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Old 02-04-2008, 07:09 PM   #1
beberle
Registered User
 
Join Date: Mar 2004
Location: Atlanta
Posts: 181
My Ride: 2009 328 wagon
E46 Radiator DIY

OK people. Here's my attempt at demonstrating my recent radiator DIY. Follow it at your own risk!

The Bentley's manual is very brief on this removal. Hopefully I can fill in some blanks.

I suggest the following parts if you're going to replace your radiator:
  • Behr radiator (I know it fits)
  • New hoses (don't trust old hose seals)
  • New fan thermostat (fits into lower hose)
  • 1 gallon BMW antifreeze (only use BMW)
  • New Expansion Tank (if you haven't replaced it by now)
  • New Expansion Tank Level Sensor (wanna risk a leak using the old one?)
  • New Transmission Thermostat (wish I had replaced it)
  • possibly new O-Rings for the transmission cooler
  • New Thermostat
  • New Water Pump (if it hasn't been done already)
  • New Belts (It'll never be this easy again!)

I replaced the thermostat, water pump, and expansion tank at 90k miles. I developed leaks from the radiator or radiator lower hose at 130k miles and decided to replace the rest.


1.The easiest part is removing the air filter housing. Instead of trying to pry those pesky latches open, just remove the two 10mm mounting bolt and loosen the air manifold clamp. Pull the whole thing out. Don't forget to remove the electrical plug on the MAF sensor.

2. Remove the fan and fan shroud. Don't forget the electrical connections on the passenger side of the fan shroud. The fan shroud comes off only when you have the fan off and can pull both out together. .Remember: the fan's bolt is left-handed thread (righty loosy). Even after reading Bentley's, I forgot and tightened it for 5 minutes A large crescent wrench will do the trick. I've replace my water pump before, so it was easier to get off. You may have to buy the BMW tool to stop the water pump from rotating while trying to loosen the fan bolt.

3. Drain the sucker. Depending upon the last time you drained it, it's best to drain the radiator and the engine block. I do this as step 3 because it's my least favorite part!

4. Remove the expansion tank. Note: there's an electrical connection on the bottom of the expansion tank. Disconnect this 1st so that you don't forget while yanking the tank out. There's a hose on the side and two connections at the top. Have fun getting these off! Fortunately, you're replacing everything, so you don't have to be gentle Now for the fun part.. Yank and pull for all you're worth, straight up, to get the expansion tank out. Did you forget the quick disconnect that's holding it to the Transmission Thermostat? You've probably broken the thermostat, but you don't care because you have a new one. Pull straight up until you feel it release, then push the top of the tank away from the radiator and pull the rest of the way out.

5. Remove the lower radiator hose. It came off pretty easily from the Thermostat (since I'd replace the thermostat 40k miles earlier), but the radiator connection was a bear. This proved impossible for me. What was I to do? I cut the hose of w/ a tin snips and still had just enough room to work the radiator out.

6. Remove the Transmission Cooler. There is a quick disconnect that pulls straight up. The Trans Cooler then comes straight out of the radiator (have a bucket ready for coolant). The Cooler hung fine from its hoses.

7. Remove the radiator. Bentleys says to remove the 2 big plastic plugs that hold the radiator in. I don't believe it. There was a torx screw on the top of the driver's side corner of the radiator that was securing it to the A/C & power steering radiator in front of our radiator. May be another torx screw on the passenger's corner, but mine looked to be missing. Once the torx screws are out, push the top of the radiator away from you. Lots of dirt and grit, but it will come out (and it's not attached to the A/C hoses coming into the passenger's side or the power steering hoses coming in the driver's side). Once the top of the radiator is tilted out, just pull it straight up.

8. Did you listen to me and buy new belts, water pump, thermostat? You'll never have an easier time installing these items!

9. Mount new Transmission Thermostat to the new Radiator w/ 2 torx screws. Just check out the old setup to see how it sets. I re-used my old transmission thermostat and I know I'm going to regret it! A very flimsy plastic affair. Re-use the plastic bottom piece from the old radiator for the new one. Just snaps into place.

10. Install new Radiator. It's pretty wild, but the two wedge-shaped pieces on the side of the radiator sit on two plastic 'steps' with corresponding wedges in the middle. 1st, clean these mounts. Mine had sand and dirt built up. I used an old tooth brush and cleaned it up.. Install the radiator at and angle and rest it on these ledges until you feel the wedges in the side of the radiator seat into the wedges of the mount. Now, just push the top towards the front of the car to seat it. Secure the top w/ the torx screws. Install the Transmission Cooler into the new Radiator. Hopefully you found new O-Rings. I didn't and wonder if it will leak... Note: the new Behr radiator had a new style drain plug. No need to reuse the old plug.

The rest is a cake walk...
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Last edited by beberle; 02-04-2008 at 07:14 PM.
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