and install it
The plot thickens :-( I was all set to take delivery of my vehicle with the new cylinder head this afternoon and got a call from the dealer informing me that the water pump was failing and needed to be replaced. Apparently, they discovered this problem AFTER test driving the vehicle. I am relieved that they found another problem before I took the vehicle home, but am also disappointed that they found this problem so late in the troubleshooting process. I take delivery of my car this evening and will post back.
That's very possible... especially if the service tech had a reason to suspect the lifter situation was the source of the problem . I had a 1999 Harley Ultra glide that began making a strange engine noise, and the service tech was 99% positive that it was the altenator, since they had seen several bikes in which that was the case. After replacing it, the noise was still there. Turned out to be a damaged rod bearing, which they fixed under warranty.... even though the bike was beyond the warranty period. Sounds to me like the dealer is doing his best... Some dealers would simply have returned the car to you to see what you would do next. Good luck!
Another update - my vehicle is still idling very rough. I am taking it again on Tuesday. This is really frustrating. I haven't had the car a year (bought CPO in August 2010) and I have had to take it back for various things almost 7 - 8 times already. My co-worker who drives a Mazda Miata is laughing very hard.
I really don't think water pumps give you much of a warning. I heard rattling like I was dragging a string of tin cans. Pulled over. Smelled antifreeze and saw antifreeze leaking. All happened within a minute.
Update: Had to take the vehicle back AGAIN because the problem wasn't resolved. The latest update I have is that the tech believes that the injectors are not receiving enough power but they don't know what the fix for this is yet. They are working on the issue and will keep my vehicle until the problem is resolved.
