Whirring/fan noise on start up
Whirring/fan noise on start up
I've trawled through the various posts, but can't quite find one that matches my query on start up.
I have a '97 Z3 2.8 (M52). On start up it roars into life, but is accompanied by a very loud whirring sound like a fan noise. After a couple of minutes running it seems to stop, and when I pull up its gone. We reckon it's the viscous fan but not really sure. Any ideas on this, or is it just a 2.8 (52)thing? May be something else
I have a '97 Z3 2.8 (M52). On start up it roars into life, but is accompanied by a very loud whirring sound like a fan noise. After a couple of minutes running it seems to stop, and when I pull up its gone. We reckon it's the viscous fan but not really sure. Any ideas on this, or is it just a 2.8 (52)thing? May be something else
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
It could be the secondary air pump... its located on the left of the engine at the front as you look under the bonnet.
It pumps air into the exhaust on start up to reduce emissions. This was a requirement for the American market.
It is unnecessary in the UK and you can disconnect it providing you blank off the exhaust connection..
see here:
http://www.zroadster.net/forum/viewtopi ... +secondary
It pumps air into the exhaust on start up to reduce emissions. This was a requirement for the American market.
It is unnecessary in the UK and you can disconnect it providing you blank off the exhaust connection..
see here:
http://www.zroadster.net/forum/viewtopi ... +secondary
Last edited by gookah on Sun 08 Jun, 2014 11:59, edited 1 time in total.
Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)
I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
Re: Whirring/fan noise on start up
Thanks gookah for the info. Looking back through the various posts I'll carry out the various tests, but if the sec air pump is not required, then perhaps I'll treat it like an appendix...and take it out! Matter of interest, when the car was new back in '97, would the pump have been quieter and just got noisy with age??
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
-
- Joined: Mon 28 Oct, 2013 19:35
- Posts: 261
Re: Whirring/fan noise on start up
As someone once remarked . . . "is that the hairdryer I can hear?" BB
Re: Whirring/fan noise on start up
Rocky Dave does smirk somewhat whenever I drive past his abode! Very embarressing
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
Will be interesting checking out the theory about it being the "air pump"...
But to my "untrained ears it does sound like the viscous fan running. Looks like a bit more research needed
But to my "untrained ears it does sound like the viscous fan running. Looks like a bit more research needed
Re: Whirring/fan noise on start up
Hi Koolflyer I had/have the exact same problem on my 2000 yr 2.0 Auto. It is the " smog pump " as they refer to it in the US. I have tried to lubricate the bearings in the motor of the pump to no avail. There is a video on YouTube which shows how to strip the motor and cure the fault. Cheers, Tony.
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Ps the pump is run through a relay to switch off after so long after start up.
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Ok, thanks for that t-tony. I'll check utube out, and also when this blasted weather improves I will have the bonnet up and have a good listen. Appreciate your comments.
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
No worries mate, the guy on you tube takes the motor apart by drilling out the rivets and when he puts it back together he replaces the rivets with small nuts and bolts. I plan to do mine this next weekend as the wife is away in Florida for a week or so. I'll let you know how it goes.
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Mine is fine touchwood but I am aware that this can become an issue, does someone supply / make the necessary blanking plate / gasket?It is unnecessary in the UK and you can disconnect it providing you blank off the exhaust connection
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
Re: Whirring/fan noise on start up
Very interested to see how you get on t-tony
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
Hi Alan if I end up making one for mine I will make you one too. It's not difficult I had to make one for a Mondeo TD ST at work the other week.
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Oh wow. thanks mate!
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
Re: Whirring/fan noise on start up
t-tony, Florida or head under the bonnet......just wondering who drew the short straw?!
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
I could tell you. . . . . . but then I'd have to kill you.lol
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Ha!
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
Ok, got a bit of free time, opened the lid and it would appear that my 'Z' is not fitted with a secondary air pump "smog pump", but have a nice plastic water bottle instead...umm. Perhaps it is the viscous fan after all?? At least I'll have a nice clean windscreen
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
According to OEM your 2.8 should be fitted with an air pump it would be buried at the front passenger side of engine bay, opposite side to your plastic bottle and under the filter housing.
Colb
Colb
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
Re: Whirring/fan noise on start up
This is the layout under the bonnet of my 2.8 where you can see the washer bottle towards the back right of image and the smog pump front left of image (where your washer bottle is). This could be because my engine is the M52TU Twin Vanos unit and yours is the single Vanos one?
