[Reggwash]

2009 BMW 328i Coupe

Just replaced the radiator. Began doing the bleed procedure; filling the expansion tank, loosening the bleed screw and filling just when coolant started to come from bleed screw, heat temp set to high, blower on lowest setting, hold the brake for 10 secs. Bleed procedure started but after 12 mins it continue to do its thing. I stopped it after 20mins. I didn't want to burn the pump up or something. I could find any posts about when the bleed process continuously runs. There came a point when the pump would cycle and I'd hear gargling. Not sure what to do next. Refill and initiate the test again? After I shut things down, I check the fluid level. It had diminished but was still full. What should I try next? Thanks in advance.

[Pittz1]

I would disconnect the negative side to the battery and give it 30 seconds. Attach it back on, but put a tender on the engine terminals and try it again. If you continuously hear gurgling, try squeezing the radiator hoses for pockets of air.

This is all stuff I would try, not saying it will work. It should not run for that long. If you manage to get it to stop at 12min, run it again. That is personal preference to assure air is out.

[Efthreeoh]

Did you close the bleed screw and reservoir cap?

[Reggwash]

Yea I closed both. This was first time doing this procedure. It started off great, I guess. I could hear fluid moving, it would get quiet, then it would start doing its thing again. I set my watch, then went inside my house. Came back out approximately 15 expecting the process to be done. It was. Reason for bleeding is I just replaced the radiator.

[Pittz1]

obviously nothing leaking? coolant level is still the same?

[Reggwash]

I haven't tried your suggestion yet. This morning I checked the level. It was high. So I removed some of the fluid. And I ran it to check for leaks. Leak checked good. I'll go back out this afternoon to attempt the bleed procedure and incorporate your steps

[The Nightman]

Original water pump? It could be on its way out

[gjm120]

I assume you meant you held the gas pedal down (not brake) to start the process!?

Do you have access to INPA? If you do, start the bleed with it and it will show the 18 steps in the bleeding. Might shed some light on where the process is hanging up?

[Reggwash]

Yes. Gas pedal

[Reggwash]

You may be correct. Let's hope not. For a while I was having a P0440 code pop up intermittently. So I change the gas cap. Code still present intermittently with a check engine light every now and then. My coolant fan would come on full blast after engine was to operating temp. So I change the temp sensor next to the oil filter housing. That is didn't work. So then I change the fuel tank vent valve or purge line. Still had the P0440. I'm like no way! I go the the fuse box on the glove box. There's like 4 or 5 fuses half way in. One was the the engine coolant fan relay. Replaced the fuse and pushed them all in. My fan seems to behaving now.

[Efthreeoh]

Originally Posted by Reggwash

Yea I closed both. This was first time doing this procedure. It started off great, I guess. I could hear fluid moving, it would get quiet, then it would start doing its thing again. I set my watch, then went inside my house. Came back out approximately 15 expecting the process to be done. It was. Reason for bleeding is I just replaced the radiator.

So the bleed cycle was finished after 15 minutes? I've done the bleed procedure at least 5 times and every time it stopped at 12 minutes. The ECU controls the timing, I don't see how any outside condition of the cooling system could influence the ECU to change the timing of the procedure.

I'd be highly confident the cooling system is adequately bled once the coolant pump has run for several minutes. A traditional belt driven cooling system can trap air in the head (and over heat the cylinders) because most place the thermostat high in the cooling system and the engine has to be running to rotate the coolant pump to move the coolant through the cooling system, where air gets trapped at the t-stat until it opens.

Conversely, the N52 cooling system places the t-stat at the bottom of the cooling system and it is electrically operated (to open). The cooling circuit pushes the coolant up from the right side of the engine block (low in the block) and into the cylinder head then flows into the upper radiator hose. The upper radiator hose has a small return line that runs off the top of the upper radiator hose and under the intake snout back over to the top of the coolant reservoir. The small return line allows the trapped air to separate from the coolant (going into the top of the radiator) and return to the natural airspace in the coolant reservoir. The air separates from the coolant because the path of least resistance for the lighter (than water) air to go to the top most part of the cooling system, which is the airspace above the level of coolant in the reservoir.

[Reggwash]

It was still running. I shut it down. It ran good for several minutes. I just expected a termination of the process at 12 min.
Awesome response though. Thanks. As you explained the operation , I pictured the system in my mind. I believe there's some operator error that I need to correct. I'll get that corrected today. Everything seems to be fine. Fluid level is good, nothing odd with the pump. I know the effects is not something I'll see immediately.

I was kinda all over the place my last response. If I comprehend correctly. The N52 system is designed to eliminate air on a lower level? Me being an Avionics Technician( aircraft electronics tech.) I'm just not comfortable until I complete the test properly. I'll respond with results after I correct my error. Thanks for your response.

[Efthreeoh]

Originally Posted by Reggwash

It was still running. I shut it down. It ran good for several minutes. I just expected a termination of the process at 12 min.
Awesome response though. Thanks. As you explained the operation , I pictured the system in my mind. I believe there's some operator error that I need to correct. I'll get that corrected today. Everything seems to be fine. Fluid level is good, nothing odd with the pump. I know the effects is not something I'll see immediately.

I was kinda all over the place my last response. If I comprehend correctly. The N52 system is designed to eliminate air on a lower level? Me being an Avionics Technician( aircraft electronics tech.) I'm just not comfortable until I complete the test properly. I'll respond with results after I correct my error. Thanks for your response.

Ah, I understand your aversion now... So air in a cooling system always goes to the highest point in the system it can get to (assuming there are no blockages). So that pretty much means the cylinderhead. The design of the E9X cooling system places the top of the coolant reservoir above the cylinderhead, so the air in the system will always settle in the air gap in the reservoir. So cycling the coolant pump eventually gets air trapped in the cylinderhead to travel over to the reservoir.

[Reggwash]

So I was never able to get the bleed process to occur fully. After connecting a battery charger. Car is running great. No overheating, no leaks. BUT! Friday morning at first start the coolant Fan came on FULL BLAST. Fan restored to normal after restart. Friday evening I was driving and got a "check engine" light with no other symptoms. Using my generic code reader I got a code of P0598. Thermostat Low circuit. At this point with 187K miles I'm just going to change the Water Pump (because I couldn't get it to test fully and fan behavior) and Thermostat (because of the low circuit code). Anything else to check?

[Efthreeoh]

Originally Posted by Reggwash

So I was never able to get the bleed process to occur fully. After connecting a battery charger. Car is running great. No overheating, no leaks. BUT! Friday morning at first start the coolant Fan came on FULL BLAST. Fan restored to normal after restart. Friday evening I was driving and got a "check engine" light with no other symptoms. Using my generic code reader I got a code of P0598. Thermostat Low circuit. At this point with 187K miles I'm just going to change the Water Pump (because I couldn't get it to test fully and fan behavior) and Thermostat (because of the low circuit code). Anything else to check?

I'd say your t-stat is failing. If you can get a BMW scan tool on it, the t-stat code probably will be 2EF4, which is a bad heating element. WP codes usually are 2E81, which is slow pump speed deviation, or 2E82, where the pump will shut off. An immediate high-speed cooling fan upon start is a good indication the pump was not working.

[Reggwash]

Thanks Efthreeoh. I have the ISTA program but I'm not sure which k and Dcan connector to get.

[Efthreeoh]

Originally Posted by Reggwash

Thanks Efthreeoh. I have the ISTA program but I'm not sure which k and Dcan connector to get.

That I can't help with. I have two turn-key readers. Coding subforum is where you'll get an answer.

[Reggwash]

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