Head Troubles

Hi. I've got exactly the same engine as you, which I have recently rebuilt due to crankshaft wear. I can only suggest that you change the timing belt tensioner wheel too for peace of mind, and make sure there are no vacuum leaks anywhere, making sure you really seal the rocker cover gasket well. If not you'll end up with a lumpy idle. Also you really need to bleed the cooling system thoroughly as you'll end up with a temp gauge in the red and no heaters (ask me how I know!!!). Hope this helps!

Cheers,

Shaun

Bleeding the system was a pain when I put my engine back together. I only managed to bleed it thoroughly using a "unique" method since nothing else worked! Do not follow this unless you are 100% confident - antifreeze is poisonous!
      First off drill a small hole in your thermostat and make sure the hole is upright (12 o'clock). This helps get the air out quicker. Seal the thermostat housing up thoroughly afterwards. Fill your system up as best you can with mixed coolant until it it at the MAX mark on the radiator expansion tank. Jack the front of the car up to help the air bubbles escpe. Run the engine to warm it up a bit. Now the controversial part!! Loosen the small bolt on the thermostat housing, and wipe the top of the expansion tank hole with a damp rag because you need to BLOW the coolant down the tank (pressurising the system). You may get hot coolant coming through the 'stat bleeding bolt so be careful. Keep topping up regularly, as you don't want to put more air in the system. Also keep an eye on the temperature guage as you don't want to fry your head! After about 10 minutes you should fell all 3 hoses to the heater matrix getting hot ( make sure your heater temp controls are turned fully clockwise). You may need to rev the engine occasionally to help the coolant go round. By now the big hose from the thermostat housing should be warming up, so you know the 'stat is open. Keep blowing, revving and topping up until you have a regular stream of coolant coming out the 'stat bleeder. Now tighten the bleeder and slacken the bleeder on the top of the radiator. Start blowing & revving again until the coolant flows out of the bleeder. Tighten the bleeder back up. Now ALL hoses round the engine/heater valves/matrix should be hot - if not you still have air trapped somewhere. Repeat all the above until there is no cold pipes and the heaters blow hot air & refit the filler cap.
I know this method will raise a few eyebrows but after fitting 2 head gaskets, a new rad/stat/heater matrix/viscous coupling etc I figured this was getting expensive and desperate measures were called for! I can bleed my system in about half an hour using this method. My temp guage sits at 1/2 way when warmed up. Please be careful putting your mouth over the filler hole when you are blowing the coolant down - if in doubt don't do it - wouldn't want to see you poison yourself! Take the car to a BMW dealer who will be well capable of bleeding the system. Maybe someone else on the forum knows a safer way of pressurising the system.

Best of luck!

ShaunJavaScript:AddSmileyIcon('%5B:biggrin:%5D')