Small fluid leak on hot days

Drifty// · 08-28-2012, 02:25 AM

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.

elm3 · 08-28-2012, 07:15 AM

This is just water from condensation coming from the A/C unit hitting the hot exhaust. Perfectly normal.

M3PO · 08-28-2012, 01:33 PM

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.

THE TECH · 08-28-2012, 01:47 PM

Keep an eye on the coolant level and see if it's changing.

BMW Fanatic · 08-28-2012, 02:25 PM

AC. As an excuse to drive your car; turn it on, AC off, drive for 30 minutes, park up, no hissing sound. Problem solved.

08-28-2012, 02:25 AM	#1
Drifty// Second Lieutenant Drives: A4 quattro 3.2 MT6; E92 6MT Join Date: Mar 2012 Location: Boston Posts: 250 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. __________________
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08-28-2012, 07:15 AM	#2
elm3 M3 Lover Drives: 2009 e92 M3 Interlagos Blue Join Date: Sep 2008 Location: Canton, GA. Posts: 1,656 iTrader: (1) Garage List 2009 E92 M3 [5.00] 2002 Nissan Xterra ... [0.50] 2004 Yamaha R1 [0.00]	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//'02 Nissan Xterra- Daily Driver/ '04 Yamaha R1- Toy/'06Yamaha Raptor 350- Toy

08-28-2012, 01:33 PM	#3
M3PO Colonel Drives: '08 IB E92 Join Date: Sep 2011 Location: OC Posts: 2,176 iTrader: (6)	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

08-28-2012, 01:47 PM	#4
THE TECH BimmerPost Supporting Vendor Drives: BPMsport 2012 E92 M3 Join Date: Jun 2011 Location: Kansas Posts: 11,884 iTrader: (39)	Keep an eye on the coolant level and see if it's changing. __________________ Check us out on Facebook at BPMsportLabs

08-28-2012, 02:25 PM	#5
BMW Fanatic Colonel Drives: slow Join Date: Jul 2009 Location: Calgary Posts: 2,871 iTrader: (9)	AC. As an excuse to drive your car; turn it on, AC off, drive for 30 minutes, park up, no hissing sound. Problem solved. __________________ Arkym Hood CF, VMR 710 10F 11R, 265/295, OEM Performance Spoiler, Challenge Lip GB, H&R, iND CP, 5/15% tint, MS Air Scoops in Mexico Blue, more coming soon.

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