Funky engine sounds? Paranoia? Help? :)

[TiAg ///M3/4]

Heya folks! I've had my '98 ///M3/4 (5-speed, 42000 miles) for about three weeks now, and I'm starting to notice a few fairly subtle sounds that have me concerned or curious.

Key background: Vehicle was purchased as CPO from a local dealer. Seems to
be in pretty good condition overall. Doesn't even burn oil (except for any
oil overfill, which got dusted pretty quickly ... it's stayed constant at
the high fill mark since; and I doublechecked this last night) which has
been pleasant.

Also, this is my first manual transmission car (though I've been driving for
over ten years), so I've been hyperfocused on shifting and such, and have
only recently gotten comfortable enough with this to even be capable of
detecting these, so it's completely possible that these are normal and I'm
just being new-owner-paranoid.

I've done some searching of various message board archives and such, but
since many of these symptoms are described quite subjectively (by me as
well, of course), it's tough to come up with ideas outside of a dialogue. If
any of you can provide any insight into any of these, I'd be extremely
grateful! Here goes:

1) Idling in neutral at startup, there seems to be a sound like, um, a paint
thinner can being slightly dented in at regular three-second intervals. It's
usually chilly for the area (50-55 degrees F, I love CA) at these times.
Seems to come from the forward area, or almost in the cabin. (Haven't had
the time to isolate it more.)

2) On the move, in all gears, there's a soft whisper/hiss that sounds like
wind noise, though it varies with RPMs rather than speed. Today, it seems
that this sound gets a little more aggressive/rough sometimes, possibly as engine temperature
increases. Makes me think of belt issues for some reason, though those are
usually described as a squealing kind of sound, and I don't know how the engine temp would affect that. [Yep, grasping-at-straws time ...]

3) Perhaps this is another manifestation of #2, but there is sometimes a
different whistle when changing application of throttle, which seems to go
away when the accelerator's in a steady state. This is definitely new for me
-- just noticed it this morning.

4) I have this huge grin I can't seem to get rid of. Man, I love this car.

#2 and 3 have me more concerned than #1. The fan belt seems pretty new,
though I'm no expert on these matters ... so I'm wondering if all the belts
were replaced as part of the CPO process or Inspection 2 (performed in April
of this year) and that they may be wearing a little. From the archive
searches, some folks mentioned using WD-40 as a temporary mask of various
belt sounds (though not a solution!) that would wear off quite soon. It
makes me wonder if these issues existed before I purchased the car, but the
dealer took the WD-40 route to save some cash, and now it's wearing off.

Again, if any of you have any ideas, I'd really appreciate it! I'm not too
knowledgeable about engines, so please be gentle. Thanks!

[Jim O.]

For #2 and #3 - are these noises coming from the front or the back? Try removing the rear seat bottom and going for a test drive - does the noise get louder? Are you using the stock airbox, and does it have both baffles in place?

Jim

[TiAg ///M3/4]

Thanks, Jim! 2 and 3 both seem to be coming from the front, in the engine bay. Everything on the vehicle is stock as far as I know. I'll crack open the ol' Bentley and see if I can give those airbox baffles a check!

A suggestion elsewhere for #1 was that it was the cat warming up or climate control calibrating. But again, I'm not as concerned about that one, barring other advice.

Another suggestion for 2/3 was the AC compressor & its clutch. I tried driving for a while with the CC off, with no change, but I don't know if that'll affect anything.

Tonight's going to be a good Bentley night.

[Bill]

what wait oil is in your car?

[JatZilla]

You can isolate any wind noise by doing this: Start the car, turn on the fan HIGH, get out of the car, put a vaccuum extension pipe to your ear. Slowly move around the car, pointing the other end of the pipe on areas where door meets frame, glass meets metal etc. If there's someplace where the seal isn't so tight, you'll hear it.

I would suggest you get used to the car some more. Most M3s have this whiny/whistle pitch to the engine, that changes with RPM. Leave the belts alone, don't spray anything on them at all. If the belts have never been changed and you have a '98, you may want to change them now. $15 + $9 for both belts, from bimmerparts.com. Took me 3 hours to change mine but I also changed the thermostat and water pump.

[TiAg ///M3/4]

Bill: I don't know, since it's what they changed into it pre-purchase. I'm presuming it's the BMW blend of Castrol 5W30 (?). Only about 1000 miles on this batch, which was clean and full. Got 8 quarts of Mobil 1 5W30 (gotta have a spare!) and a few filters in the trunk to do an early change this weekend, just in case and for the hell of it. (I've been a busy monkey!)

