Radiator elbow leak
 

I had a very slow leak at the elbow at the top of the radiator on my 88 300 SEL. I thought I'd preempt disaster by replacing the elbow as I'd seen others on the forum do. It was a simple job, there was some corrosion on the old one and absolutely no gasket left. I thought I was done. Unfortunately, I am getting a leak from the exact same place now. I'm sure it is coming from the elbow as I can see the liquid in between the seams. Is there anything I could have done wrong? All I did was pull out the old one and pop the new elbow on. My new one now leaks slightly more than the old corroded one. Am I supposed to put some sort of liquid gasket on the elbow before I put it in?

This isn't mine, but it's exactly where mine is leaking from.

There should be an O ring on the elbow, right?

You can also try to put a clamp in the horizontal direction to squeeze the "socket" against the elbow a bit. I twisted a steel wire to tighten that a bit.

The elbow is clipped on the radiator, it is visible on the picture.

Try to separate it gently (avoid beakage of plastic) for the presence of an O-ring.

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