Water from exhaust at start-up: Condensation or head gasket?

[The_Handier_Man1]

From: Boise_Chief1  (Original Message)
Sent: 2/7/2005 12:50 PM

I've just recently purchased a 73 chieftain with the 440-3.  When I start it up I get a a fair amount of condensation or water comming out of the tail pipe.  Is this normal for a MH in cold weather.  It doesn't smell like anti-freeze, and the oil is clean and as far as I can tell the antifreeze is clean but I may have to over fill it and see if anything floats up.

Any help would be appreciated.
Sean



From: denison
Sent: 2/7/2005 2:28 PM

How humid is it where you are?
    Remember that each gallon of gasoline burned in the engine turns into (mostly) about 18 pounds of hot carbon dioxide gas, and about 8 pounds of hot water vapor, (which amounts to one gallon).  The water vapor condenses in the cold exhaust system at first, mostly the muffler.  In ten or 15 minutes of running the exhaust system will get hot enough so the water vapor doesnt condense inside the exhaust pipes/muffler anymore, and it will be boiling out the initial amount of condensed water too.  If it takes half a pint of gasoline for the engine to run for its first 5 minutes, thats the amount of water that will be coming out the tailpipe shortly.  In chilly humid weather the result would be more noticeable than in hot dry weather.
   Any amount of water vapor that gets blown past the piston rings condenses in the cold motor oil of the crankcase.  It doesnt get boiled out until the oil gets hot enough for the water to turn back into a vapor - which also takes longer in winter weather.  Along with the water vapor are sulfides, chlorides, etc.  These combine with the water molecules resulting in tiny amounts of sulfuric and hydrochloric acid in the crankcase. 
    I think my 413 V8 would run for about 2 minutes on half a pint of gasoline, even when it is warm:  An idling gasoline engine has lousy energy-conversion efficiency.   Diesels are inherently much better about this.



From: Boise_Chief1
Sent: 2/7/2005 5:10 PM

The temp is right above freezing.  I don't think it's "humid"  although there is a certain amount of humidity in the air.  Right after startup there is noticeable dripping out the tail pipe and if you rev the engine there is a fair amount expelled (1/4 to 1/2 cup total). It's a 26 foot chieftain and the tailpipe exits from the rear.  I am not sure if it's so cold that water vapor condenses in the long pipe and is blown out with exhaust gases. 
The MH is so much longer than any other vehicle I'm not sure if the exhaust pipe would ever warm up in this weather.  It seems to be the perfect setup to recondense gasses and I'm just a little nervous.  I guess that my easy question is, has anyone else noticed this happening in cold weather.



From: denison
Sent: 2/7/2005 5:57 PM

I dont watch the tailpipe on my cars, I just get in and go. With the winnebago, I start it mostly in mild weather, and am usually busy checking the tranny fluid, looking for carb leaks, looking at the fuel pressure, the oil pressure, etc.
. Also I have a gravel driveway, and dont notice water sports much.



From: OldEdBrady
Sent: 2/7/2005 7:25 PM

I've had the same thing happen with several different vehicles.  Hot weather, cold weather, it doesn't matter.  Sometimes it is the gas itself.  Depends upon how it was made.  Sometimes, it's just as previously described with the amount of moisture in the air, in the gas, and all the junk coming out of the tailpipe.  I've never had a problem with it, although, in the early days (just after we quit using horses all the time) I used to worry about it.



From: HeavyHaulTrucker
Sent: 2/7/2005 9:42 PM

Boise_Chief, I spent some really cold days in Amarillo, Texas recently -- as cold as 5 below.  There were some mornings that I looked like a steam locomotive for the first half hour after I started her up.  I have the 440-3 in a 21' Brave, with the Edelbrock 1407 Performer carburetor.

John