hondas and exessive condensate

[JHZR2]

Hi,

My GF's 94 acura integra has 165k and runs like a top. It gets relatively good MPG (31k or so). It burns NO oil, leaks none, and UOA is excellent. No coolant loss, nothing that shows up in used oil analysis, etc.

The funny thing is, whether full hot or cold, it always has a puff of condensating vapor out of the exhaust at idle, and typically does it as well during gear changes. It is NOT oil burning - Ive sat and looked at it, sniffed it, etc. I see a LOT of hondas that are driven by ricers that puff bluish smoke between shifts, and you can tell its oil.

The condensation occurs even if its 80 degrees out. I know its vapor, and I have seen other honda vehicles that do similar things. Thing is, I know that the acura does not have water in the exhaust system, is fully hot, runs great, etc.

Any ideas why her car puffs a little water vapor at idle and between shifts?


Once again, its not oil (the line does not drop a fraction of a millimeter over 3000+ miles), not coolant (nothing in UOA, and no apparent loss of coolant). ANd compression is totally fine - it catches on the first cylinder even after sitting for a few days in below freezing winter temperatures. No signs of any headgasket issues either. Passes emissions with flying colors.

Any ideas? Maybe just engine design or thermal design of the engine?

Thanks!

JMH

 

[VaderSS]

I don't know why it shows it's water more than other cars, but you do realize, that over half of the exhaust is composed of water? It's a natural byproduct of burning ANY hydrocarbon.

O2 + HC = CO2 + H2O

 

[Palut]

I had my mom start my car (95 Accord, 149k miles) up a few weeks back, while I watched the exhaust pipe, looking for signs of burning oil.....absolutely nothing came out of there. I could see the muffler vibrate just a hair as the engine came on, but absolutely no visible gases came out of there. Just my experience, but it doesn't sound like your gf's car is acting normal...

If a cat goes bad, can moisture ever build up in there?

 

[JHZR2]

yes, sir, my profession revolves around hydrocarbon chemistry.

Its just that the condensate is more visible from her car, even when fully hot, than our other vehicles.

JMH

 

[JHZR2]

quote:

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Originally posted by Palut:
I had my mom start my car (95 Accord, 149k miles) up a few weeks back, while I watched the exhaust pipe, looking for signs of burning oil.....absolutely nothing came out of there. I could see the muffler vibrate just a hair as the engine came on, but absolutely no visible gases came out of there. Just my experience, but it doesn't sound like your gf's car is acting normal...

If a cat goes bad, can moisture ever build up in there?

---

Yeah but NO use of oil, 31 MPG, excellent emissions and a mere 3.7 ppm of Fe in 3000 miles (with even less soft metals) seems to tell me that all is well.

It may have to do with the thermal propperties of the exhaust system itself, causing more heat loss than other vehicles' exhausts (I have noticed that the acura exhaust is rather thin and skimpy). This could cause lower temperature of the exiting gas, and thus more condensation as it exits.

Thats just my guess...

JMH

 

[Ken4]

quote:

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Originally posted by JHZR2:
The funny thing is, whether full hot or cold, it always has a puff of condensating vapor out of the exhaust at idle, and typically does it as well during gear changes.

---

There must be excessive water condensation in the exhaust. Maybe even the rockwool in the silencer is soaked! Or maybe she washed her car and sprayed some water in by accident?

Typically after 30mins of driving, there shouldnt be anymore condensation in the exhaust.

 

[JHZR2]

her car did sit for weeks at a time in the past year. Lately it has been used about 50 miles a day. Maybe its slowly drying out... I wonder if the Honda exhausts have a very small drain hole somewhere?

JMH

 

[kreigle]

quote:

---

Originally posted by JHZR2:
The funny thing is, whether full hot or cold, it always has a puff of condensating vapor out of the exhaust at idle, and typically does it as well during gear changes. It is NOT oil burning - Ive sat and looked at it, sniffed it, etc. I see a LOT of hondas that are driven by ricers that puff bluish smoke between shifts, and you can tell its oil.

The condensation occurs even if its 80 degrees out. I know its vapor, and I have seen other honda vehicles that do similar things. Thing is, I know that the acura does not have water in the exhaust system, is fully hot, runs great, etc.

---

My brother's '83 Saab Turbo (150k+) does that too. He started it up the other week to do some work on it, and after running for 15-20 minutes, it still had visible water vapor coming out of the tailpipe and a puddle of water under the exhaust tip. Every time he hit the throttle, you could see it blowing water droplets across the driveway. This car gets roughly 80-100mile/day commutes, with a week on-week off schedule as he rotates it with his '87 900 sedan. My Prelude always has visible water vapor when ambient temps are below 70. More visible after idling, goes away after I've been driving, and comes back when it idles long enough to cool the muffler off.

I think it is just a sign that the engine is performing properly.

 

[SWS]

I have 2 Hondas ('00 Odyssey, '03 Civic), have observed the same thing, and, like you, have wondered about it. Thanks for posting!