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
Re: Whirring/fan noise on start up
The layout of your car is the same as mine Alan. As I said if I end up making a blank for mine I will make you one. Not too sure about Koolflyer's but whatever shape if needs be....
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Thanks Tony
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
Re: Whirring/fan noise on start up
Mine is an M52 which I'm sure is a single vanos engine, unlike the M52TU (technical update) which is a double vanos unit. This is maybe the reason why mine doesn't have the sec. air pump fitted front left (if at all), although I will check front right under the filter housing as suggested.
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
Ok, the rain has stopped and back to my original post. Just to recap, it's been suggested that the whirring noise is coming from from the secondary air pump/smog pump on my M52 2.8, but when you look at my M52 there appears to be no pump in the usual place (front OS) just the washer bottle. It has also been said that according to the OEM drawing it is located on the front NS. I have had a good look there too and its not there. It consists of a large circular black plastic covered item along with a smaller silver topped circular item which bolted onto the exhaust manifold, (this I assume is where the blanking plate that has made made by some fits if the secondary air pump is removed). Compare the M52TU Twin Vanos of Alan W to my M52 Single Vanos. I can only think that not all engines were fitted with a secondary air pump, or perhaps the straight M52's weren't fitted with them?? Next time you have the lid up, have a look because we'd certainly be intersted.
Which brings me back to the original question, if it's not the secondary air pump (perhaps because there ain't one? ), then what is the noise?
Which brings me back to the original question, if it's not the secondary air pump (perhaps because there ain't one? ), then what is the noise?
Re: Whirring/fan noise on start up
Not all car had the secondary air pump, as far as I can work out these were fitted to help reduce emissions, I have seen them both on m52 and m54 engines.
Could the noise be your viscous fan?
Could the noise be your viscous fan?
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Whirring/fan noise on start up
Q. Does the sound originate when the ignition is turned on ? ie. prior to firing the motor... Or, is it apparent only once the motor is running ?
Re: Whirring/fan noise on start up
Thought that might be the case, as I have looked into so many engines now and it appears some do and some don't have a pump fitted. Just turned the ignition on without firing up and its as quiet as a mouse, however when fired up the fan is whirring away, but the noise dies down or stops when she is warmed up.
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Whirring/fan noise on start up
You can easily check if the culprit is the viscous fan....Get a rolled up newspaper and start the motor...use the newspaper to stop the viscous fan from turning...if the whirring also stops...you have isolated the cause...
Re: Whirring/fan noise on start up
Ok, I've proved that my Z doesn't like the Daily Mail! I couldn't stop the fan with the paper, it just munched it and kept going. Should you be able to stop it then, and what does this mean?
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Whirring/fan noise on start up
.... hahahaha....it proves that the viscous fan is working...also, that it is likely to be the viscous fan making the noise...You should be able to stop the fan, and therefor the viscous clutch you have is likely not OEM... There are aftrmarket viscous clutches which don't "release" as soon as the OEM ones do, and the result is the fan is spinning as fast as the motor. This can be heard quite loudly until the fan clutch warms up and "releases" somewhat.
Re: Whirring/fan noise on start up
With the engine tuned off and cool you should be able to spin the fan freely by hand. If not then the viscous coupling is shot.
Re: Whirring/fan noise on start up
Engine off, you can turn the fan, although there is a small amount of resistance....?
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
Basic operation of the viscous coupling is that is should freewheel when cold and the fan will be dragged round slowly. When hot the coupling locks and the fan rotates in proportion to engine speed. A rolled up newspaper should stop the fan when cold.
Note however that some zeds have electric fans and some have additional fans in front of the radiator for aircon.
Cheers R.
Sent from my GT-I9300 using Tapatalk
Note however that some zeds have electric fans and some have additional fans in front of the radiator for aircon.
Cheers R.
Sent from my GT-I9300 using Tapatalk
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Re: Whirring/fan noise on start up
Righty, I do know that the viscous fan did have some work done to it when I bought it in Devon, perhaps its a non OEM job then?? Interestingly, when its warm, (1) the noise goes and (2) the fan is still turning but not fast, like it's on tick over revs, which I assume is what should be happening. It's just this initial start up phase...say 3-5 mins approx. whilst the temps come up. Perhaps I'll give the Socialist Worker newspaper a try, God knows what it'll do to that!
