I have an 04 g35 coupe with around 100,000 miles. When I started it up today, I noticed 2 things:

1. smoke/vapor was coming out of the exhausts even minutes after I turned it off. It didn't smell like burning oil or anything. Oil was recently changed.

2 (MOST IMPORTANT)..every time I blipped the throttle when it was in park (up to maybe 3000 rpms), I heard this swishing water sound. It sounded like a waterfall. Its not loud but it is definetly noticable without trying too hard. It stops immediately after I took my foot off the pedal. It made the sound when I drove off as well.

What do you guys think this is?

Thank

 

we need to hear it..writing this doesnt help but worst comes to worst take it to the stealership

 

ill try to record it later...but just think of surging water. Thats what it sounds like

 

how does the coolant look?

 

Keep a CLOSE eye on the oil. If it looks like moisture or water is in the oil then shut the car off and have it TOWED to the dealer. You could have a blown head gasket.

 

The coolant is fine.

How can I tell if moisture or water is in the oil? Would it just be from the steam coming out of the exhaust after the engine is turned off? Does the slushy water sound heard when pressing the gas pedal (read above) have anything to do with it?

 

The oil will usually appear milky on upper part of the dipstick if coolant has contaminated it... Draining into a wide pan and seeing lots of small "water bubbles" on the oil's surface will confirm the problem. A head gasket is the usual suspect. At that point, assuming no other obvious cause, I'd do a leak-down test of each cylinder to try and determine which head might need a gasket...

 

yeah i agree with some of the people above... blown head gasket?

check for oil in the coolant... or coolant in the oil... if you take a look at your dipstick or oil cap, and it looks like a creamy milky milkshake, then you got urself a blown gasket

 

not too sure about the "slushing" noise ur talking about though

 

Ya I dunno about the "waterfall" ish

 

do you have HFC's or TP's?

 

Air may have made it into the coolant system and you have an air bubble trapped in the lines. Have you opened the system or added any recently?

 

ah... i think i might know what you're talking about for #2.

does the waterfall noise only occur during cold start? or all the time? if it's the former, then i believe it has something to do with the brake cylinder "warming up"...
after a cold start, when you take off do you hear a slight "burp", maybe even possibly feel it on the brake pedal? after hearing that noise on my coupe, the waterfall noise disappears.

on the other hand, if it's on the latter then... i'm not sure.

 

everytime ive heard what your calling the "waterfall" sound in a vehicle its been air bubbles in the coolant system - and yes the coolant system will appear full. typically this happens after a coolant service, but can happen if the headgasket is blown by exhaust fumes getting in the coolant system.

crank your car and smell the exhaust, if it smells sweet, you definetly have a bad headgasket.

Good luck and let us know what you findout!

 

Could it be the HVAC system??