HVAs

D

Dewi

Active member
 A tripe shop doorway somewhere in Lancashire
I've been reading about the HVA problem on the N52 engines whilst looking up a few facts for my forthcoming purchase of a Z4. (hopefully going to see a couple more this weekend) Quite a big thing was made of it a few years back by a few folks on here, but from what I can see there's not been much mentioned about it for a while now (I am crap at using forum searches though) . It seemed to be an issue that affected more US cars than UK ones for some reason.

Was it a storm in a tea cup? Is it as bad an issue as some would have us believe, and were all versions of the engine affected or was it more prevalent in one capacity than the others?

It's not actually putting me off buying a Z4 as most cars with hydraulic valve lifters will be a bit tappety when cold. My old Mk1 MX5 was always very tappety when starting from cold, but is it a big problem on the BMWs, and how widespread is it?
 
I couldn't tell you how wide spread it is, but the first Z4C I went to see (38,000 and immaculate) had it really badly. It was like a coin being tapped under the bonnet. The car had only ever been used for short journeys, and even after a good warm up, then a bit of a blast the noise was still there and very loud.

If it's stuck, walk away.

The owner just said it was normal. I got my Z4C (57,000) and the engine sound was night and day. A bit of injector noise, but nothing like the HVA issue. You will definitely be able to tell.

I went for a lower spec'd car, rather than chance it. If the HVA is stuck, it would be like having a very loose tappet. Or at least that's what my meagre knowledge of mechanics would indicate to me.
 
No doubt you have seen my thread.

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

There is no pattern to this happening, but as above I would walk away from any car exhibiting this for more than a few seconds. If best case scenario it doesn't do any damage (which I don't believe) think what the next buyer will think when you come to sell and it sounds like a Trabant.
 
Yes, I saw that thread which is what alerted me to the problem in the first place, but it just kind of fizzled out. Interesting that some cars have it and others don't? Begs the questions: is it the way the car is used or is it the way they've been serviced and maintained. Given that there must be some kind of quality control at the manufacturing stage and all cars leave the factory within some kind of tolerance, the assumption has to be that the cause is due to the type of use or the level of maintenance.

Not much mention has been made on this forum for some time
 
Had my car from 70 mikes. I drove it how you are meant to drive it, and maintained it by the book by my local main dealer 1/2 mile away. That was one reason it was easier to resolve as they were so close. Bottom line is it was a design fault. Other factors may play a part, such as in my case being used every other day so more time for the oil to drain back. Other cars maybe due to short journeys, no pattern was ever determined.

As you say the problem hasn't been seen for a while so either we were the unlucky few or owners are putting up with it or if it was going to happen it would have by now. You are aware of the issue, so at least you can make an informed decision when you find something you like.
 
Yes, I have that advantage of knowing that a probelm exists. The car I went to look at yesterday was a bit suspect because when I turned up at the garage he'd "popped out" in the car. Bearing in mind that it is his own personal car and not one from the business (it has his own personal plate on it so that bit's true) it could well be totally innocent. I did like the car though so I may pop back over the weekend and ask him to leave it stone cold for when I arrive. There were no untoward noises from the engine when it was hot, in fact it sounded rather sweet.

As far as being a design fault goes, given that some cars suffer and some don't, I'd prefer to think there are manufacturing tolerance issues at play. If it was a generic design fault surely every car would display the noisy HVA symptoms? There are so many variables that without a proper scientific study everything is pure conjecture so we'll probably never know. :)

Edit: I did go to look at another car on Tuesday at a dealers. It had obviously been stood for a good while on the forecourt and probably only ever been started up in all that time to shift it from one place to another, but when I started it up it was relatively quiet.
 
I have had the HVA noise twice. It only happened when I had done a number of short journeys over a few days and the engine had never got up to full operating temperature. There was no drop in performance or economy and after a proper run it went away. Haven't had the problem at all since then and that was over a year ago and there is nothing wrong with my engine. Obviously I wouldn't have bought a car with an engine sounding like that but if it happens and you've done lots of little journeys over a few days it doesn't mean the engine is shot either.
 
Zeld4 said:
I have had the HVA noise twice. It only happened when I had done a number of short journeys over a few days and the engine had never got up to full operating temperature. There was no drop in performance or economy and after a proper run it went away. Haven't had the problem at all since then and that was over a year ago and there is nothing wrong with my engine. Obviously I wouldn't have bought a car with an engine sounding like that but if it happens and you've done lots of little journeys over a few days it doesn't mean the engine is shot either.
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If you get it once or twice like you have it would not worry me either.
 
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