White Smoke

[Alexlind123]

When it is cold, my car emits large amounts of white smoke from the exhaust pipe. I thought that this was normal after reading a thread awhile ago about white smoke and condensation and so on, but when i moved my car out of the garage for a few minutes and then moved it back in a few minutes after that, i noticed a sweet smell. I dont seem to be losing any coolant though, and my oil doesnt look milky. My spark plugs, at least the two i took out, are not white but a brown color that macthes the "The Best" picture on this website http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html.
My question is, should i be worried yet? Is there anything else i can check? Should i take a look at the rest of my spark plugs and post a picture of them here?
I feel that I, with my brothers help, could tackle a headgasket replacement quite competently. I hope that the headgasket does not need replacing though, and perhaps it could be the catalytic converter? Maybe i should replace the cats with "temporary" "test pipes" to help isolate the sweet smell. The smell only occured this once, and i never notice it when getting out of my car or if is it idling (like it was when i warmed the transmission to fine tune the fluid level after changing the transmission fluid).

[wjbell]

Sounds very much like a head gasket. White smoke, sweet smell. Take it and get it tested for hydrocarbons in the coolant system, make sure they check it when cold.

[Kalevera]

People freak out this time of year because it gets colder and the car smokes a lot for a good 20 minutes after startup. Exhaust typically smells "sweet" and the mixture is leaned out a bit if the car is operating normally.

On the head gasket: start worrying about it when the oil and coolant intermix, either way, or consider it a possibility when the car overheats.

A good spark plug is tinged brown. White is usually steam cleaned, which is bad (coolant vaporizing in the cylinder versus AF). A healthy light brown is normal, like in that picture.



best, whit

[Alexlind123]

That eases my worries a bit lowell, thank you. I know my car doesnt (or didnt at the time of purchase) have any overheating problems, as my dad drove it home (with me riding) in 100+ degree weather in stop and go traffic and the temperature needle never twitched above the 12 o'clock mark.

[MBXB]

Won't you always get some water vapor since one of the byproducts of gas oline internal combustion is....H2O?

[Paul in NZ]

also if you are losing coolant AND the car runs roughly for a little bit after starting then smooths out....classic headgasket leaking coolant into cylinder symptom....these cars have large exhasut systems which takea lot of heating up so the exhaust steams for a long time.....

[wjbell]

I was just giving you that advice as better safe than sorry. When I bought my car I smalled a little coolant. I didn't have any white smoke but my upper radiator hose would pressurize to as hard as a rock. I took it in and they checked for exaust gases in the coolant system and it was present. They also looked and found coolant slowly leaking out the back of the head where you can't see it and it was dripping on the exaust and vaporising. That's why I got the collant smell and no signs on the ground. Oh, and it was such a small leak that my coolant level didn't look like it was changing.

They pulled it apart and luckily I cought it early; no head damage. If I had let it go longer it could have damaged the head and instead of $1000 I could have been looking at $2000 and up.

So I was just saying, if you're worried, spend $50 for a test, it could save you some headache later.

[Alexlind123]

I was under the impression that all m30's idled roughly when cold, perhaps i am wrong. Also, the head gasket itself only costs ~$100 so i would be saving $900 by doing it myself over a couple of days. I think i may wait a bit longer on this to see if it gets any worse.

[wjbell]

I was under the impression that all m30's idled roughly when cold, perhaps i am wrong. Also, the head gasket itself only costs ~$100 so i would be saving $900 by doing it myself over a couple of days. I think i may wait a bit longer on this to see if it gets any worse.

I could be wrong, but I think all M30s tend to idle a bit rougher period. If there's a noticeable difference in the idle between cold and hot that's not normal.

BTW, that's how mine was, it would idle rough cold and then smooth out when warm. What was happening was when it heated up it would seal up the coolant leak. When they tested for exaust in the cooling system when it was warm there was no sign of it.

[shogun]

White smoke is unreliable as an indicator because in this day and age of catalytic converters, white smoke out of the tail pipe is common. The converter takes HC and CO and converts it to H2O among other things. Because the converter operates at temps exceeding 1000 degrees Fahrenheit, the water turns to steam and appears as white smoke coming out of the tailpipe.

An easy visual indicator is to look at the oil on the dipstick. If it is brown in color, like a chocolate milkshake, you may have a headgasket problem, causing water to enter into the oil.

The only real way to be sure is a positive mechanical or chemical test such as 1. compression test 2. cylinder leakdown test and 3. chem test to detect presence of water in crankcase or oil in coolant.

[GS535i]

All the tests mentioned have merit; however, as you first detect the issue on cold start up via the exhaust, coolant inleakage to the oil system is not a concern nor is a headgasket leak to atmosphere. Coolant inleakage directly to one or more cylinders is consistent with this.
The first test I'd do is a coolant system pressure test on a cold engine - if it looses pressure over 15-30 min, pull the spark lpugs and listen ( or swab them for antifreeze).