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Old 11-03-2012, 10:07 PM
bmw4ed bmw4ed is offline
Ed's E36 in SoCal
Location: Irvine, CA
Join Date: Oct 2012
Posts: 18
Mein Auto: 1997 328i E36

THe screwdriver in the photo points to the problem area. THe radiator overflow tube nipple is way too short, and it has no barb to keep the tube from falling off with heat and pressure.

A shop had replaced the radiator in my sister's car. I don't know if this problem existed all along. After a year, I noticed the overflow tube area was wet. I removed the tube from the radiator tank and noticed the nipple is too short (only about 1/4-inch long, and no barb to keep the clamped tube from falling off). I clamped it tightly, but during a long trip the tube fell off and I had to pull over and make a quick fix.

In the photo, you see how I added an extra length of tube, clamped the tube to the very short nipple, and clamped the tube to the radiator large outlet hose clamp (to apply a constant force which kept the overflow tube from falling off for the remaining 400 miles of the trip).

I want to make this a permanent repair. I found overflow nipple repair kits for BMW and MBZ cars that tell you to tap a hole in the tank and install a metal barbed fitting. Some say this repair won't last b/c the metal and plastic tank have different thermal expansion rates and the repair eventually works itself loose. Also, I don't see a kit for my 1997 E36 328i.

Someone said they used a mag-wheel-style tire stem and inserted it from inside the radiator tank, and tightened the nut down from the outside. Mag style tire stems have a nut and rubber grommets to seal from both sides of the radiator tank. Bicycle valve stems come in smaller diameters, but I'm not sure if I have clearance inside my radiator tank to install a tire stem from the inside of the tank. I'm also not sure what to do with the threaded part of the tire stem. Plus, a normal car tire stem is too big a diameter for the overflow tube.

Anyone tried the metal BMW overflow tube nipple repair kit? Results good or bad? Do these repair kits come with a plastic barbed fitting, for a closer thermal expansion to the plastic radiator tank?

Anyone have other ideas, besides replacing the radiator. They're not expensive, nor hard to replace, but mine is fine other than the overflow tube nipple is too short.
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