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
why is the blanking plate necessary when disconnecting the secondary air pump I just unplugged the electrical connector and the noise stopped that was 4 years ago and nothing bad has happened
Re: Whirring/fan noise on start up
Quick explanation of the secondary/emission control air pump.
The pump sucks in fresh air through the hose #6 and blows it into the exhaust through hose #5.
Access to the exhaust is controlled by a vacuum operated valve #1 (also visible above). This is normally closed, except for when the pump is operating. The vacuum supply is controlled by a smaller electrically operated valve #5.
If you just disconnect the power supply to the pump, then when the pump would normally be being run, hot exhaust gases will make their way out through the vacuum valve and not down the exhaust, leading to strange exhaust noises, melted hoses, corrosion of the pump etc. etc. Assuming that the electrically operated valve is normally closed, then disconnecting that as well should be safe, however is has been know for one or the other of the valves to fail and we have seen pictures of melted hoses posted on here.
If you want to remove the complete pump, fitting a blanking plate to the exhaust in place of the vacuum valve will ensure that the exhaust gases will follow the correct path.
Cheers R.
The pump sucks in fresh air through the hose #6 and blows it into the exhaust through hose #5.
Access to the exhaust is controlled by a vacuum operated valve #1 (also visible above). This is normally closed, except for when the pump is operating. The vacuum supply is controlled by a smaller electrically operated valve #5.
If you just disconnect the power supply to the pump, then when the pump would normally be being run, hot exhaust gases will make their way out through the vacuum valve and not down the exhaust, leading to strange exhaust noises, melted hoses, corrosion of the pump etc. etc. Assuming that the electrically operated valve is normally closed, then disconnecting that as well should be safe, however is has been know for one or the other of the valves to fail and we have seen pictures of melted hoses posted on here.
If you want to remove the complete pump, fitting a blanking plate to the exhaust in place of the vacuum valve will ensure that the exhaust gases will follow the correct path.
Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Re: Whirring/fan noise on start up
thanks ill look into this
Re: Whirring/fan noise on start up
......so I wonder why the fan is at full chat on start up when the engine is cold, surely cooling from the fan is rarely needed at this stage?
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
Re: Whirring/fan noise on start up
It's no so much about cooling as getting clean air into the engine to reduce emissions. Also it only runs for a short time limited by the car's ecu's.
Bye the way, I started stripping the smog pump off my car and as far as I've got I found the bearings are very noisy. I will locate some replacement bearings and rebuild it just to see if it has got rid of the whirring noise. I'm confident it will.
Bye the way, I started stripping the smog pump off my car and as far as I've got I found the bearings are very noisy. I will locate some replacement bearings and rebuild it just to see if it has got rid of the whirring noise. I'm confident it will.
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
Like Beerbelly, I un plugged the pump motor to stop the racket and have had no ill effects but I think that if you disconnected the vacc pipe to the valve it couldn't open anyway. I'm not convinced that this small electric motor would be enough to overcome the pressure of hot exhaust gasses to blow them back into the engine?
"Knowledge and experience are not always the same"
Re: Whirring/fan noise on start up
I work in the motor trade and have a good contact who owns an independent bmw service centre ill ring him today and see what he says
Re: Whirring/fan noise on start up
We seem to have a few slightly different questions running here from the original post, all of interest. However, thanks to your help, I have now been able to establish that it would appear that my particular car was/is not fitted with a sec air pump/smog pump. The whirring noise is coming from the viscous fan and would appear that the viscous coupling is not working as it should. I again just started the motor and tried to stop the fan (this time with the Sun ) and the fan could not be stopped. However, after a quick warm up run the fan was just free wheeling and no associated noise either, and the Sun stopped the fan immediately (or page two did ). This is working contrary to Robert's quote above, which to me makes sense. I can only assume its got a 'duff' coupling, perhaps non OEM perhaps not, therefore would you guys agree that it needs to replaced.......things not working as they should is not an option in my book.Robert T wrote:Basic operation of the viscous coupling is that is should freewheel when cold and the fan will be dragged round slowly. When hot the coupling locks and the fan rotates in proportion to engine speed. A rolled up newspaper should stop the fan when cold.
Note however that some zeds have electric fans and some have additional fans in front of the radiator for aircon.
Cheers R.
