[Bimmer_Engineer]

Does any one know if the coolant bleed cycle subjects the coolant system to the same pressures as if the engine was running? I’m asking because I found that the tranny cooler was leaking fluid while I was changing out my serpentine belt. I pulled the connection that was leaking and it’s not cracked and it doesn’t have an o ring in it (nor should it according to realoem). So I put it back on and dried off the cooler and ran a bleed cycle...the cooler seems to be dry after the cycle. So I’m wondering if that simulates actually running the engine before I put the radiator fan back in and put the car back on the ground...

[nissubaru]

I don't have an exact answer for you, but think about this for a second. When you heat up water, you increase the pressure in the system. I'd assume that running the water pump bleed cycle doesn't simulate the pressure placed on the cooling system at operating temp.

Just my thought on the matter. I'd say i'm 100% certain about that on other cars but on the BMW I could be dead ass wrong. On my other cars I have a coolant recovery/coolant overflow tank that fills up with coolant whenever the pressure exceeds the max PSI on the radiator cap. It flows through to the overflow tank where it sits until the system cools/depressurizes enough at which point it sucks the coolant back into the system. The BMW may work the same way but the overflow tank and the coolant reservoir are the same on these cars as far as I can tell. Not sure how it regulates pressure to be honest.

[feuer]

How can it simulate engine running? Absolutely not! Just moves coolant around to make sure system is free of air pockets. Pressure is ambient. Fix you transmission cooler leak.

[kfrazie1]

Originally Posted by Bimmer_Engineer

Does any one know if the coolant bleed cycle subjects the coolant system to the same pressures as if the engine was running? I’m asking because I found that the tranny cooler was leaking fluid while I was changing out my serpentine belt. I pulled the connection that was leaking and it’s not cracked and it doesn’t have an o ring in it (nor should it according to realoem). So I put it back on and dried off the cooler and ran a bleed cycle...the cooler seems to be dry after the cycle. So I’m wondering if that simulates actually running the engine before I put the radiator fan back in and put the car back on the ground...

You sure there’s no oring there? Also make sure it is fully seated.

[Bimmer_Engineer]

Originally Posted by kfrazie1

You sure there’s no oring there? Also make sure it is fully seated.

Where the hose connects to the cooler there was no o ring when I unseated the connection and real oem doesn’t show one there either. I know it’s fully seated now and it seems to not leak right now but I can’t start the car. Like I said the fitting isn’t cracked and there’s no o ring in there so I don’t really see what could leak in the first place. I’m considering just putting it back together and checking leaks as I’ve got to wait a week for a new hose if I order one...

[feuer]

Why you can't start the engine?

[Bimmer_Engineer]

Originally Posted by feuer

Why you can't start the engine?

Right now I can’t because I haven’t put the radiator fan back in yet...I’m going to do that this morning...

[feuer]

Originally Posted by Bimmer_Engineer

Right now I can’t because I haven’t put the radiator fan back in yet...I’m going to do that this morning...

That should not prevent you from starting the engine. Why would you put parts back only to remove them later to fix the transmission cooler leak?