OK, my wife said car had a little knock on the way home from work yesterday. I checked the dipstick, and instead of nice dark oil color, it was a light brown and seemed "foamy". Is it headgasket? And any idea what cost would be to replace?

 

OK, check the coolant for colour & level in the expansion tank. If the head gasket is shot, the coolant should have discolouration, fuel odor, and the level should be dropping. Also, start the engine and see if you can smell coolant, as well as a sign of white exhaust gas. If the car has had a history of overheating, the head gasket could be a suspect.

Condensed moisture also causes "foaming" of oil on the dipstick, which is nothing to be concerned of.

If the knocking persists, try using different gas station, and if you're not using premium, try using premium fuel. The ECU should adjust the ignition timing for different grade fuel but is worth a try.

Fresh oil remains light brown for a few hundred miles, but if you haven't had oil change recently, you may want to change it again with 10W-30 + OEM filter (MANN).

Other members would be replying as well. See what they have to say.


JPN

 

I have the foaming issue on our 850 Turbo that my son drives as well, but mainly in the winter. It has been due to condensation during the cold weather and it is fairly intermittant.

I would follow JPN's advice, but I would add..... Keep an eye on it and change the oil to see if the problem persists. Use an engine flush if you desire to make sure you have cleaned the crud out. Replace the little black O-ring on the plastic part of the dipstick. Finally, use a good quality synthetic oil if you are not doing so already.

Glenn