How can I tell what smoke is coming out of my tailpipe?

Question

I don't use any oil on my 4.3 vortec chevy.It has 120k on it and runs perfect.But have been adding coolant for the past 2 weeks and no leaks in the garage floor.Only smokes on a cold start or after sitting a few hours.No water in the oil,or vise versa.Any ideas?

I can't really tell by the odor,it's not black for sure.So fuel isn't a worry.It looks white which would account for the coollant lossI had oil changed this week,nothing mixed in with it,no seperation in the oil showing water..But where is it going and what can I do to stop it?

Now that coolant seems to be the problem what do I need to do to tell what's causing it,how it's leaking in and verify it before having any work done?Should I pressurize the system or have the intake removed?What should I be looking for?

Answer 1

I own a shop, and we can all speculate for days. The thing to do on this one is to take it to a mechanic, and have them pressure test the cooling system to determine where the leak is. They will be glad to tell you what the problem is, and give you an estimate on the cost of doing the repairs. Most shops don't charge you to give you an estimate, but make sure before they look at it, or they could stick you with a bill. Ask them what they charge to tell you what is wrong & give you an estimate on repairing it. Smoke after sitting can be bad valve seals, leaking injector system, or leaking head or intake gaskets. Like I said, we shouldn't speculate, but gas smoke is black, oil smoke is blue, and coolant smoke is white.
Part 2:
From what you are saying; it really looks like you are burning coolant, and yes it will burn some of it, evaporate some, and send the rest out the exhaust pipe. This means several things; One, you may have a blown head gasket, two; you may have a leaking intake gasket, three, It could have a cracked block, or head. Some tests needs to be ran to determine the exact cause, and location. First a compression test to determine which cylinders are the culprits. A leak down test to determine if its between two cylinders, or just one cylinder. No coolant in the oil is good, but it can be there and you not see it. A pressure test with some dye added, and check the dipstick with a special light, will tell if any is truely getting into the oil. It can be there, and not be apparent. I have seen this problem resolved by using some stuff called "K&W Block Seal" in the cooling system. One must follow the directions to the letter in order for it to do the job properly. If this doesn't fix it, then the intake, and the head on the leaking side must be removed, the problem found, and repairs of the cause done. Going with the odds, it is most likely either a leaking intake gasket, or head gasket. This is a pretty expensive job to have done, so using the block seal is an option, and trading the vehicle is another one. The 4.3 has an aluminum intake, and they sometimes will pit in the corner, but they usually leak to the outside of the engine, but may also leak to the inside into a cylinder. A head gasket will leak from the coolant passage into the cylinder. I would give the block seal a try, and if you don't have results that are satisfactory, then you will have to go with your options.
Glad to help out, Good Luck!!!

Answer 2

White smoke, coolant. Black smoke, fuel. Blue smoke, oil. If it's white as it goes on to say, you have a pressurized coolant leak into either the intake area or a direct leak into the cylinders. Either way, stop driving and get it looked at right away as the more driving you do the more damage you will do.

Answer 3

If coolant was getting into the cylinders, it would seap in overnight usually and then would run rough when started cold. If it runs perfect I would look harder for an external leak first. If coolant was going straight into oil, I would suspect intake gasket, and there would be alot of white muck on the bottom of oil filler cap.

Answer 4

i had the same problem with my 2003 5.3 vortec. For about the last year i have been adding 1.5 to 2 gallons of antifreeze to the truck every month. i kept bringing the truck in to the mechanic and they told me that it was the radiator cap. That was bogus, the just did not know were it was going. well about 6 month ago my oil slugged up and the problem with that is i run full synthic and it baffled me. Long story short i got a new motor in the truck know because it was leaking antifreeze through the head gasket.