My car had a problem starting got it run but ran rought and had no power i check the oil but the dipstick is missing so i took the cap off where u put the oil in and it was milky woundering what might be wrong could the heads be leaking or something else i am going to change the oild and buy a new dip stick do u know what kind of oil i should put in it. It has 80000 miles on it. After how many miles should you change the spark plugs and the timing chain