Water in the exhaust

Driving home the other day, my heater valve started leaking about 2 blocks from my house. I went ahead and drove it home since I was so close. The temp got up close to the red area on the temp gauge. Now perhaps the Jeep has always done this, but now I am really paying attention to it. When the engine is cold, I get (what looks to me like) a lot of water from the tailpipe and the muffler weep hole. The water is clear and has a slight metallic smell, but nothing that would indicate coolant. When the engine is hot, the exhaust still has a damp feel to it. Since I replaced the heater valve and all the heater hoses, the cooling system is very tight and doesn't seem to be losing a noticeable amount of coolant. The engine runs just as great as it always has, and my oil is coolant-free. Is this a problem, or is it normal?

The only thing I could think of was that when my heater valve went, it blew about 1/2 gallon of coolant right onto my vapor canister. Is it possible that water could have gotten into the canister?

As far as I know the HVAC and exhaust systems are independant, so getting coolant into your e-vac can is unlikely. This is probobly normal condensation from the combustion.

Gas + O2 -> H20(g) + C02(g) + other compounds

Essentially the burning gas makes water vapor and due to the cold ambient temp. outside it's condensating and is more noticable.

Yep some amount of water is normal byproduct of engine operation. You see less of it when the engine is hot because the exhaust is hot, and its burning it off. You may have unintentional levels of oxygen though, so you may want to look at your exhaust manifold or catalytic converter for any new holes or cracks.

Coolant levels will also jump up and down quite a bit in town since there is no forward momentum to passively cool the system and the fans don't come on until higher levels. It should not get that hot though, so you may want to check that your main clutch fan is operating correctly and that the car is not relying exclusively on the electric fan for emergency cooling.

rockclimber24315 said:

As far as I know the HVAC and exhaust systems are independant, so getting coolant into your e-vac can is unlikely. This is probobly normal condensation from the combustion.

Gas + O2 -> H20(g) + C02(g) + other compounds

Essentially the burning gas makes water vapor and due to the cold ambient temp. outside it's condensating and is more noticable.

Click to expand...

X2 - Check out the exhaust on the other cars on the road in the morning.

Some condensation is normal especially right after start up and/or short trips. When in doubt I use a piece of white paper towel and let it drip on that, if it's coolant you can often see a stain (tint) the same color as your coolant.
At high humidity your motor can pump out over 2 quarts of water an hour at 1000 RPM's (though my math is likely flawed). Simply, a cubic yard of air at high humidity can contain near an ounce of water.

Thanks for the info, guys. I understand that condensation is a normal byproduct of combustion, and I had hoped that's what I was noticing, I was just concerned that I started to notice it after I got my engine good 'n hot.

I had my exhaust checked at Midas last weekend, and they couldn't find any leaks or holes. The PO had the '96 emissions reprogram and cat inspection done recently, so I would assume that the cat is still good.

My cooling system should be in good shape now, since I have a 3-core radiator, a recent looking water pump, and now new heater hoses and heater valve. The reason it got so hot was that the heater valve failed.

Is there a test for proper operation of the fan clutch? When the engine is cold, I can hear it, but not when the engine is hot.

When the engine is cold, the fan should move with minimal effort by hand, but should not spin freely or loosely. After that, warm up the engine and let it idle until the engine gets warm and see if the clutch engages. I don't know the exact temperature threshold (don't have the FSM here), but it's basically a thermomechanical clutch that engages as the engine warms up.

Hey, the water coming out of my tail pipe smells like metal!!!!

Well, no kidding man, think about what you just said!!!!!!!

keep0njeepin0n said:

Hey, the water coming out of my tail pipe smells like metal!!!!

Well, no kidding man, think about what you just said!!!!!!!

Click to expand...

Well thank you, sir, for pointing out what an idiot I am for attempting to accurately describe the symptoms I was concerned about.

I am an FAA certificated A&P mechanic with several years of experience on both reciprocating and turbine engined aircraft, and I know that the absolute worst thing you can do when asking for help is to leave out information. The slightest detail can make a huge difference in where you start your troubleshooting.

Since 99% of aircraft engines are air cooled, automotive cooling systems are one area where my knowledge is lacking. Transmissions are another.

Daedalus454 said:

Well thank you, sir, for pointing out what an idiot I am for attempting to accurately describe the symptoms I was concerned about.

I am an FAA certificated A&P mechanic with several years of experience on both reciprocating and turbine engined aircraft, and I know that the absolute worst thing you can do when asking for help is to leave out information. The slightest detail can make a huge difference in where you start your troubleshooting.

Since 99% of aircraft engines are air cooled, automotive cooling systems are one area where my knowledge is lacking. Transmissions are another.

Click to expand...

Yeah I know what you mean about leaving info out. I too am in the aviation industry, but on the avionics side of the house. I hate it when you get those gripes that say things like "broken", or "does not work"....drives you nuts everytime.