Water drained out. What damage?

Sounds like disaster barely averted. If it still runs and seems normal, you're fine. You may have shortened the life of the engine but there's really nothing to be done about it unless you wanted to rebuild it. I would change out the coolant back to the proper mix of antifreeze and water (you have 100% water in there now, right?) and also change your oil (you may have cooked the oil) and filter to be safe. After that, just drive on.

If you did anything serious (usually a cracked block) the car wouldn't run at all. Change the above fluids, call it a learning experience, and don't do it again, drive on.

Thanks Matt. The tip about the oil & filter sounds right. I'll change both. As the car was slowing down I guess this was because of increased friction between piston and cylinder which means a lot more wear. Is that right? Thanks again

RD

Matt B. wrote:

You just need to drive it to see if any antifreeze is migrating to the oil. Usually you will see a white foam on the dipstick if there is excessive moisture in the oil. True test is after you got you mix back to 50% water 50% antifreeze is first to see if the water level drops. Second is to see if water/antifreeze makes it to the oil. It might take a few thousand miles to test if there is a minor leak. You could send your oil off for an analysis but they want a few thousand miles on fresh oil before they can give a true report.

You should still have oil pressure lubricat>Thanks Matt. The tip about the oil & filter sounds right. I'll change both.

Thank you Jim. More good advice. Unfortunately my old Passat doesnt have engine management but according to the rev counter the engine speed has not changed. Cheers for your help.

RD

Jim Behn>You just need to drive it to see if any antifreeze is migrating to the

Not sure if it's so much that as it might be more a function of increased temperatures and fuel/air and combustion temperatures not being ideal as the general engine temperature goes up. Cars usually have more power at lower temperatures anyway (such as in winter time when cooler air is coming into the intake) so if your engine was bastically marinating in heat, all of that could have combined for conditions to lose power.

As others have said, change the coolant and oil and watch over some time for coolant getting into the oil and watch for any abnormal smoke (compared to before you overheated). If the car already is old, you might have some smoke already just from wear and tear in general. But if the car behaves typically and all fluids look normal afterwards, just drive on.