525i proper coolant bleeding method

i have a 1990 525i it needs the cooling system bled. i do not have a bleeder cap on the expantion take it snapped off some time back but i have the bleeder ontop of the thermostat and all that comes out of it ever is steam

any ideas

There should be like a blueish drain plug on the bottom of the radiator if not you can always wait for it to cool and just take off the bottom hose.

i dont need to change the coolant i just need to bleed out the air in the system.

i open the bleed valve n all that comes out is steam ive tried for about 4 days now and icannot get it to work

You say the radiator bleed screw is broken off? It should be a brass screw on top left side near the expansion tank, but on the radiator body itself.

Bleeding the cooling system is a real pain until you figure it out, which took me about three or four times of having to bleed it.

There are numerous sites on the web that speak to coolant replacement and bleeding the system. They all say to turn the heater controls to full hot position. Do that.

What works for me is to take the brass screw out of the top of the radiator, and open the bleed screw on the thermostat. Start pouring the coolant mix into the expansion tank, and here it the important part: USE A FUNNEL so that you can fill it above the neck line of the tank. Fill the funnel cone, and it will slowly offset the tank contents to add more to the radiator, and keep adding until it comes out the thermostat bleed screw port.

Close the thermostat bleed screw, and continue to add more coolant to the funnel until coolant comes out the top hole on the radiator: where the brass screw is.... If you brass bleed screw on top of the radiator is broken, then I would expect that you have a leak there.... You may need to get the broken screw out and replace it with a new screw. The alternative is a new radiator which is costly.

Crank the engine and run it until the thermstat opens. (You did install a new thermostat, right?). Usually this is when the temp gauge reaches 12 noon postion. Stand back, and crack open the thermostat bleeder screw just enough that coolant and air bubbles start to spurt out. Put a catch basin under the vehicle to catch the poisonous coolant....

Check the top hose that leaves the thermostat to see if it is getting hot. The one that goes down by the fan to the bottom of the radiator. If the car is HOT but this hose is NOT, then your radiator is clogged. Take it to a radiator shop for cleaning, or buy a new one.

After bleeding hot coolant and air out of the thermostat for a while, Close the Bleeder: cut off the car, let it cool completely. Add more coolant, and repeat this cycle. You should only have to do this about one time.... maybe. You know you are done when you meet two conditions: The car does not overheat: Temp Gauge reads 12Noon, and the heater gets hot: air bubbles are gone from the heater circuit.

The first time I broke open my cooling system, it took me three days get the cooling system to work.... what a pain!

Good Luck!

well the car is sitting here until this weekend im doing the headgasket and a few other things while i have 2 extra cars to drive. I figure ill drain the coolant and oil because its starting to have a bad oil leak right at the headgasket etc so im going to pull everything apart sometime this week and this weekend do the whole gasket job. If anyone has any tips on that please let me know. Thanks

I did the headgasket on mine two times: the first time when the timing belt broke,and I had to replace the head due to damaged valves, and cracked castting....

ABout a year later I had to do the head gasket again since it had started leaking.... the only reason I could figure out was that I did not use a 'degreaser' on the head and block surfaces before reassembling. I used a new good quality gasket, new headbolts, and followed the torque procedure to a T, but it "blew" about a year later.

The second time I took it apart (last January) I was careful to degrease both surfaces using brake cleaner, and made sure no drops of oil contaminated the joining surfaces.

Other than that, make sure to torque the head bolts, and the nuts on the intake and exhaust manifolds properly. I used an entire "gasket kit" that supplied all needed gaskets.

Last time I also replaced the exhaust manifold to tailpipe gaskets since I had an exhause leak there. The hardest part of that was getting the old nuts off. Use a lot of penetrating oil, and patience....

That's all I can think of at the moment... have fun!

hey bill do you happen to have the torque specifications?

Well... there is a torque spec for virtually every nut and bolt that you will remove in the process.

If you do not have one, you should definitely buy at least the $15 Haynes book, the Bentley book is even better but the Haynes book will give you all the torque specs and other valuable info about the process....

Briefly though: Intake manifold to head : 22 to 24 ft lbs

Torx style Head Bolts: 22 ft lbs, then rotate an additional 90 degrees, then turn another additonal 90 degrees

Exhaust manifold: 16 to 18 ft lbs.

There are other head bolt styles : Hex

I don't know what you have... Best to pick up a book.

Disclaimer: use info I supply at your own risk, see definition below!

Good luck, and have fun!

headbolts on mine have 6 points looks like i can stick an 11mm socket on it to remove? all the parts came today took off the throttle body and valve cover now to tackle the head.

If they are hex head bolts yes.... the surfaces between the points are flat.

If they look like stars, then they are the torx head bolts, and you must use a torx socket. I got a set of 5 at Advance Auto... not expensive.

You cannot reuse the head bolts in either case, they are "Stretch type" bolts that must be replaced each time they are removed....

luckily i looked at the timing belt while i still have everything apart waiting for new head bolts i like to get everything before i get it all apart and realised im fucked i need all this shit i should have replaced. But the timing belt had a huge crack down the middle of it and the cap and rotor and bently manual are coming monday so everything should be good to go on tuesday

Yeah, I was just thinking that I should warn you about the timing belt.

And I hate to mention these items, but I would strongly suggest you replace the timing belt tensioner ( I had to "go back in" on mine about a month after to do this) and most folks also suggest you go ahead and do the water pump while you are in there. I happened to know that mine was only a year and half old so I didn't do the water pump, thought I am still nervous about it....

The timing belt tensioner was only about $25 from alleurasianparts.com. Mine started squealing like a banshee about a month after I did the head the first time.

Let me know how it goes!

i have the whole timing kit belt and tensioner. Now to remove the head do i have to pull the timing cover off and take the tension off the belt? i got the exhaust off the head and the only thing that feels like its holding it is the timing belt

water pump is only a month old so i know thats good i got a new cap rotor and coil while i was at it along with a new thermostat and a good oil filter good oil and bmw coolant. hopefully all goes well btw bill thanks for your help

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'!

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

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!

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.