Bleeding cooling system

[rodrigo]

Just finished replacing the timing belt, and everything is fine, except the carr is running really hot. The temp. gauge gets to 3/4 on the red side just sitting at iddle, which it didn't before. I just replaced the thermostat, and had the crank and intermediate shaft seal cover off, so most of the coolant came out of the block.

How do you guys bleed the cooling system on a 6 cyl. between the overflow resevoir and the bleeding screw on the thermostat housing? So I need to open the coolant drain plug on the block??


Here another idea of mine:
During the timing belt swap, I also replaced the thermostat. The thermostat had an 87 stamped on it, which I think may be the temperature at which it opens. What temperature thermostat do the 6 cyl's call for?

thanks.
R

[restoration]

if you are looking at the frontof the car on the left side of the engine look at the block there is a big bolt there. First drain the radiatior and overflow then undo that bolt. Have a huge pan because that shit comes out in a hurry.

[rodrigo]

if you are looking at the frontof the car on the left side of the engine look at the block there is a big bolt there. First drain the radiatior and overflow then undo that bolt. Have a huge pan because that shit comes out in a hurry.

I don't know if that answers my question. The system was drained. To replace the timing belt, I had to drain the coolant to remove the radiator. Then I also replaced the water pump, so more coolant came out. Then I pulled off the front block cover to replace the crank and intermediate shaft seals and more coolant came out from that too....so I think the system was almost completely drained.

I went and put everything back together.

When I went to refill it, I just filled up the over flow and it tool about 2 gallons of 50/50 coolant/water mix. I started the car, opened the bleeder ont he thermostat housing and only coolant/water came out so I plugged it back up.

Problem is...the car is still running way hotter than it was before...3/4 as opposed to 1/2 on the temp gauge.

[restoration]

hmm sorry thought you were asking how to drain system. did you replace hoses my car ides at half temp on the gauge at dead stop

[rodrigo]

hmm sorry thought you were asking how to drain system. did you replace hoses my car ides at half temp on the gauge at dead stop

no, the hoses are the same. at iddle, my temp gets to 3/4, and I shut it off because I don't want to do any harm. while driving, it stays between 1/2 and 3/4.

[Easily Distracted]

Keep checking with the bleed screw after it has heated up and you have reved it. Once the thermostat has opened, it will release any air tapped behind it. Revving it will help dislodge air trapped along the way. A drop in the resivior is a givaway that you dislodged an air bubble. Turn your heat on, too and make sure your heater core is blowing hot. That should tell you if the thermostat is sticking.

For my '87 325i thermostat, I think the stock temp is 80deg. BavAuto also makes ones that open up at 71 and 75deg for warmer climates.

[jlevie]

The way to bleed a BMW engine is to:

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

[rodrigo]

thanks!
so far its working...the operating tmep is approximating mid-gauge.
I'll try again tomorrow and see if i can bleed it out some more.
:)