Pressure cap diagnosis
I've been having overheat issues that are symptomatic of air in the system/air locks with the temps normal for a while than a sudden spike. Had it diagnosed locally at a shop with diesel and rover experience, and they said it just needed to be burped more. Have gone through air bleed cycles several times and had another major over heat. Everytime i think this system has been filled finally , I'll end up a day or two later with another overheat (and immediate pullover-rest). After each overheat, then next day after a full cooldown, the radiator tank it low and the expansion tank is high.
shop confirmed t-stat was working fine and said they don't think there's an issue with the headgasket as no gas has been observed in the coolant with engine running.
After longer runs where the engine gets good an warm, when I stop the engine and get out, I can hear a slight hissing from the expansion tank and sometimes the pressure cap will purge some fluid.
I just replaced the pressure cap with a new one, and will test drive it tomorrow. But for a properly operating 300 tdi, how do you know when the system has been bled properly? For a completely bled system, would the t-stat fill plug always be completely full when removed cold, or would there be some air in it?
My understanding is that the fill line in the expansion tank is the same level as the radiator fill plug. What would cause the radiator level to drop and the expansion tank level to rise?
Also, if my old pressure cap didn't seal well on the threads under pressure, what would be the symptoms observed from that?
I'm starting to lose confidence in this 2.8 engine. It's been a run of trouble.
ISIL and al qaeda can go F*ck themselves...