White smoke from tailpipes

[NetViper]

I was goofing around today in the parking lot and got it on for a second (about 20 ft.) before stopping to turn on the street and a coworker said I had a trail of white smoke coming from the exhaust. Then it stopped after I left the parking lot....

What does that mean?

 

[Lud]

You probably just had condensation or other water in your exhaust system and it was just water vapor or steam blowing out of the exhaust which is fine. I think this is quite likely since you said it stopped pretty quickly.

If you have real white smoke, and it happens even when the car / exhaust is good and hot and you're sure there is no water in the exhaust, it could be trouble. If that is the case, first verify that it's really white and not gray smoke that maybe looked white in the lighting conditions. True white smoke is generally caused by burning either automatic transmission fluid or coolant. Since the NSX doesn't have ATF, it would be coolant, which is bad.

Gray or black smoke is from too much fuel and is normal on the NSX at full throttle, as the NSX runs rich at WOT. At part throttle it's a sign of some sort of trouble, such as a problem with an O2 sensor, MAP sensor, FPR, injector, air filter, etc.

You can easily smell the difference between coolant and fuel burning if you can get someone else to reproduce it while you're behind the car. Plain water of course doesn't smell like anything.

 

[NetViper]

I checked my coolant tank and it is about half-way down.

However, I had filled it to the top of the range about a couple months ago.

 

[Lud]

Why did you fill it a couple months ago, has it been going down? Normally it should not, as it is a closed system. Is there any chance you have air in the system and it just worked its way out and was replaced by some coolant?

If coolant really is vanishing, don't panic yet. Hopefully it is just leaking from the overflow tank/hose or from a coolant hose onto something hot and burning off that way. Then when you're moving the smoke would come out the back of the car. If that is the case, you should be able to see where it is leaking because it will leave a whiteish residue. You will also be able to smell it easily if you open the engine hatch shortly after driving around for a while.

Failing that, you get into more serious issues, the best case of which is a blown head gasket.

 

[NetViper]

I had not checked the coolant level I don't think since NSXPO 2002. The car is not running hot at all, infact it is running great. I did put the new exhaust on it about 2 weeks ago.

We checked the coolant level when we put the taitec on a month ago just to check and we also changed the air filter at that time. I noticed the coolant was about where it is now.. so I put more in.

 

[NetViper]

Did a drive with the gf behind me and she didn't see anysmoke at all while we were driving.. i ran it to redline twice...

When we were in the parking lot, i revved it again and she saw a "tiny" puff of white smoke from the far right tail pipe... then we drove back and I redlined it again and she saw nothing..

Any more thoughts??

I am starting to get a little worried.

:

 

[tararan]

is the car running smooth?

i agree with lud, its just condensation or blown head gasket.

but if its a blown headgasket you will definitely notice it. its not something you can miss.

i don't know how you would blow it though. you got boost?

 

[NetViper]

No, no boost at all. All stock except for the exhaust installed a couple weeks ago.

Infact, the car is running great... Very strong.. had it up to 120 MPH on sat. and it was running amazing.. no loss of power, no funny smells.. nothing...

 

[apapada]

What does that mean?

When you check the coolant tank, do you see any oil spills in it, or just coolant ?

Next time you see that white smoke coming out, CAREFULLY try to have a towel to "capture" those fumes (BE CAREFUL, HOT EXHAUST GAS CAN BURN YOU). When the towel is safe, try to smell it if you can detect any "sweetness"...

if you answer either "oil" or "sweetness" on those two tests, your head gasket is blown.

 

[NetViper]

Here is an update.

I tried to add more coolant tonight. As I poured it in, it just went right onto the floor. So I guess there is a big leak there... either a hose or the bottle.. not sure...

Is this a good sign for me??

 

[tararan]

if it is infact leaking then you may be able to scratch out the blown headgasket away. someone correct me if im wrong.

FYI - when i installed exhaust system on cars it's normal for it to show some smoke and funny smell for a few hundred miles. if the system is brand new.

how many mile have you put on the exhaust?

 

[NetViper]

I have only had the exhaust on for 2 weeks, maybe 350 miles..

 

[Lud]

Here is an update.

I tried to add more coolant tonight. As I poured it in, it just went right onto the floor. So I guess there is a big leak there... either a hose or the bottle.. not sure...

Is this a good sign for me??

Yes, it means you probably have a leak in the overflow bottle. If you have the original, that's about normal, the plastic dies with age and use.

Track down the exact source of the leak to verify, then replace the bottle if that is indeed where it is leaking. If it's just pouring srtaight through it should be pretty easy to find the leak!

This is very good news, it's much easier and cheaper than anything in the engine.

 

[Zishan]

NetViper, if it makes you feel any better, my cars sometimes has white smoke too! Usually in the morning on a cold start. I crank it and run inside to do something while the car warms up. Come out and I've seen a tad bit of white smoke. I always assumed it was moisture. Like how some cars leak water from their tail pipes with the a/c on. I just felt it was a bit of water in their from when the a/c was on.

 

[apapada]

NetViper, if it makes you feel any better, my cars sometimes has white smoke too! Usually in the morning on a cold start. I crank it and run inside to do something while the car warms up. Come out and I've seen a tad bit of white smoke. I always assumed it was moisture. Like how some cars leak water from their tail pipes with the a/c on. I just felt it was a bit of water in their from when the a/c was on.

what you describe is normal. What Netviper describes is however different imho.

 

[NetViper]

Well, we took a look at it today.. put in more coolant... it did not drop through this time.. my friend thinks it was the overflow valve that it came out of...

We checked the oil (perfect), revved the car repeatedly and there was NO smoke at all.... The car does not over heat at all and there is no sweet smell from the exhaust.. just smells like fuell... but I can say that ANYTIME exhaust sounds MEAN!!

We are now going to measure the coolant over the next few days and see if there is a problem with the bottle or hoses..

 

[bizman]

head gasket cost???

Just wondering if anyone here has had to have headgasket changed and if so what was the cost , labour , parts etc. Just curious how big and expensive a job it is.

Thanks Wade

 

[NetViper]

Re: head gasket cost???

Just wondering if anyone here has had to have headgasket changed and if so what was the cost , labour , parts etc. Just curious how big and expensive a job it is.

Thanks Wade

I was loosely quoted near $2000 for it.

 

[tararan]

its a big job. i can't imagine doin it on the X. i wanna see a prof. tech perform this process..