mysterious coolant leak

[NameIsStanley]

I recently replaced all the coolant hoses with a silicone set and now I have a coolant leak on the passenger side. I can't pinpoint the source. I double checked all the connections and they're all tight. It also doesn't seem to leak when the car is just idling. It's only after driving that I notice the leak. It's dripping from the control arm bushing/bracket and the tiny square hole that is ~3" aft of the bracket. It seems like it's seeping through the frame rail. Any ideas?

[Dave @nz]

Hi
The overflow hose from the coolant tank goes in to the frame rail and drips out the bottom of the chassi rail.

[NameIsStanley]

Hi
The overflow hose from the coolant tank goes in to the frame rail and drips out the bottom of the chassi rail.

Thanks. That must be it. I did a quick search. It looks like coolant should not be dripping and the most likely cause is a bad cap?

[stevesingo]

Yep, Bad cap.

[BMG]

Off topic, but what is that bracket on the chassis rail for ?

[Todd black 88]

Lifting the shell during manufacturing is what I was told

[L James]

I always thought it was for securing the car with a hook when flat bedding... Hmmm... Learned something new...

[BMG]

Lifting the shell during manufacturing is what I was told

Never seen it on an E30 before and mine doesn't have it. I thought it was someones add on, but it looks like the underseal is applied over it making it look factory.

[1990m3]

That hook is on all 3 of my m3s

[bMar]

Guys, I’ve been topping off my coolant for too long now. I know it is coming out of the coolant tank overflow hose, I’ve collected it in a bottle while driving. I’ve had three different caps installed an this problem persitsts. Could there be another problem that causes higher pressure that normal to leak this coolant out past the cap? This is driving me nuts.

[jwbavalon]

Hi, I had problems with "off the shelf" rad caps and so went back to a BMW OEM rad cap and the overflow stopped. I don't think it is too much pressure but rather a rad cap problem.

Happy New Year