Cooling system help!

[juliea]

Sorry for another cooling system post...however, I've read through a bunch of others and am still not sure what I should do.

Here's the complete history of the cooling problems with my 91 318is:

1. Noticed that my heat was intermittent. Would have heat when driving fast, with engine rpm's above 2000 for a while. Would not have heat while not moving fast.

2. Car overheated when stopped in traffic & idling. Radiator hoses were not hot.

3. Thought thermostat was faulty, so I drained the coolant to replace tstat. Planned on flushing system with an engine flush solution while I was doing work on it, so I filled the radiator with the solution and water. Replaced thermostat housing without thermostat in place, and started car. Had heat on full hot and fan on 4. I did not bleed the system.

4. Car temp gauge still rose above normal. Radiator hoses did not get hot. No heat in passenger compartment. Tested fan with a small piece of cardboard, and cardboard was able to stop the fan. Haven't noticed any leaks.

So, here's what I'm wondering now:

1. Should I bleed the system? Would air in the system account for the problems that I'm having?

2. Could my water pump be broken, and that's why fluid isn't circulating?

3. Could my fan clutch be faulty?

4. Could the problem be something else entirely? Pressure loss due to leak...head gasket...etc.

4. Is it OK to leave the flush solution/water mix in there for a few days? I'm concerned about the chemicals within the solution, and also freezing. I live in Seattle, so temps can drop below freezing at night.

Any help would be appreciated. This is my first DIY repair project, and I'm feeling a bit confused :-/

[nomad]

air in block or a blockage in the radiator...
Take out your rad and see if you get good flow through it. Try taking off the rear drain plug from the bloc and see if it drains. Mine was all blocked up.

[xwill112x]

your system is air locked.

just warm it up, turn your heat on, with the fan 4.

have someone setting in the drivers seat checking your temp making sure it doesnt over heat (you can do it by your self, this just makes it easier )

unscrew the bleed screw about half way, its on top of your radiator.

and rev to 2500-3000 while the bleed screw is open, make sure its not over heating.

just do that till no air comes out, then screw the screw back in while maintaining revs.

it may take 25-30 mins to do properly.

that is, if you have a thermostat put back in...you didnt mention putting it back in..



you'll know when its done right when your heat is blowing warm at a sit still.

that should be all you need to know, just did this to mine after deleting the tb heater plate last weekend.

[KenC]

When you're heating it up, keep the TEMP on full hot, but keep the fan off.  If the temp is on high, you'll be circulating coolant through the heater core.  But keep the fan off so you're not blowing that hot air off of it and cooling down the antifreeze.

[juliea]

Thanks! I will put the stat back in (you're right, I hadn't put it back in, or bled the system) and try this.

[xwill112x]

When you're heating it up, keep the TEMP on full hot, but keep the fan off.  If the temp is on high, you'll be circulating coolant through the heater core.  But keep the fan off so you're not blowing that hot air off of it and cooling down the antifreeze.

if you dont have the heat on, it WILL over heat...you want it to cool the antifreeze down some, if the car is having overheating issue's already, why make them worse?

[KenC]

if you dont have the heat on, it WILL over heat...you want it to cool the antifreeze down some, if the car is having overheating issue's already, why make them worse?

The thermostat is never going to open if you're blowing all of the hot air off of the heatercore.  Without it open, you can't bleed all of the airbubbles out.

[juliea]

Is it possible to bleed without the thermostat in place? I had originally taken it out just to see if coolant would flow to the radiator without it (it didn't, as evidenced by the fact that the hoses never got hot, but my engine did).

[juliea]

Sorry, another question. The arrow on the thermostat points up, at 12 o'clock right? I'm pretty sure my old thermostat was not in this orientation. From what I've been reading, though, it seems like the arrow should point straight up.

[Boosted E30]

yes the arrow points straight up when you put the t-stat in. once you have it in take the bleed screw right out of the rad and fill with coolant slowly until full. then start your car with heater set to full hot and fan on spd 3 or 4 and just let you car warm up by it self. you can rev the engine if needed to circulate the coolant 2000-2500rpm is enough. keep and eye on engine temp and top up coolant as necissary. the trick to bleeding the system is to do it nice and slow with engine at idle and rad cap off so air can get out. if the temp starts to go above normal and you have no heat then bring up engine rpms to circulate coolant and drop engine temp. it does take a while to get all the air out so be patient with it dont rush it. once you have heat and engine temp is close to normal you can put the rad cap and bleeder screw back on and you should be ok. if the temp starts to climb again just crack the rad cap open to let out some pressure or air that may have been in the system still.

[juliea]

Thanks for all the help! Things are working great now...needle stable and hot heat! Hooray! I'm glad it was so simple and that I didn't buy a new water pump that I didn't need.

[CCR Engineering]

I've gotten it to work better by lifting the front of the car.  I just lift the front on my lift while the back stays on the ground, tends to work the air out faster.

[xwill112x]

I've gotten it to work better by lifting the front of the car.  I just lift the front on my lift while the back stays on the ground, tends to work the air out faster.

or you can repeativly sqwease the top radiator hose, that works it through pretty quickly.

[juliea]

Yeah I had the front of the car up on ramps. Can't wait to drive it again Thanks again to everyone for their help!