Please help me diagnose smoke

[skate1968]

I did a little experiment with my car, a 1991 oil consuming honda civic. I stood behind my car to get a good look at exactly how much of smoke screen was coming out of my exhaust pipe. I did not see any smoke while the car was idling. Good start. Step 2 I had a someone step on the gas pedal while the car was running in Nuteral. No smoke! I'm thrilled! My car didn't smoke under moderate increases in RPMs! Perhaps the Moly in the VSOT (valvoline synpower oil treatment) helped the oil burning? I'm not sure why but i'm certainly NOT complaining. Step 3 My friend gave it more gas. Stepped harder on the pedal-- high rpms. Then it started smoking-- big time. My car will burn oil at high rpms, which i already knew. Overall i'm pleased with the results of my test. My car isn't smoking as much as i thought it was. Later outside the car wash i again let the car idle. Smoke??? Smoke when idling with no one reving it??? Why would my car start out by not smoking under moderate rpms. Then fifteen minutes later it is smoking without being under any kind of load? without revving up the engine into high rpms? Another thing i noticed was fluid dripping out of the exaust pipe. Drip drip drip. I never noticed this before. So my bottom line question: Why do i see fluid dripping from my exhaust? Cheap gas? Water in the gast tank? (Please don't be antifreeze from a leaking head gasket) Is this fluid contributing to the smoke coming out of my tail pipe? I would imagine that it is. Thanks for reading. (by the way, I discovered that oil is slowly seeping from the after market oil cap on the crank case. You'd think that would be a simple enough part to manufacture properly.)

 

[Drew99GT]

The fluid is water vapor, one of the byproducts of ANY combustion whether it be gasoline or wood. That's why you see steam coming out tail pipes on a cold morning. Unless the fluid is obviously oil...

 

[Drew99GT]

Oh, oil gets by my aftermarket oil cap as well since my car has a lot of blowby.

 

[Quest]

The byproduct of burning gasoline is water vapour (H2O) and CO2, assuming everything is in good working order (CAT, emissions component, engine isn't worn and/or burning oil, etc.) So the liquid you are seeing dripping off of your tailpipe, so long as it's not oily, it's normal then. There is no correlation to fluid coming out of your tailpipe and the smoking. As for your smoking, it could be one or more of the following: (a) head gasket leak: if your smoke smells somewhat sweet and white in colour (under bright sunlight), you are having coolant leak. If your engine is coughing blue smoke and smells like 2 cycle lawn mower engine, something to do with the mechanical part of your engine. When in doubt, always replace your PCV valve and hose first. Then check to see if you have stuck oil control ring issue? worn/scoured cylinder wall, worn valve guide or valve guide stem seal issue. These will require professional help. Good luck.

 

[mechtech2]

Like posted above, the water dripping is normal, and could also be the surce of the smoke. Is the inside of the tailpipe very oily or sooty?

 

[skate1968]

Thanks to all who responded. After a bit of reading i realize that water dripping out the tail pipe and the steam which i mistook for smoke have nothing to do with my oil burning. And Quest, thanks for your input. But i've already diagnosed my oil burning to be worn piston rings/blow-by. (i'm sure some would say that i'm beating a dead horse) (i wrote this thank you post yesterday, also. But for some reason it didn't post.)