[minifridge1138]

Hello everyone,

My car: 2007 E90 335i 6MT. 120K miles.

My story thus far...
So the plastic coupling between the cylinder head and the thermostat (I think) broke. This guy, but the oem plastic one: https://www.ecstuning.com/b-ecs-part...024797ecs01~a/
Luckily the tow truck driver was nice.

While replacing that hose, I broke the "nipple" on the upper radiator hose that connects the coolant line that runs to the expansion tank. So I replaced the upper radiator hose.

Now, when the car gets warmed up I have steam coming from in front of the radiator. It comes out of the grill and over the top of the radiator and out of the 90 degree elbow duct that is supposed let air flow to the intake. I don't see any smoke coming from the "back" of the radiator where the upper or lower hoses connect.

Is there anything in front of the radiator that could be leaking under pressure or is my problem the radiator? My guess is that when I was working to get the upper radiator hose on, the plastic expansion tank cracked.

Thanks in advance!

[feuer]

Maybe is residual coolant from previous leak burning off? Or another leak? Wash nicely the radiator and then pressure test and check for leaks.

[arkie6]

Originally Posted by minifridge1138

Hello everyone,

My car: 2007 E90 335i 6MT. 120K miles.

My story thus far...
So the plastic coupling between the cylinder head and the thermostat (I think) broke. This guy, but the oem plastic one: https://www.ecstuning.com/b-ecs-part...024797ecs01~a/
Luckily the tow truck driver was nice.

While replacing that hose, I broke the "nipple" on the upper radiator hose that connects the coolant line that runs to the expansion tank. So I replaced the upper radiator hose.

Now, when the car gets warmed up I have steam coming from in front of the radiator. It comes out of the grill and over the top of the radiator and out of the 90 degree elbow duct that is supposed let air flow to the intake. I don't see any smoke coming from the "back" of the radiator where the upper or lower hoses connect.

Is there anything in front of the radiator that could be leaking under pressure or is my problem the radiator? My guess is that when I was working to get the upper radiator hose on, the plastic expansion tank cracked.

Thanks in advance!

You probably broke or cracked the rigid part of the hose that runs along the top of the radiator from the upper coolant hose nipple to the expansion tank. That overflow hose has rubber hose on both ends, but the middle is a rigid tube and it becomes brittle with age and heat and commonly breaks/cracks where it is clipped to the top of the radiator. Remove the air intake duct above the radiator and you will likely see the problem.

[minifridge1138]

Originally Posted by arkie6

You probably broke or cracked the rigid part of the hose that runs along the top of the radiator from the upper coolant hose nipple to the expansion tank. That overflow hose has rubber hose on both ends, but the middle is a rigid tube and it becomes brittle with age and heat and commonly breaks/cracks where it is clipped to the top of the radiator. Remove the air intake duct above the radiator and you will likely see the problem.

That’s a good thought, but I forgot to mention that while I was troubleshooting, I pulled the fan out and watched the steam come from the front of the radiator.

The rigid hose isn’t leaking. I really hoped it was.

[minifridge1138]

Ordered a new radiator and a new lower radiator hose.

Hopefully that will fix it.

Thanks!

[minifridge1138]

After much drama, the new radiator (and lower radiator hose since I was already there) are working great.

It really felt like everything I touched broke.

Good luck!

End result I replaced the following:
Cylinder head to thermostat hose because the Mickey Mouse coupling broke.
Upper radiator hose.
Lower radiator hose.
Radiator.
Radiator drain plug <-- new radiator didn't come with one and I broke the old one.

I also flushed the system twice. Neither time was intentional.