s50 will not bleed

[jlevie]

If you are doing the bleed properly and still wind up with a large amount of air in the system, there is a head gasket leak (or cracked head) that is pumping air into the cooling system.

[catalyst.]

Well i swapped everything out to what was on my m50 because i knew that stuff had really low miles on it, honestly may have been less than 15~20k i cant recall.

Either way i just swapped out the thermostat for a new one and drilled a bleed hole in the new one. No luck with that.

I just attempted to bleed it again and same thing happens fill with coolant until it starts coming out the bleed hole a few bubbles come out, then i jump in the car and hold the rpms up around 2500 and i see coolant spewing out of the bleeder vent. No dice though, temp just starts creeping up on me. The block was def. filled to the brim when i changed the t stat, but the upper radiator hose has tons of air in it even after repeated bleeding.

Well if it is cracked head or popped gasket what it the best way to diagnose, i can rig a gauge with valve into the TB heater sensor hose and put 5 psi in the system then close to check leak down, will that work or should i go get a 'real' coolant sys pressure tester from advance auto (apparently they have one that fits the e36 rad)

Fred is this why you gave me that spare head? LOL

[jlevie]

The first thing to do is to fill and bleed the system correctly, which is by:

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 2000-2500rpm 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.

If the "bleed" never completes and air continues to come out, or if the system collects air after the bleed, there is a head/gasket problem.

[jalopi]

Just make sure you get the coolant 'sniffed' before you diagnose it as a bhg or cracked head.

[catalyst.]

The first thing to do is to fill and bleed the system correctly, which is by:

Thanks for the run down, Yes i have done all of this three or four times. It must be a headgasket issue. I would like to at least pressure test it and confirm for peace of mind and also i have never done a coolant sys pressure test before and i would like to get the experience.

Im thinking a leak down may also be beneficial as i mine as well rebuild the bottom end as well. Im not changing the headgasket in the car, its too finicky for me i would rather just pull it out again, besides at this point i think i could probably have it out in about 2 hours flat by myself. Air tools really make the tear down an absolute breeze

On another note the transmission while low mileage (60k) has a bad 5th gear lean with all new shifter bushings so i mine as well address that.

Pics are always good, here is the culprit





My autozone parts must have been the problem :)

[FredK]

That's some bad luck. When I had the engine in my e30 there wasn't anything weird going on with the cooling system. The pressure test will definitely narrow it down, I hope it shows no leaks!

I had a spare head for a "just in case" scenario because it's a lot easier to source a head when you don't need it than when you really need it.

[catalyst.]

Yeah i dunno im sure you would have told me if you had an issue, like I said i dont mind sending it to the machine shop. Im not 100% convinced its a HG it runs like a bat out of hell thats for sure. The main bearings looked near perfect when i put in that pickup tube bracket.

[catalyst.]

Anything else i should check, maybe heater control valve issues, i know i had a problem like that before in another car that was very hard to diagnose. The heat never really gets hot, i can feel it start to get warm but thats right before the gauges creeps up and i have to shut down

[wilholl]

I just installed an s50 in my e36 and the coolant will not bleed, ive jammed as much coolant in it as i can and it just overheats. Never had a problem bleeding these things before that i can remember. This engine was on a stand and was completely empty of fluids when i built it up.

The front of the car is elevated
Using BMW coolant
Massaging the radiator hoses as i do it

The upper radiator hose goes airbound EVERY time

Could it be a bad thermostat? i took the thermostat off of my m50 it has around 30k miles on it, looked brand new

Starting to be afraid im going to blow a f*cking headgasket here, i shut down when/before it hits the 3/4 mark everytime

catalyst. (OP), I had this same exact problem in my e36 for several months!
I could not get the air out of the system and several over heats, even ruined a good aluminum radiator.
Believe it or not I fixed this very same problem by replacing the heater control valve. The heater control valve in the e36 can fail internally and get plugged with crud then the heater system traps air and you cant get it out (there are several posts in other forums about this). The hot steam created will kill a new thermostat, by the way.
I would highly recommend replacing the thermostat if it gets an overheat condition.
Also, the best way to get coolant in an e36 and check the coolant system at the same time is to get yourself a Coolant System Vacuum Checker/Filler. Most fantastic way to fill a coolant system that I have ever seen!
By the way, all of this comes from very frustrating personal experience!!

[catalyst.]

Should i bypass the heater core/control valve to eliminate that as the problem?

Yes it is very frustrating.

What kind of pressure tester/bleeder did you use?

I am being careful about heating the car all the way up to the red mark I always shut down at the 3/4 mark I assume this is sufficient

[wilholl]

You can pull the heater control valve and look inside it. If it is clogged with gunk you can see it. You might be able to clean it all out by taking it apart. They are pricey to purchase new, way over $200. But you can pick up a used one from a junk yard or ebay. I was going through a HUGE nightmare, like you, before I found this out. It was unbelieveable that something this small could cause so many problems. I went through radiators, thermostats, waterpumps, drilling little holes everywhere to bleed air. Then I replaced the valve and no more problems.
The old one was plugged with rubber pieces, old seal material and other crud.
You can check too see if this is a possible problem by turning on the heater when the engine is hot, if the heater still blows cold air then the valve is plugged. Mine would blow hot air only if I was at high RPM, driving on the highway.

I used this system below, works amazing!
When done correctly there is no possible way to have air in the system

Is there an easy way to bypass the heater core and control valves I don't want to start throwing unnecessary parts at this thing but the fact that fred is saying he had no issues with this engine really makes me think something else is going on

Yes it is very frustrating.

What kind of pressure tests/bleeder did you use

I am being careful about heating the car all the way up to the red mark I always shut down at the 3/4 mark I assume this is sufficient

[catalyst.]

Yeah i was looking at that kit on amazon, know anywhere to buy one locally?

It is possible that the valve is seized up. I am not getting hot air, it is luke warm at best. Also the car has been sitting for three years prior to this engine swap, i have no idea if the heat was still working when i pulled the old motor.

[catalyst.]

Pressure test is loosing about 3.5 psi per half hour

[catalyst.]

Well it tested bad pretty much, but i went ahead and installed another heater control valve i had laying around (cleaned and tested it first) and still no good, overheats. The old heater control valve was clogged up on one side though.

[wilholl]

if the control valve is not plugged and your pressure test is good then you gotta bleed, bleed, bleed the air.
I had the front of the car jacked up in the air as high as it would go and revved up to 2k and let all the bubbles come out.
Still got to shut it off and let it sit and keep topping it off as the air burps out of the system, repeatedly.
I think E39's are worse, but I did find a good write up on the bleeding the e39 that helped me with my e36.
However, honestly, for me, I didn't have much luck until I tried the Vacuum tester/filler. It just made it a lot easier and I have not had a problem since.
I did order mine from Amazon. Couldn't find one local to me.