[umnitza]

big time congrats on your purchase...
I was in exactly the same boat as you.
I too had driven a few cars with sticks, but this was the first "sports car" with a stick.

The grin will only grow wider with time...be careful...you'll find that you stop thinking about work and want to go for a drive for the heck of it.

Also, plan on inceasing the threshold of your capabilities with this car VERY slowly...you'll learn more about the car. Don't try the fast sweepers very quickly just yet.

As for the noises, I wouldn't worry about them that much...but if you want...take it to a very professional shop like Dinan (I think they're good...but I don't have personal experience...just people I know that have gone). Have them do a quick inspection, the money spent will alleviate your fears.

As for the CPO part, if anything happens...be forceful with the dealer if anything happens...I mean ANYTHING.

Also, you need to have EVERYTHING changed now while the car is still completely under the original warranty. I had the steering wheel, new tires, new pads, new shifter all replaced as part of the CPO when I complained. I should have complained about the seats as well...but it was too late ( I had 51K miles by then)...I bought mine with 45K on the odo...and it was a Florida car.

[TiAg ///M3/4]

JatZilla: Great tip, thanks! One for the little homegrown tip file.

I think your second paragraph is the bottom line -- I don't know the car nearly well enough to get freaked about possible phantom sounds. Some replies I've received elsewhere corroborate the idea that the whine is normal. Heh. I kinda like it anyway.

I'm thinking my best course of action is to just casually mention it to the boys at the shops I'm thinking about using down here and seeing what they think when I swing by in a few weeks. I'm going to have 'em do a little inspection for all the stuff I can get done by the dealer while it's still under the factory warranty ... but I'll cancel panic and just do the belts myself.

(Strategy: Build a relationship with a shop before I'm up the creek with a big prob!)


Thanks for the advice!

[TiAg ///M3/4]

umnitza: Love the .sig! And thanks for the advice as well. I'm taking it pretty
easy so far ... it's easy to tell that this beast is a lot more capable than I am. Mod number one: DRIVING SCHOOL. Oh, and my daily commute (Hwy 17 over the Santa Cruz Mountains) is obviously a huge cash cow for the CHP, so, well, yeah.

Roger the CPO tip. Hardcore mode on.

I love my E30 325is, but it's so good to be in this family now. Thanks for the welcome.

[Jim O.]

2 and 3 may be the fuel pump making its normal amount of noise - the reason I suggested removing the back seat is that the fuel pump is right under the seat. If the noise that you're hearing gets a lot louder, then that's probably it.

Or, it could be normal intake noise. Or even alternator noise (if you turn off the radio, can you still hear the noise?).

Your best bet is to take it to a good shop, and have them inspect the car. Or, get another M3 driver to listen to the noise, and see if it's normal.

Oh, by the way, the Golden Gate Chapter of the BMW CCA is having an autox down in Marina this Saturday - if you want to start learning what your car can do, this is an ideal opportunity. For more information, see the web site at http://www.ggc-bmw-cca.org .

Jim

[umnitza]

Originally posted by TiAg ///M3/4
umnitza: Love the .sig! And thanks for the advice as well. I'm taking it pretty
easy so far ... it's easy to tell that this beast is a lot more capable than I am. Mod number one: DRIVING SCHOOL. Oh, and my daily commute (Hwy 17 over the Santa Cruz Mountains) is obviously a huge cash cow for the CHP, so, well, yeah.

Roger the CPO tip. Hardcore mode on.

I love my E30 325is, but it's so good to be in this family now. Thanks for the welcome.

stay on this board and we'll trade stories...I think our cars are roughly the same...what color and options break down is yours?

[TiAg ///M3/4]

Jim: Sounds good, thanks man. I'm going to try to make it to the autox (Joe D. from Suzy's list also gave me a heads-up) ... might be getting there late though, so perhaps I'll just spectate and drool.

[TiAg ///M3/4]

umnitza: Sweet. The East Bay family doesn't get off easy in terms of CHP coverage, either. Those of us on the Hill, however, do get some interesting times when it's raining and semis want to move into your lane. Glad I knew my E30 pretty well ...

Um, vehicle options: 98 M3/4, Titanium Silver on Black. Full OBC, split folding rear seats (score!), power front seats (bahhh), H/K, a few other goodies and a 100% boost in probability of "sure, guys, I'll drive." What about you?

[99M3]

TiAg///M3/4: I experience #1 as well.

Did you figure out what was it, and how to get it fix ?
Bringing up an old thread here :-)

[TiAg ///M3/4]

Nah, nothing yet. Think it's just funny bits getting warmed up or something. I rarely notice it anymore.