Cooling system pressure ?

[TUD]

The car has had the thermostat replaced, temp sensor, coolant sensor, coolant tank w/ new cap and level sensor.


Took a quick spin, got home noticed that some coolant was burning. It looks like the new Rad. Cap maybe a bad one compared to the old one. Car did not over heat, was under the middle mark the entire time (even since the new thermostat it rarely reaches the mid-mark). Hoses have no pressure now even after I bled the system several times per the instructions on BMWE34.net (M20). I put the old cap back on and took a spin. It appears to did not leak any more coolant, but the system has no pressure. Any ideas why the hoses are not firm especial at normal operating temps????

[AdamF 88iS]

Does the car use coolant over time? If you dont see a leak but it slowly looses coolant you may be loosing it into the motor via a cracked head.

[TUD]

Does the car use coolant over time? If you dont see a leak but it slowly looses coolant you may be loosing it into the motor via a cracked head.

I should have mentioned that it had pressure prior to the new cap coming half ways off today (doesn't apprear to fit correctly). I do believe the new cap is defective. With the old cap it does appear to have pressure. We'll see if it last after I exchange the cap for another one.

[AdamF 88iS]

Well then yea, the new cap is probably defective.