Hi guys,
My wife has a 2001 V6 Ford Escape FWD with just under 200,000 miles on it, and it's been having some coolant problems recently that I just can't wrap my head around, and I could use some help in figuring things out. Here's what I know:
-I replaced about 50% of the coolant a few weeks ago with Ford green/distilled water. I say only 50% because I couldn't get the drain plugs on the block to open up, so I could only get coolant out of the radiator. The only way to fill it is through the cap on the overflow tank, and I let it burp and cycle through until the level seemed to stabilize.
-A few days ago I was driving the car around after bedding in new front brakes, then came home and parked it. I came outside 10 minutes later and was greeted by a large puddle of coolant under the car. By the looks of it, it had all come out of the coolant overflow tank vent hose. There was no trace of coolant behind the car in the street or driveway, so I believe it only overflowed after the car was parked. The only thing I could think that might have caused that was that I had overfilled the reservoir, since the driveway goes up hill and the vent hose is on the back of the overflow tank.
Here's a picture for reference:
-I topped it off and we headed off on a ~200 mile trip out into the WV wilderness for a friend's wedding. We stopped half way to find the overflow tank dry again, so I topped it off. After that, the low coolant light would come on and turn off as we drove up and down the hills, but the temperature never budged. I confirmed again that the fans were working.
-Before we drove home today, I topped off the overflow tank twice after it cycled it through the system. Again, after a while the low coolant light would come on and off, but the temperature never moved. We get home and the overflow tank is empty again, and it's clearly coming out through the vent tube. WTF?
I just can't figure out how or why it's spitting out coolant from the vent hose even after the overflow tank is empty. If the coolant was that hot, wouldn't it show as such on the gauge or throw up a light? The water pump is obviously working, and so are the fans. The only normal idea I had was the thermostat, but I couldn't really imagine a situation in which a bad thermostat could make problems like this. The only other idea I have is a head gasket about to go bad. I just did the oil a few days before the trip and I didn't see any coolant in it. But is it possible that the HG is failing in a way in which exhaust gases could be getting blown into the coolant, and forcing it out of the overflow vent tube? I'm about to buy a coolant system pressure tester for $40 just for E36 M3s and giggles to see if I can find any problems that way, but I kind of doubt it. What do you make of this? What else can I do to troubleshoot?
