Im I on the right track?

[2ndwind]

My FI car has been leaking oil down the sides of the block from the head gasket and cam box gaskets worse and worse over the past year and a half. Yet it has run very strong with excellent power (occasionally accidentally chirp the tires). The oil has remained clear (not brown muddiness as with water in it). No smell of antifreeze at the exhaust. Everything has working fine for a year (once I put in a starter relay), temp gauge would read about 195 when fan came on which drove it down to 190. Recently, I've been having trouble with the car not idling after I run into the store for a few minutes.

After two short runs on Friday with lots of trouble idling after restarting on second run, I noticed the temp gauge climbed about halfway between 190 and red. I couldn't tell if the fan was coming on. So I let it sit in my driveway for a bit. The fan came on but the temperature held the same. I turned the engine off, fan kept running (as expected). I turned the ignition key far enough to get the reading from the gauge without restarting the engine. After a few minutes, the fan stopped but the temperature gauge had not moved noticeably. Later when the engine was cool the gauge read zero, as expected. I checked the coolant level in the radiator and it looked a little dark. I stuck a my finger in it then a white rag and they came out brown.

I am assuming the head gasket is now a goner internally, allowing oil into the coolant channels (oil is still normal). Would this account for the difficulty of the coolant and fan to cool the engine to 190? How does one flush the coolant system of oil once the head gasket has been replaced. Is it likely my sensors at the coolant tee and new gauge sensor are messed up for good or can they be cleaned?

Thanks for any additional insights.

[azruss]

sounds to me like you are catching things early enough to not have significant oil contamination in the coolant. If you are doing the head gasket, you will have opportunity to inspect the water passages to see how bad they are. cant see any reason why the sensor arent cleanable.

[majicwrench]

Brown as in brown slimy oil?? Rust can also make antifreeze brown.

[baltobernie]

Concur with Magicwrench. If there was oil in the coolant, there'd probably be vice versa. Water is heavier, so after the car has sat a while, crack the oil drain plug and see if any coolant comes out with oil.

If no coolant appears, and the "brown" in the overflow tank isn't oily, Install a coolant flushing tee at the highest point of your heater hose, and flush with plain water. Button everything back up and see if your problem is solved. If not, try a chemical 2-part coolant flush. Don't forget to leave the heater control on Full Hot during all this.

[2ndwind]

Brown, as in oily brown, not rust brown. I will pull the drain plug to check for cross contamination. Thanks guys.

[jctucker]

Just a little bit of advice: I've found Dawn works really well for flushing cooling systems that have been exposed to oil. It does an awesome job of getting the coating off the insides of hoses and whatnot. Good luck!