BimmerFest BMW Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I had plugged cats on my 2004 BMW X3 and when driving home from work it started making a nice exhaust leak sound. Went ahead and replaced the cats and noticed the sound is still there. The sound is coming from the back of the engine and out of the hole (see picture) does anyone know what that is?
Automotive tire Motor vehicle Automotive lighting Wheel Automotive design


thanks!
 

·
Registered
Joined
·
3,143 Posts
That's a freeze plug. Blown out due to back pressure?
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
That's a freeze plug. Blown out due to back pressure?
Thanks for the quick reply. It definitely blew because of pack pressure. I have tried to remedy everything to fix the error codes and have always hated this car because it has been so slow and sluggish but with the new cats it a whole different car.
Do you know why exhaust would be coming out of the freeze plug? Can I tap a new freeze plug in?
 

·
Registered
Joined
·
3,143 Posts
They are wedged in, not threaded. The holes are needed for casting the part, so apparently that one does not go into the cooling jacket, but instead an exhaust port?

Finding the correct size and material can be challenging. OEM if available is best. If not, auto part stores should have a sorted box of them; remove and bring in the old one. Steel or brass, typically; IDK what BMW uses though.

I always coat the outer part of the new plug, where it mates with the head/block/..., with a thin layer of Permatex #2. Install with a socket that is just smaller, to fit inside the dish. Then tap, squarely, with a hammer. Not too deeply; just to where the edge of the new plug is below the surface of the head/block/...
 
1 - 6 of 6 Posts
Top