Guys,

I am losing coolant at a pretty rapid pace, about 1/2 of the expansion tank a day.

I do not have white smoke or really any abnormal behaviors...just losing coolant...no puddles nothing...what gives?

There were some oily like substance in the expansion tank but my oil is not milky

 

Go pressure test the coolant system up to 18 pounds for 15 to 30 minutes, you will find it.

 

its a pin hole leak in your rad you can't see it leak but you can lose that much coolant in the time span. pressure test and you will find it.

 

And if leak is found to be in the rad, don't use stop leak except to get back home. You can pull rad in under 30 minutes, and take to indy shop, where they can rod out the calcium buildup, flush with hot acid, and solder up any small leaks. About $70 when I had it done. There is also a $232 replacement radiator available now, but it will be aluminum rather than the oem copper and brass. A new aluminum radiator will cool better than a sludged up old copper one. But the leak can be anywhere, hoses, water pump, various engine gaskets, even the expansion tank connection which is harder to see.

 

Pressure testing Thursday at a local shop. I lost another 1/2 expansion tank full...no leak around the tank, there are some residue inside the expansion tank (like an algae), exhaust does smell a bit sweet..and my MPG went from 14mpg to about 12mpg

 

If it's running rough or starts to I can assure you it's a head gasket. If it is getting into a cylinder you'll notice a light amount of steam coming from exhaust. Sometimes at idle it's hard to see, it will show once you hit the gas.