Over-pressurizing Cooling System. Head/Headgasket?

Originally Posted by mack89

I wish I had choice
Had to attend school daily, rental was way too expensive, no way I could had gotten 50 miles of ride back and forth til parts arrive, etc.
Circumstances weren't my friend lol. Now I'm replacing everything with OE parts. Hope it solves the problem..


By the way, does anyone know what the metal rod is? I did some googling, some say it's a heating rod as I suspected, but I need second opinion..

metal rod? IDK there are lots of metal rods on our cars. Of which dost thou speak?

It's the one located inside of thermostat housing, here's a picture of it.

guys, what about the water pump? how can you eliminate the water pump from being a possible culprit?

That stream of water inside the ET means the wp is circulating and to a lesser degree that the system is bled thoroughly.

I'm pretty confident that rod is a resistive heating element, as you suspect. You can see where the plug for the thermostat basically connects to the other end.

Could be the thermostat's temperature probe. Get a Wahler or Behr now.

Originally Posted by Cobra

guys, what about the water pump? how can you eliminate the water pump from being a possible culprit?

By replacing it along with the rest of the system.

You guys were right, at least partially.

Oreilly thermostat would not even open, even after 10 minutes of boiling water spa. Opens right up when torched. Meaning substandard defective part(SECOND DEFECTIVE PART IN A ROW!!!!). F***ing hell, what are the odds, huh? On the other hand, Behr thermostat started to open only after 15-20 seconds of insertion. I didn't even need to wait 10 minutes, that was enough confirmation.
After installing Behr thermostat, I performed bleeding procedure with enough time. Air stopped coming out of funnel and bleeding screw til warmed up. Needle was steadily staying in the middle for few minutes while RPM is at 3k. I instantly yelled 'YYYYUUUUUUUUUUSSSSSSSSS!!!!!', then went for a test drive. Engine did not even overheat after 5 minutes of pedal-to-the-metal test drive. Weird thing is, heat in the cabin wasn't strong and steady. Heats up upon acceleration, then gets weaken at idle.

HOWEVER, coolant still overflew. Once I spotted overflowing coolant, I unscrewed the bleeding screw. Before the last replacement(when oreilly T-stat and gutted thermostat were installed), quite a lot of steam came out of the bleeding screw. But this time, coolant and air were escaping through the screw at the same time. I removed the ET cap(which is new as well), started the engine, but the ET wasn't peeing stream of coolant. Almost immediately after that, coolant overflew.
I let the air out through the bleeding screw as much as I could, then went for a very short test drive. This time, heat in the cabin was hot enough at idle, but gets weaken upon acceleration. (Opposite of the last test drive.) Then I let it idle for few minutes, engine started to overheat. It was time to close the shop, so I had to park my car inside. I just drove it to inside of garage, but strangely, temperature went down as soon as I accelerated as if there was still air trapped inside.

I'm definitely missing here. So let's make a list of current condition of cooling system parts.
1) Water pump. Impeller is solid, held by shaft firmly. No bad bearing, no leaking weep hole. Stream of coolant comes out of side of ET when engine's cold, but does not when it's hot.
2) Thermostat. Behr, in great working condition.
3) Radiator. Behr, new.
4) Expansion tank. I think it's Behr, it's OE anyway. 2 months old, in perfect condition.
5) Upper & lower hoses. OE, no leak.
6) Aux fan switch, aka coolant temperature sensor. OE, new.
7) Mechanical fan & fan clutch. It's pulling air nicely.
8) Aux fan. Original, 190k miles. Working wonderfully. In fact, it's spinning too fast at idle, making too much noise.
9) Coolant inlet hose & heater return hose. Genuine, little over a year old. (Actually I haven't blown the inlet hose yet with compressed air..)

So, yeah. everything is new or less than 18 months old.
I don't think I need more replacement parts, I am definitely missing something or have not done something properly.
Such as...
1) Faulty thermostat wiring harness. I haven't checked it with circuit breaker.
2) Improperly bled heater system due to the bad water valve. Last time I removed the heater hose from the water valve, it was empty. Not even an ounce of water. Maybe I should visit BMW indy shop and have them manually open the water valve, re-do the bleeding properly.

Is there any way to manually open the water valve solenoid without INPA? #2 is my last suspect, so I don't know what else to do when it has nothing to do with this.......UUUGGGGHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!

no- you didnt bleed it enough. before i drive em- i get STRONG HOT HEAT out of the defrost vent. you still have air. jack the front of the car up as high as possible and re-bleed in the morning.



vacuuming the system down and pulling coolant in is how i do it. very quick and very efficient.

How did you bleed the system and why is coolant "overflowing" while driving?

Originally Posted by mack89

Stream of coolant comes out of side of ET when engine's cold, but does not when it's hot.

Weird. Agree you should rebleed the system (you're turning the key to POS2 with the heat on high when you do, right), but I still suspect the water valve otherwise.

Oh well, I bled the system twice while nose of car is lifted as much as possible, let the air out for 10 minutes, but no luck. Still overflows, still overheats.
I checked the water valve, it closes when power is applied. Closes and opens when I turn on/off the fan(set to 91F). Also the heater hoses were filled with coolant, so I guess I can rule out the possibilities of bad water valve and air being trapped inside of heater system.

