Overheating Disaster

[sgt. pepper]

As a last ditch effort, I come to thee, fellow Bimmerheads, in hopes of solving this conundrum.

It all started when I swapped out all the belts and water pump last September. I wasn't able to bleed the system easily because the bleeder screw was stripped so that was a headache. I eventually got it running at an optimal temperature and took it to H20i last year with no problems.

That was over a year ago and I've only put 6k on the car since. I started having issues with starting and traced it to the alternator so that was quickly replaced, and upon pulling up to my friend's garage to do so...my bypass hose blew and spilled like a skunt. I noticed I would occasionally have creeping temps at idle over the previous months so I had begun questioning the thermostat.

I tried swapping the old one out but the bolts holding the cover of the thermostat housing snapped so I ordered a new housing. I also replaced the bypass hose, THREE TIMES! The first one was too long and hit the mechanical fan, so I cut it only to find it leaked. The second one came in already ripped. The third was fine, and then a tiny pin sized hole blew out of the top of my new thermostat housing. Careful use of JB Weld took care of that and this is where I stand:

The car, no matter how much I try to bleed out the coolant system, still overheats. The head gasket doesn't seem to be blown, the thermostat is new, hoses are good, radiator was fine and got cleaned out when I did the water pump, and I am bleeding it properly. I never let it get too hot to the point where I'd imagine the head gasket would blow but I am stumped.

I just realized my electrical fan, the one behind the grille, isn't spinning. I don't know if this could cause my disastrous dilemma but I am drawing blanks at this point. The radiator fan spins properly and the top hose is hot and allows coolant to flow. I am getting a ton of steam coming through the bleeder but I realized fuse #19 (7.5amps) was blown. I figured that'd kick the fan back on but it's still not spinning after replacing it. I also noticed, upon removing the grille, that I could pull the fan off. I'd imagine it's supposed to be held in place by hardware, amirite?? This fan won't kick on when I push in the AC snowflake, which I read will usually do the trick.

Also: the heat isn't kicking on. Hasn't consistently in a while.

WHAT COULD IT BE?!?!

[canakami]

Creeping temp at idle: Bad Fan Clutch
Hose bursting off: Possible over-pressurization from leaking head gasket.
No heat: Clogged heater core/coolant passages.
AC Fan: IDK

[Cronopoulos]

.....I am getting a ton of steam coming through the bleeder

Rent a compression tester and see what it shows.

[sgt. pepper]

Creeping temp at idle: Bad Fan Clutch
Hose bursting off: Possible over-pressurization from leaking head gasket.
No heat: Clogged heater core/coolant passages.
AC Fan: IDK

I'll check the rest but that hose that blew off moreso just ripped after the clamp, it was old and had been cut at some point instead of being replaced. I hope I don't have to do anything with the head gasket but I'll look into that if I can't get it bled tonight. Who knows how long the AC fan hasn't been working, the AC hasn't worked properly since I got the car and I'm just now noticing that the fan doesn't spin.

[sgt. pepper]

Got it bled! WTF?! After trying on and off for a month....While I'm driving it sits a click before half and idling it never jumps past the 1/2 mark. Now I need a battery or a starter but she's good to go and terrorize old women again. Thanks y'all

[K1CKBAC]

What did you do different this time to bleed it? I got a similar issue.

[semaj4712]

Bleeding the coolant systems a pretty easy thing, what did you do wrong?

[K1CKBAC]

Not sure if I still have air in the system. Just eliminating the possibility before I start spending money. It is probably my fan clutch at this point.

[jlevie]

The overheating and lack of heat could be air in the cooling system. That air could be from a failure to fully bleed the system, or it could be from a small head gasket leak that is pumping air into the cooling system. One simple DIY check for a head gasket leak is to fully bleed the system, drive the car for a bit, and re-bleed. Release of a significant amount of air on a re-bleed is evidence of a head gasket leak. Another is to release any pressure on the cooling system with the engine cold. The drive the car for a bit and allow the engine to completely cool down. If the hoses are hard pressure has built up in the cooling system from a head gasket leak.

Bleed the system 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.