Sounds safe to drive to me! If the headgasket is bad ull be loosing cooalnt. Also on teh pcv valve, oil dipstick and oil fill cap there will be a foamy white or foamy green substance, if thats there suspect headgasket issues, also oil in coolant will indicate this.
They have a few easy tests to check for blown headgaskets, some with ph paper, others with pressurizing the cylinders, or checking a cylinders compression.
White exhaust could also indicate excessive moisture in the gas.
Wednesday, March 11th, 2009 AT 9:40 PM