Can anyone tell me the sign of Head Gasket gone on bmw e46?

Signs of head gone..

Oil in expansion chamber / oily smell

Mayo on oil filler cap

White or blue smoke in excess from cold startup

However....I will say that with modern engines now using thinner and thinner oil there is a tendancy to collect oil residue under the filler cap and dipstick naturally. Typical examples are cars that use 5w30 grade semi synthetic oils. ie Mazda RX8, Audi A4 3.0 etc.

Check your oil type first it could be normal residue, if you're still worried theres a simple gas test that can be used to check the expansion chamber gasses to work out whether the heads gone or not. Any decent garage should be able to do this for as little at £20.

" i took the header tank lid off and the water boiled over...? but the car was hot and i think there was a bit to much water in it. (so it would boil over right?)" Yes that's right - even with the correct amount of water. It's not a header tank like your central heating system at home - it's a pressurised expansion tank. However, 1st I would invest £10 in a new cap to make sure that's not contributing to yr problem. BMWs are notorious for silly little water leaks that can render them immobile - very often it's one of the brittle black plastic parts - prime culprit is the thermostat housing. They are NOT notorious (AFAIK) for head gasket failures. Next time it's steaming, open the bonnet and have a good look. Also, carefully clean/wipe around the hose connections and then look again a few days later to see if there's any staining. Good luck

Hiya, The first thing I would check is that the engine breather is not blocked, Cos all engines compress air & in compressed air you have water, If you not loosing water, no lack of power, That would be the first thing I would check,On E46 if you take off the oil filler cap while running you should hear a engine sound change, If you hear a very big differance then, Have a look at the breather.... That would also give you the yellow gung on your oil cap

was it on the dip stick in the oil and just uder the cap if under the cap more likely just cap wasnt sealed and it got wet if the oil is milkly or color of peanut butter then yes head gasket some times when it rains or in winter some cars will get water on top of oil cap and it gets under cap so if your cars not been run hot and your oil is clean on the end of dip stick your fine

sound like it ..but it can be just age ..while engine is cold ..remove rad cap .start engine ..you will get some water movement ..but not a lot ..if you are getting a surge ..or air bubbles ..or both ..but if still running well and you are not losing water ...and exhaust is not blowing white ..then its emulsion you are seeing ..look inside oil filler cap and you will see more

If water mixes with the oil it will change the color also if you have white smoke coming out the tailpipe is a sign also.

Get a CarMD. I use this to tell what's wrong with my car. It's very reliable especially if you don't want to go to the mechanic and get a diganostic check, as it is very expensive.

www.carmd.com

Check it out. I hope this helps.

The car would over heat , or scip or misfire , oil residue in radeater, coolint or water in oil crankcase,you may try a compretion test,

The oil level will go 'up' instead of 'down'

if its a 316 then probably yea.... bloody poor engines.