water in the exhaust

[ahlem]

My 1990 535i 5 speed has been sitting patiently in the driveway for about a year now.
It has ~421,000 miles and the engine has never been opened.
I start it periodically and let it idle for a while.
The last two times, there has been quit a bit of water coming from the exhaust. At least one beer's worth.
I have several critical other BMW projects in front of this one but would like to ponder this for a bit.
I will pull plugs to check them and do a compression test. There isn't any water in the oil.
Unless one of you relieved yourselves into my exhaust, I'd welcome any possible suggestions.
Head gasket corrosion comes to mind but not certain how coolant would get into the exhaust unless it filled a cylinder first.

[whiskychaser]

You may even see a bit of mayo on the oil cap too. I'd suggest it is just condensation.

[shogun]

Probably just condensation, when you start it from time to time, the exhaust does not get that hot that all the condensation goes out, that would require a longer drive.

[632 Regal]

Shogun is right, your building a volume of water from condensation probably being stored in the muffler. Starting and letting it idle is not real good for the engine either. Drive it for a while or keep it in storage. If concerned about the volume of water in the muffler drill a 1/16" hole at the lowest point and let us know how much drained out.

[632 Regal]

I remember a while back when people would panic because there would be a cloud behind the car in cold weather. The cloud would never go away, etc. A lot of people thought it was head gaskets but is actually normal. So I wouldn't worry with only 420K miles, she's just starting to get broken in.

[genphreak]

A hole in the muffler will eventually corrode into a bigger hole. Better to get the water out with quick drives, also helps to lube the trans and diff seals etc, stop them drying out.

Watch your coolant level and if it is dropping whilst standing, you may have a slow leak into a cylinder. It happens with age, at least if you can diagnose it early you will have time to buy the necessary parts and not have to machine anything. It may work/seal fine when warmed up. Waiting long enough for a to cause an overheat or fill a cylinder with water (hydrolock- enough coolant in the cylinder can cause the block to crack with one crank/touch of the ignition key)...

If the gasket is leaking, even intermittently, you may be seeing the first signs. But I'm being cautious.

Old M30 gaskets usually leak coolant to the atmosphere below No 6, or leak into the cylinder at No 6. The block can rust a little around the water jacket back there, just one of the reasons to change your coolant regularly (every 2 years) and to use the exact damned right stuff.