525i proper coolant bleeding method

[ShadeTreeBill]

Yep, the timing belt cover, and timing belt have to come off too. Take the TB Cover off first, and Put a wrench on the crankshaft before you remove the timing belt,and turn the crankshaft clockwise when viewed from the front of the motor. Line up the mark on the crankshaft with the notch on the motor,and line up the lines on the cam sprocket with the mark on the head.

This puts everything at top dead center.

If you have already taken off the timing belt no worries, you can line them up afterwards as well. This is critical to prevent any damage to the valves.

To make turning the motor with the wrench easier remove all the spark plugs so that you won't be fighting the compression of the cylinders.

When you put everything back together, and put on the new timing belt and tensioner, make sure these marks are lined up. To adjust the tensioner, you simply release it and let the spring provide the tension. Tighten the tensioner lock nut. Then take your wrench on the crankshaft and rotate clockwise the crankshaft two full revolutions, of course the cam shaft will be turning also. Make sure the marks are still lined up, and then release the tensioner lock nut again, and the spring will take up the final slack in the timing belt. Do not push against the tensioner to 'tighten' the timing belt. Follow this procedure to insure proper tensioning of this critical element on your engine.

Remember to degrease all gasket surfaces with brake cleaner or equivalent... I used a thin layer of high temp silicone on the intake and thermostat gaskets, but nothing on the head gasket, or exhaust manifold gaskets. I think the degreasing is critical on the head and block surfaces.

I cleaned the tops of the pistons with a wire brush on a drill motor to remove the carbon buildup, and similarly on the valve faces and seats.

I put on new V-Belts everytime I did mine. One thing that caught me off guard and took a couple of passes to figure out: the books all warn you against overtightening of the V belts, and that is important. However, you should cinch up the power steering pump belt pretty tightly. If it is even slightly loose you will have an strange intermittent power steering problem that happens mostly right after you start up the engine. The power steering will growl, squeak, and buck a bit, but then it will be OK. This will come and go, and not always happen, but will come back at the strangest times. Tighten up the belt a bit more if this happens, and it will go away forever...

Have fun... let me know how its goin'!

[atv087]

hey is there any trick to getting the coolant and oil out of the holes on the block so that i do not crack it? I have everything else put back together i just want to get that cleaned out so i can put the head on

[ShadeTreeBill]

I assume you mean the bolt holes for the head bolts..... You do want to clean those out pretty well, and make sure no liquids remain in them.. I flushed them with lots of WD40, then used long cotton swabs to soak up whatever WD40 remained down in the holes.... an alternative is the blow the the WD40 out with canned air.

You should 'clean the threads' by running a appropriate size thread tap in and out of the hole, I used one of the new head bolts for this after cleaning the holes out.

As far as the coolant oil mix that is down in the water jacket of the block, You will have to flush that crap out after everything is back together. I think that's how we got started on this thread.

After I got mine back together, I started in on the coolant bleed process, and never could get the car to run at normal temp. I kept running it up to temp, bleeding lots of coolant out of the thermostat, but what I eventually noticed was that the hose that runs from the thermostat housing down past the fan to the bottom of the radiator never got hot: There was no circulation through the radiator... it was clogged with congealed oil/coolant mix.

I took it out of the car, and set it up to drain on the pan, and about a quart of nasty crap ran out of it.... I then decided to the spend the money to get it properly cleaned at a radiator shop... $50.

You may not have this problem, my head gasket had been bad for at least two or three months, so I had lots of oil mixed in with the coolant.

I have a large plastic "tray" about 2 feet X 3 feet X 10 inches deep, and I put this under the car to catch the nasty coolant oil mix as I flushed out the engine and radiator. I eventually "processed" this stuff mixing it with bag after bag of "oil dry" (kaolin clay) and shoveling it into garbage bags to dispose of it curbside....

Hope this helps!

[atv087]

ok so far so good head is back on still waiting on bolts though. new timing belt on. It was a pain in the butt to crack those bolts on the big bulley. the spring loaded thing is about 1/4 of an inch away from the hole in the intake manifold though i dont know if it needs to be pulled up to sit in there or what. Old timing belt was full of cracks put it under my foot and yanked upwards and the thing snapped. Old tensioner was shot too.