I have an 04 VW Passat. I know it needs a new pcv valve. Could that cause the engine overheating and boiling over with white sludge? What could be causing this problem?

  • Welcome to Motor Vehicle Maintenance & Repair! Sounds like you've got a blown head gasket. Feb 17, 2018 at 23:44

1 Answer 1


Sounds like a blown head gasket is def your issue, the milky sludge is from engine oil mixing w/ coolant. (You didn't recently add any leak-stop to your cooling system right?) You would see bubbles form in the overflow tank or radiator(be very careful opening while hot since spray & boil over is an issue), loss of coolant, possiby w/ no visible leaks underneath the car, & due to this, the engine overheating. A completely blown head gasket will show excessive leaking of coolent. You may have misfires at ignition, loss of power while idling & if the car starts it might not restart after being driven. Hopefully you've discovered the problem already as I'm a bit late. You're prob also seeing white exhaust smoke at ignition. Hope this info helped from a single female who had 2 learn all about cars at 16 when the combo Ford/Mazda Probe she bought was a POS & to keep from going broke tried 2 diy everything. Lol

  • You can also test your coolant for co2, to make sure. You local repair shop should have a testing device.
    – Daniel
    May 7, 2018 at 13:38

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