Green O-Ring, 8x3mm - E46, E90, E39, E60, X3, X5, X6

Obnoxious coolant leak from your lower radiator hose? It's likely coming from the small o-ring on the coolant temperature sensor. Over time, and especially with removal & reinstallation, rubber o-rings harden and shrink and they no longer seal as well as original. This green o-ring is the same size as the o-ring on the coolant temp sensor, part #13621433077. You don't have to buy a more expensive sensor just to replace the o-ring (although a new sensor wouldn't hurt).

This is a new Genuine BMW green sensor o-ring. Why Genuine BMW? Because we think an extra $1-$2 is not too much to spend for superior quality in a critical area. The last thing you want to do is have to do the job over again because of a cheap-o part.