Hi. I am experiencing a perplexing situation with my '93 940T (217,000 miles). I recently purchased this car and had issues with the coolant system. I seem to be losing coolant somewhere..., but I am not seeing evidence of it leaking anywhere; such as through hoses, expansion tank or the water pump.Nothing wet under the car either. I have replaced the tank,cap and water pump very recently. When the system is hot the expansion tank will be at just above "MIN" one minute and then empty the next. (When the car cools down, I can loosen the tank cap, and coolant rushes back in to about the original line.) The radiator hoses will be VERY hard. I am not sure if the system is circulating or not. So far no overheating. The heat inside is very good. I don't drive the car far or at all. Thanks.

 

First, eliminate possible head gasket problem by taking a compression/leak down test. If you are getting heat then circulation is fine.

 

To continue with my symptoms. I have recently notice a film of what looks like oil inside the new expansion tank. I have changed the thermostat and upper rad. hose this weekend, and also the oil breather box. I can feel the thermostat open and coolant flowing. After the system heats up, the rad. hoses still get hard, but not as hard as previous. During testing static in my yard I can still notice that coolant is disappearing in the expansion tank, but comes back after I loosen the tank cap. Good heat in the cabin and NO overheating issue. I am wondering what might cause this; head gasket, blockage, or possibly a issue with the turbocharger(oil/coolant lines). Still don't dare to drive the car for fear of doing major damage. HELP! Thanks.

 

Well, again, CHECK THE HEAD GASKET! Do the test!

 

You can also pull the spark plugs. If you have a suffient leak in one cylinder, you'll find a very clean, white plug as the water does a good job cleaning it.