Sent from my GT-I9300 using Tapatalk
Thanks again for all your valued input, that's what makes this such a brilliant forum
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
-
- Joined: Sat 29 Jan, 2011 20:34
- Posts: 361
- Location: tamworth
Re: Whirring/fan noise on start up
Just for info I changed my viscous coupling as the BMW one developed play and I bought one from eurocarparts. This also whirs like yours for the first few hundred metres then stops and behaves like the BMW one. Considering it cost less than half of an oem part I can live with that
Re: Whirring/fan noise on start up
Took mine off recently as I overhauled my whole cooling system. It should definitely behave as Robert T described above. I'm sure I still had (and still have) the OE one on my 1998 1.9 (85,000 miles) and it was imprinted with "Sachs" as the manufacturer - if that is any help to you in seeking a similar replacement.
Re: Whirring/fan noise on start up
Re Euro Car Parts - The best isn't always the cheapest. This through personal experience. Every day of the week!
"Knowledge and experience are not always the same"
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Whirring/fan noise on start up
Oddly, the start-up whirring is normal. The viscous fan is just that...filled with a viscous substance which is controlled by a temperature sensitive expanding spring. Also being "viscous" it will settle due to gravity into it's reservoir, and upon start-up will need to be re-distributed by the spin.
However, as Rob explained, this "viscosity" is increased (via a valve) with an increase in engine temperature. This is mostly correct. The viscous fluid is actually "thicker" when cold. As it heats up, it "thins" and can flow via a valve controlled by the heat sensitive spring. This allows the clutch pressure to increase and engage and or disengage the clutch as required.
The methodology is that by increasing the "viscosity pressure" at higher temps, the fan will only operate whilst the car is stationary - as at a traffic light or excessively hot - once the engine revs increase and whilst driving, the fan barely moves as the airflow in the forward moving car is sufficient to maintain cooling.
It would seem your fan is functioning correctly, albeit noisily. The newspaper test will fail if you leave the car standing and allow the motor to heat up above the "normal" operational setting of the viscous clutch. ie. the fan clutch will engage fully in an attempt to increase the airflow through the radiator.
http://en.wikipedia.org/wiki/Fan_clutch
However, as Rob explained, this "viscosity" is increased (via a valve) with an increase in engine temperature. This is mostly correct. The viscous fluid is actually "thicker" when cold. As it heats up, it "thins" and can flow via a valve controlled by the heat sensitive spring. This allows the clutch pressure to increase and engage and or disengage the clutch as required.
The methodology is that by increasing the "viscosity pressure" at higher temps, the fan will only operate whilst the car is stationary - as at a traffic light or excessively hot - once the engine revs increase and whilst driving, the fan barely moves as the airflow in the forward moving car is sufficient to maintain cooling.
It would seem your fan is functioning correctly, albeit noisily. The newspaper test will fail if you leave the car standing and allow the motor to heat up above the "normal" operational setting of the viscous clutch. ie. the fan clutch will engage fully in an attempt to increase the airflow through the radiator.
http://en.wikipedia.org/wiki/Fan_clutch
Re: Whirring/fan noise on start up
Just to pick up and put this thread to bed. In this case it wasn't the secondary air pump as my particular motor doesn't have one fitted, as you can see from under the lid photo. There was a lot of resistance from the viscous coupling when cold compared to another Zed I checked. It turned out to be a cheap unit...can't see the name, fitted last June new. It would appear nothing wrong with it but just tighter than an OEM or better quality unit. I now have a Sachs unit recommended and fitted by Barry Dead man (ex Sytner Leics) £120 fitted and no more whirring fan noise!
Technically, to the best of my knowledge there is actually nothing wrong with it apart from being a cheaper product. Its only done 2000 miles, so perhaps someone else could find a use......after all it does the job its supposed to. I'll put it on eBay if no onewants it......offers for a few beers perhaps??
KF
Technically, to the best of my knowledge there is actually nothing wrong with it apart from being a cheaper product. Its only done 2000 miles, so perhaps someone else could find a use......after all it does the job its supposed to. I'll put it on eBay if no onewants it......offers for a few beers perhaps??
KF
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
- Southernboy
- Joined: Thu 07 Oct, 2010 12:39
- Posts: 6437
- Location: Johannesburg
Re: Whirring/fan noise on start up
.... I went through the same process a few years back... cheap viscous coupling which made such a noise.... it didn't release at higher revs either... so the car sounded like a 747 in takeoff mode...