tdenhartigh
Well-known member
During my drive from Michigan to Massachusetts my car (1998 Jetta TDI 190k) lost over 3 gallons of coolant. We had to stop somewhere between every 100 to 150 miles to fill up the recovery tank. The engine never overheated…either the coolant light started flashing and we’d pull over, or I would notice the temp gauge climbing…anything over 190 deg and I would know the coolant was low, so I pulled over. Before the trip I had noticed the car was loosing coolant, but because I don’t drive for 18 hours strait every day, I didn’t know that it was such a major loss of coolant.
The only visible wet area in the engine is right by the coolant recovery tank. Both the upper and lower radiator hoses are hot (therefore I’m assuming the thermostat is working). The whole radiator gets warm (therefore I’m assuming there’s no stoppage of water flow in the radiator).
When I got to Mass I started reading threads here to see if I could find a similar problem. My first thought was a head gasket failure, because, like I said, the recovery tank was the only area that was wet (I thought the engine compression was putting extra compression into the cooling system and pushing it out through the cap while I was driving. However, I drove with the cap really loose to see if, by relieving the pressure, the coolant loss would still occur…it did. Also, there are no signs of oil in the recovery tank. Therefore my first theory is shot down.
That brings me to today’s test. Last night I went to the car wash and sprayed down the engine so I could see if there were any spots that were getting wet with coolant that I just hadn’t noticed before. Today I ran the car in the garage to look for any signs of coolant loss…here’s the results:
Time: 0 min
Engine Cold
Coolant level was just below the “max” line when starting the engine.
Time: 10 min
Engine Temp: 160 deg.
The recovery tank has been getting fuller and fuller. At this time the water started pouring out of the lower weep hole.
Time: 20 min
Engine Temp: 190 deg (note: from here on out the engine temp stayed at 190).
The coolant stopped leaking out of the lower weep hole. The recovery tank remains too full, i.e. just below the lower weep hole. Steam is coming out of the lower weep hole.
Time: 30 min
Tried turning the heat on and letting the heat go at full blast for 5 min…no change in the coolant level (still just below the weep hole). Steam is still slowly coming out of weep hole.
Time: 40 min
Leaking out of weep hole still stopped, however, when I rev the engine up and down (1000 to 4000 to 1000 to 4000 etc) extra steam comes out of the lower weep hole…the hole also spurts out coolant (see pic below). When I keep the engine rpm’s constant (at about 3500 or so) the coolant does not come out of the weep hole, and the steam coming out stays at the slower rate.
Time: 50 min.
Drove the car hard for 10 min. at about 40-50 mph (2500-3000 rpm’s in 3rd). When returning to the garage, the coolant level was just below the seam in the recovery tank. After idling for only 2 min. the coolant was back up to just below the lower weep hole.
Time:80 min.
After a 30 min drive, I pulled into the garage and the coolant level was just below “min”. After idling for 1 min. the coolant was up to the “max” line. After one more min. of idling the coolant was about halfway between the flange and the lower weep hole. Steam continues to come out of the lower weep hole. The area around the recovery tank is wet with coolant. Prior to the drive I had wiped the area down.
Time: 90 min.
Idled for 10 min…coolant level stays about halfway between the flange and the lower weep hole. Turned the engine off and in about 10 seconds the coolant dropped to about 1” below the “min” line.
Summary:
When the car idles the coolant level in the recovery tank rises above the max line, in some cases it rises too high and goes out of the lower weep hole. When driving the coolant level seems to lower, however, there’s still coolant coming out of the weep hole. After a drive, letting the car idle, the coolant level goes back up above the “max” line. When I turn the car off the coolant level drops to below the “min” line.
Why is this happening?
Sorry for the long post, but I wanted to get all the details out there. Thanks in advance.
Tim
The only visible wet area in the engine is right by the coolant recovery tank. Both the upper and lower radiator hoses are hot (therefore I’m assuming the thermostat is working). The whole radiator gets warm (therefore I’m assuming there’s no stoppage of water flow in the radiator).
When I got to Mass I started reading threads here to see if I could find a similar problem. My first thought was a head gasket failure, because, like I said, the recovery tank was the only area that was wet (I thought the engine compression was putting extra compression into the cooling system and pushing it out through the cap while I was driving. However, I drove with the cap really loose to see if, by relieving the pressure, the coolant loss would still occur…it did. Also, there are no signs of oil in the recovery tank. Therefore my first theory is shot down.
That brings me to today’s test. Last night I went to the car wash and sprayed down the engine so I could see if there were any spots that were getting wet with coolant that I just hadn’t noticed before. Today I ran the car in the garage to look for any signs of coolant loss…here’s the results:
Time: 0 min
Engine Cold
Coolant level was just below the “max” line when starting the engine.
Time: 10 min
Engine Temp: 160 deg.
The recovery tank has been getting fuller and fuller. At this time the water started pouring out of the lower weep hole.
Time: 20 min
Engine Temp: 190 deg (note: from here on out the engine temp stayed at 190).
The coolant stopped leaking out of the lower weep hole. The recovery tank remains too full, i.e. just below the lower weep hole. Steam is coming out of the lower weep hole.
Time: 30 min
Tried turning the heat on and letting the heat go at full blast for 5 min…no change in the coolant level (still just below the weep hole). Steam is still slowly coming out of weep hole.
Time: 40 min
Leaking out of weep hole still stopped, however, when I rev the engine up and down (1000 to 4000 to 1000 to 4000 etc) extra steam comes out of the lower weep hole…the hole also spurts out coolant (see pic below). When I keep the engine rpm’s constant (at about 3500 or so) the coolant does not come out of the weep hole, and the steam coming out stays at the slower rate.
Time: 50 min.
Drove the car hard for 10 min. at about 40-50 mph (2500-3000 rpm’s in 3rd). When returning to the garage, the coolant level was just below the seam in the recovery tank. After idling for only 2 min. the coolant was back up to just below the lower weep hole.
Time:80 min.
After a 30 min drive, I pulled into the garage and the coolant level was just below “min”. After idling for 1 min. the coolant was up to the “max” line. After one more min. of idling the coolant was about halfway between the flange and the lower weep hole. Steam continues to come out of the lower weep hole. The area around the recovery tank is wet with coolant. Prior to the drive I had wiped the area down.
Time: 90 min.
Idled for 10 min…coolant level stays about halfway between the flange and the lower weep hole. Turned the engine off and in about 10 seconds the coolant dropped to about 1” below the “min” line.
Summary:
When the car idles the coolant level in the recovery tank rises above the max line, in some cases it rises too high and goes out of the lower weep hole. When driving the coolant level seems to lower, however, there’s still coolant coming out of the weep hole. After a drive, letting the car idle, the coolant level goes back up above the “max” line. When I turn the car off the coolant level drops to below the “min” line.
Why is this happening?
Sorry for the long post, but I wanted to get all the details out there. Thanks in advance.
Tim
