BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read

Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Mechanical Maintenance: Break-in / Oil & Fluids / Servicing
Steve Thomas BMW
Post Reply
Thread Tools Search this Thread
      08-28-2012, 02:25 AM   #1
First Lieutenant
Drives: A4 quattro 3.2 MT6; E92 6MT
Join Date: Mar 2012
Location: Boston

Posts: 310
iTrader: (0)

Small fluid leak on hot days

I've noticed a hissing sound, after I get out of the car on hot days. Some kind of fluid is dripping on something very hot, though only a few drops and I haven't been able to pinpoint the source of the sound. It sounds like big drops and they only sizzle for a second.

I also have had the impression I smelled antifreeze (not then, but other times), but that could just be me.

Anyway, is there any chance it's something trivial, like condensation from the air conditioning? Or is it definitely something bad?

If it were tranny fluid or power steering fluid, would it have a distinctive odor (like burning oil)? I didn't really smell anything unusual, at the time.

BTW, when I say "hot days", I mean by New England standards. Like mid 80's or 90's. I know some of you will scoff at that, but it's also humid, FWIW.
Drifty// is offline   United_States
Appreciate 0
Reply With Quote
      08-28-2012, 07:15 AM   #2
M3 Lover
elm3's Avatar
Drives: 2009 e92 M3 Interlagos Blue
Join Date: Sep 2008
Location: Canton, GA.

Posts: 1,863
iTrader: (1)

Garage List
This is just water from condensation coming from the A/C unit hitting the hot exhaust. Perfectly normal.
'09 E92 ///M3 Interlagos Blue, 6MT, Silver Novillo Leather, CF Trim, Premium Package, Technology Package, Cold Weather Package, Premium Sound, 19" Wheels, Moonroof-Toy/ '14 335i, Sport Line, Premium Package, Technology Package, 19" wheels, Heated Seats - Daily Driver/ '04 Yamaha R1 - Toy/ '06 Yamaha Raptor 350-Toy
elm3 is offline   United_States
Appreciate 0
Reply With Quote
      08-28-2012, 01:33 PM   #3
M3PO's Avatar
Drives: '08 IB E92
Join Date: Sep 2011
Location: OC

Posts: 2,749
iTrader: (7)

If you smell anti-freeze, it may be that the coolant system is overfilled and the overflow bottle is overflowing on particularly hot days (when coolant temps are the highest and the coolant expands the most).

I've never heard a hissing sound after using my AC.
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R
M3PO is offline  
Appreciate 0
Reply With Quote
      08-28-2012, 01:47 PM   #4
BimmerPost Supporting Vendor

THE TECH's Avatar
Drives: BPMsport 2012 E92 M3
Join Date: Jun 2011
Location: Kansas

Posts: 13,111
iTrader: (45)

Garage List
Send a message via AIM to THE TECH Send a message via Skype™ to THE TECH
Keep an eye on the coolant level and see if it's changing.
THE TECH is offline   United_States
Appreciate 0
Reply With Quote
      08-28-2012, 02:25 PM   #5
BMW Fanatic
Drives: slow
Join Date: Jul 2009
Location: Calgary

Posts: 3,314
iTrader: (11)

AC. As an excuse to drive your car; turn it on, AC off, drive for 30 minutes, park up, no hissing sound. Problem solved.
BMW Fanatic is offline   Canada
Appreciate 0
Reply With Quote
Post Reply


fluid, hiss, hot, leak, sizzling

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -5. The time now is 05:39 AM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.,,,,,,,,, logo and trademark are properties of BIMMERPOST