e34 knocking noise from engine - BMW Forum

d3ity · 07-11-2004, 03:02 PM

Hey all, i have a strange knocking noise that seems to speed up as you rev the engine. It happens in all gears, it seems repetitive, almost like a belt, but is originating from under the shroud on the engine (From what i can tell) What could this be? A simple tune up issue? A serious engine problem?

LOS · 07-12-2004, 11:06 AM

This suggestion may sound dumb but did you check the oil level?? Any oils leaks?? Also, is it like a pinning sound?? This is caused by cheap gas...

LOS

d3ity · 07-12-2004, 02:29 PM

our mechanic checked the oil when it was in for inspection today, he said it was fine... its more of a knocking sound..

sp0rky · 07-12-2004, 09:33 PM

check your fan clutch... they make ODD noises....

EXtech · 07-12-2004, 10:13 PM

D3...by "shroud" do you mean around the fan shroud? I would look to the water pump. The a/c compressor can make a knocking sound when going bad, try turning the a/c off while the engine is running and see if that helps. Could also be a belt tensioner. Other possibilities range from rod knock, main knock, oil pump, rocker arm/shaft... is it very loud, more of a high-pitched knocked/rattle sound, deep knock felt throughout the car...? Can you give a little more detail? Like when it started happening and under what conditions like hard acceleration, upon startup etc.

silverlea · 07-12-2004, 10:56 PM

I had a similar situation and yes it was our old friend .....the water-pump.
Low octane fuel could cause detonation,which sound like your description.
Are you sure nothing is catching on the bottom of the radiator shroud.If your water-pump is stuffed,remember the fan runs on the same bearing,rite into the pump and it will be all wobbly cos the shaft the fan is mounted goes into that waterpump bearing..............therefore if the fan is not running true,it could well be catching the bottom of the shroud each revolution.
trust you get it sorted.
Good Luck.

SILVERLEA.

d3ity · 07-13-2004, 01:49 AM

By shroud, i was referring to the engine shroud. However, there are two cracks in the fan shroud. As soon as i see the car again, i will start to look at the fan clutch and see if that is the issue. It isnt the air conditioner, as i had it turned off and the knock persisted, its not really a knock you can feel, its just a sound as far as i can tell. Its a "light-moderate" knocking sound, not very high pitched, and not very low pitched. It also doesnt sound hollow at all. I cant tell you when it started happening, as i just got the car two days ago.

On another note, my mechanic told me today that my front end is "a mess", and i already need 1600 in repairs. He suggested a *gasp* dealer take a look at the car as far as the engine noise goes. I avoid my dealer like the plauge as a general rule.

BTW, sp0rky, where did you get that wood trim for your center console? (the part for the AC/Radio/computer). mine was mangled in a failed attempt to install a CD player properly, and the piece around my shifter needs replacing as well

sp0rky · 07-13-2004, 05:17 PM

It was a kit i got off of ebay... i think it was 119.00 and the fit was pretty good... but there were a few small issues with it. not bad for the price at all though.

About the fan clutch.. I know it sounds wierd, but mine makes this noise like a belt slipping sometimes.. at other times it sounds like its hitting my radiator or something.. its kind of crazy... its always making a wierd noise... just sharing my experience.

BTW: is this e34 your new one? the 95??

d3ity · 07-14-2004, 12:45 AM

Sp0rky, that dash looks sweet dude, i really like it. Im gonna try to get one ASAP.

Now i need more information on the repairs. Right now im praying for detonation. But i want to be prepared for any eventualities.

As far as the fan clutch goes, how hard is it to replace? is it something i could do in my driveway? I'm looking at this as an option for the replacement. http://www.bmwe34.net/E34main/Upgrad...trical_fan.htm

Is this a good option? It seems like a fairly simple install, are there any problems with this setup or has anyone had experience doing something like this before?

Next, i'd be looking at the water pump, It sounds like a more difficult project, what is involved? How hard is it? Is it practicable to DIY? What will be needed and how much will it cost me?

Also, I'd be interested in the oil pump. The thought of this worries me, as it sounds like a major undertaking, Once again, Difficulty? Practical? How much will it cost?

As far as the other repairs go, (rod knock, main knock, rocker arm/shaft) I really need more information on exactly what is involved. As of right now im unsure as to exactly what components these are involved in and what they do, they do not sound like cheap repairs however.