Is the N52 generally tappy?

C

cooots

Member
Hi,

I went and had a look at a pre-owned Z4 Coupe 3.0si with 43,000kms (22,000miles) today - I'm quite interested in buying too.

When I inspected the car, one thing I was particularly listening for was the dreaded hydraulic valve adjuster tapping noise that my research tells me is common with the N52s.

When the car first started up I heard it for a split second, but it immediately went away and didn't come back for the next 2 hours I was looking and driving the car for (salesman told me it was only because it hadn't been started in ages).

I also noticed that the motor still sounded a little tappy in general - the sound was consistent, but it definitely had a mild tap to it. You could hear it with the bonnet open, but not with the bonnet closed.

I was hoping you guys could let me know if I should be concerned about the initial start noise, and the general tappy sound of the motor that followed.

I'd appreciate any help.
 
i would be very carefull with this car

http://www.z4-forum.com/forum/viewtopic.php?f=3&t=10937#p161535

http://www.z4-forum.com/forum/viewtopic.php?f=2&t=26091
 
Hi coots

I have the same engine / car, 2007 with 40,000 miles. I use the car for my small daily commute of 2.5 miles each way and suffer from HVA noise now and again. A slightly longer run, or revving the engine when the oil is warm(!) sorts it out, and the engine again sounds like a 3.0 litre premium car engine should. The engine probably does it about once or twice a month, usually after it hasn't been driven over the weekend and having not had much of a run during the week.

I believe that HVA noise can sometimes be sorted under BMW warranty as they changed the design of cylinder head for later cars, incorporating a non-return valve to prevent the oil from draining when the engine is off, and that eliminated the noise. My cars is more than 3 years old and was purchased from a non-franchise dealer :roll: so I don't have a BMW warranty, so I think I'm going to have to live with it. I don't want to fork out a fortune for the parts and labour to install the redesigned cylinder head. I do have a non-BMW warranty from the place I bought it from so I could always look into that if I feel I can't live with it any more.

When the car first started up I heard it for a split second, but it immediately went away and didn't come back for the next 2 hours
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If the noise goes away but then returns having been driven for a fair while, that's not the usual HVA noise problem and I would leave the car well alone. One thing to note is that a rattle that does not go away can indicate a blocked oil feed or that one or more of the lifters has collapsed due to wear and is no longer opening its valve fully. If this is the case the lifter should be replaced.

I think in general that the N52 engine does sound a tiny bit noisier at idle with the bonnet open than some other engines anyway. With the bonnet closed and the HVAs not in 'ticking' mode, you shouldn't really be able to hear anything other than a 'purr'.

I'd say - go with your gut feeling.

Good luck! :)
 
Hi, my 2006 Z4C did this just once after the winter lay up when I started and stopped the engine two or three times while moving it around without getting the engine warm. It cleared very quickly on the road and has not done it since, however there are people on this forum with experiences which have needed great expence to rectify. Tread carefully!
Not sure wether it is relevant or makes any difference but 43,00kms is nearer 27,000 miles.
 
Also, as we're not sure on the exact noise you are hearing and thus diagnosis and advice is difficult, this is a good video to hear two noises that your engine might be making http://www.youtube.com/watch?v=5jz7ZQWMSwo . We're assuming you're hearing HVA noise but it's not the only noise these engines make.

The 'whirry' noise in the video is probably the injectors - some engine's injectors sound noisier than others. You can hear my injectors quite loud with the bonnet up, but can't really hear them when it's down. In my 11 years of car ownership, I'd say my 3.0si engine's injectors are the noisiest of any of the 20+ cars I've owned, but don't give me any cause for concern. I can only hear them at idle with bonnet up stood next to the engine. Can never hear them from inside the car. Of course, this noise is heard whenever your engine is running.

The other noise is a knocking noise and is the lifters (HVAs). Here is some information about several potential causes, along with some easy cures, of HVA noise http://www.enginebuildermag.com/Article/48377/toubleshooting_bmw_hydraulic_bucket_tappet_problems.aspx
 
The best way to reassure yourself this is a normal N52 sound would be to test drive another one or two cars. The HVA issue don't come back when the car is warm, so unless the damage has already been done I guessing it's normal noises you are hearing.
 
wow, thanks for the help guys!

mediabrand - the engine sounded like the one in your video, but without the louder noise that seems to be tapping at about 5 times per second - although I did hear the loud noise for that split second on start-up.

srhutch - thanks, I'm going to have a look at another one today, will let you know how I go.
 
cooots said:
mediabrand - the engine sounded like the one in your video, but without the louder noise that seems to be tapping at about 5 times per second - although I did hear the loud noise for that split second on start-up.
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If that's the case, I would say you probably heard a few seconds of HVA noise when you first started the car which is perhaps understandable if the car had been sat for some time. At least it cleared itself quickly. srhutch is totally right about comparing the noise of running 3.0si engines in other cars. Then you will reassure yourself what is 'normal'. Go back to the original car, start it up from cold and see what happens again. See if the dealer will allow you an extended test drive, which will give you chance to scrutinise the car away from their prying eyes. That's what the dealer where I bought my car from did for me, and I felt like I had more time to poke around and see what was what without feeling the pressure of a salesman stood next to me :D

By the way, in terms of noises you might hear, this video is what a noisy Vanos unit sounds like (wrong engine but noise would be similar). Would sound like a diesel! This is a 'before and after' video which allows you to hear the difference after a repair has been effected http://www.youtube.com/watch?v=hUNYvwn9ivw

DPG said:
Does this cause damage to the engine or is it just the noise?
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I don't believe that noisy lifters cause damage to other parts of the valvetrain, but I would assume that any part that isn't fully lubricated at all times will wear at a faster rate. If you start to hear HVA noise all the time it could be a sign of a damaged / worn lifter. Lifters can be replaced but I've heard it's quite costly. Several posts around the internet state that BMW say the sound is harmless, but I personally think any ticking noise is an indicator of some kind of wear, no matter how minor.

What BMW probably mean is that over the normal expected lifetime of the engine, the lifter wear created during 'ticking' condition is not significant enough to cause failure. Just a guess as to why they say it's not a problem.
 
I would say it would cause damage as the camshaft and lifters will loose contact and when they contact again it is like a hammer.

How long for this damage to show would depend on a number of factors, like how often does it happen and for how long.

What I can confirm is that after having my head changed my car no longer suffers with this problem even if it's been standing for a month or so.
 
Apologies if this is easily found out elsewhere but from what year was the improved cylinder head fitted on the N52 engine?
 
Taz x said:
i have a very late Z4, first registered 31-3-2009, i have had this problem once
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Could have been built in 2008 quite easily. Mine was built 4 months before being registered.
 
Well, I went and saw another 3.0si coupe the day after to compare.

It pretty much sounded the same - a consistently quick tapping noise, but nothing too loud. I guess it could just be me being a little over-cautious, or just used to the quieter motor in my Holden.

mediabrand - thanks for posting the video. I must say tho, the N52s I've seen sound more tappy than the diesel does after the vanos was fixed - (but I don't think the tapping I'm referring to would get picked up in a video).

I guess BMW would be able to tell me pretty quickly if it was an issue if I got them to do a pre-purchase inspection for me.
 
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