There is a consistent symptom from beginning of this mess.
Hot upper hose, cold radiator(entire area), cold lower hose. (Sometimes lower hose would get warm, but only when it's overheated.)
I thought I was still missing something major, so I paid a visit to a reputable BMW indy shop. They also thought of two possibilities, blockage or bad/no circulation.
Luckily, they had 00 323ci at that time, engine was warmed up so I touched radiator and lower hose. They both were hot enough, unlike my car.

Well, the bleeding procedure came back negative, and still shows the same symptom.
Unlike the normal operating vehicle, radiator and lower hose is still cold even after warm up.
And the one last culprit, water pump, is not spinning freely, nor does it have broken impeller. Also the stream of coolant comes out of side of ET when cold(but not when hot).
*I'm going to replace it anyway. Having that pump makes me feel like I have a cancer, or wearing $10 walmart watch in Zegna suit.

Omg. Am I still missing something else?

Mack-

This is what an E46 therm should look like.

Where's the rest of yours?

Just curious.

Dan

He got an oe therm in how.

Mack, many here go through bleeding repeatedly, especially when opening up the system in the middle to just do something like the therm.

Have you tried the 'alternative bleeding method' I've posted about...which I learned about here? If you can't find it, I think it's in Mango's sticky somewhere.

oh **** this is easy now.


the plastic impeller is spinning when hot.

@Swordsman, picture posted above is a gutted thermostat I used for testing, new Behr one's installed right now
@Doug, DANGIT I knew I was forgetting something!!!!! I'll do that after replacing WP, thank you for reminding me!

@bigugly. WHAT?
Plastic or composite gets loosen when hot???
I guess you're saying that from experience, I will put an old one in coffee pot and see if it spins.

sounds dumb, but yea, i have seen them spin when hot. its always a good idea to replace a composite WP. i try to get the customer to buy a aftermarket pump with a metal impeller (i have a used one that is still good lol), or a stewart HP pump.

@bigugly
Well, i put the old water pump in the boiling water and tried to spin it, it didn't even move a bit. Mated part was rusted a bit, but I guess the impeller itself is good enough.

After pulling all of my hair thinking wtf is the culprit, Doug's alternative bleeding method crossed my mind. Engine was warm at that time, but I did it anyway.
Held RPM @ 4k for 30 seconds, I slowly opened the ET cap only. At first, lots of steam came out, but I kept doing it anyway. At 3rd attempt, soapy foam came out of the ET. I guess the flushing agent was still inside of the system after hard garden hose flushing. I checked the radiator, whole radiator was getting hotter than before.

Foam is still coming out of the ET. But at this point (performed Doug's method 10 times), entire radiator is hot, lower hose is hot, and upper hose was even hotter. In fact, lower hose and lower part of radiator had similar temperature according to infrared thermometer. I still need to flush the system completely, but I believe I found the culprit. 1) Thermostat 2) Damn foam created by flushing agent. Yeah, problem would have been solved if I hadn't done it.

I'll bleed several more times to flush out the foam, and do some test drive. SITREP coming up in few hours!

Originally Posted by mack89

@bigugly
Well, i put the old water pump in the boiling water and tried to spin it, it didn't even move a bit. Mated part was rusted a bit, but I guess the impeller itself is good enough.

After pulling all of my hair thinking wtf is the culprit, Doug's alternative bleeding method crossed my mind. Engine was warm at that time, but I did it anyway.
Held RPM @ 4k for 30 seconds, I slowly opened the ET cap only. At first, lots of steam came out, but I kept doing it anyway. At 3rd attempt, soapy foam came out of the ET. I guess the flushing agent was still inside of the system after hard garden hose flushing. I checked the radiator, whole radiator was getting hotter than before.

Foam is still coming out of the ET. But at this point (performed Doug's method 10 times), entire radiator is hot, lower hose is hot, and upper hose was even hotter. In fact, lower hose and lower part of radiator had similar temperature according to infrared thermometer. I still need to flush the system completely, but I believe I found the culprit. 1) Thermostat 2) Damn foam created by flushing agent. Yeah, problem would have been solved if I hadn't done it.

I'll bleed several more times to flush out the foam, and do some test drive. SITREP coming up in few hours!

Problem would have never been a problem in the first place if you would have followed my cooling thread!!!

@

I KNOW RIGHT? My belief based on percentage has totally disappointed me. Plus, my wallet was thin enough after spring semester registration

Originally Posted by mack89

@

I KNOW RIGHT? My belief based on percentage has totally disappointed me. Plus, my wallet was thin enough after spring semester registration

BTW, bleeding doesn't flush anything out. If you want to do this properly, you'll drain the block and radiator and pump a garden hose through the system until the water runs clear. Then you'll find a way to blow all the tap water out (I used a shop vac in reverse and works great with your hand cupped over the vacuum's hose so you create somewhat of a seal) then re-fill with coolant/water per my instructions.

Also replace any part that's questionable (which, really, is any part that you haven't replaced yet)

GL