I had to replace the Head gasket on my 94 325is 2 years ago. I had the yellowish-mayonaise looking gunk on the oil cap afterwards..and still do from time to time. I thought it was left over gunk from when the head gasket was blown, but after doing multiple block tests,compression&cylinder leak down tests, I've concluded that this is just from driving short trips and condensation getting in the oil. Ronald..the biggest issues with coolant/water in the oil is that it will destroy your main bearings quickly. Also..if you have coolant getting in the cylinders..this can cause hyrdolock or crack the head..bend valves etc. So dont drive it.when my head gasket was blown, my oil looked like chocolate milk. I had constant billowing sweet smelling white smoke coming out. my car started to overheat from a cold start in a matter of minutes. Its likely just a blown head gasket..but have the diagnostics done(i.e Compression&cylinder leak-down tests/block tests) done first. You could also have a warped or cracked cylinder head or block.Hopefully not, but you could even have a broken head bolt. And sometimes they break when you try to take them out. The symptoms can be similar and sometimes the only to see if the head has cracks is to have the cylinder head sent to a machine shop and have it pressure tested for cracks. Either way this needs to be done. Also have the head machined. If you do have to replace the head gasket..i'd suggest having the head rebuilt and replace all the critical cooling system components as well.
Last edited by Andycapps; 01-18-2007 at 02:29 AM.