Sudden But Intermittent Coolant Loss

[Fless]

My '94 X Eddie Bauer (124K miles, A4LD) experiences intermittent coolant loss. The coolant level stays the same in the overflow reservoir for several months, then all of a sudden it's gone. No external leaks; I see no antifreeze in oil, no oil in antifreeze. I have an unrelated CEL code 214, but no others.

I thought I saw a thread on this a while back but can't seem to find it. Any ideas or suggestions?

 

[Gadget X]

Maybe a poorly fitting cap? Does it randomly run hot from time to time? If so, it could have bad thermostat, which "sticks" occasionally, causing an overflow, which would cause your unexpected coolant loss.

 

[Fless]

Never runs hot; I put a new 195 deg. thermostat in it at about 110K -- the old one was stuck open -- and once it warms up it varies little on the gauge (usually on the "R", but on a hot day going uphill in the mountains, top of the "M").

No sign that the overflow bottle has overflowed.

I'll try a new cap.

 

[Gadget X]

Good luck, and keep us posted!

 

[vq5speed]

How do you know its all sudden empty. You check it daily for months then one day is full then the next day its empty..

 

[Fless]

I don't drive it all that much (not primary transportation) and my mild OCD requires me to check it often, if not before every time I drive it. And sometimes right after. <grin>

 

[FR-425]

Water evaporates. Even when mixed with anti freeze.

Coolant loss over several months is normal.

Take the OCD blue pill, or orange one, can't remember which one right now, oh look shiny.. .. .

 

[Fless]

Agreed, but not this suddenly. One or two short trips, less than 100 miles total.

 

[FR-425]

Usually leaks that only occur while running and leave no drips on the ground after stopping are from the radiator tanks.

The fan sucks it up and turns it into a mist and it evaporates.

The leak is only while the system is under pressure and to small to drip after shutdown.

If you pull the fan and shroud off you will see the green goop.

Same scenario if it is leaking onto the intake and boiling off. Again you will have build up on the manifold if this is happening. Usual spots, temp senders, heater hoses.

Either way just getting the intake tube, fan and shroud off will give you the room to get in there and have a close look.