[MrS3anW]

I was driving last night and my orange coolant light popped followed swiftly by the red coolant light and the car took away all power. I was able to limp it to a safe spot and when I popped the hood I heard boiling and noticed there was coolant leaking pretty bad from the bottom of my reservoir. After sitting for a while I checked the reservoir and noticed it was practically empty so I filled it back up and was able to drive 20 minutes to my house.

I scanned using Carly and I got:

002E82 - Electric coolant pump, shutdown

002E81 - Electric coolant pump, speed deviation


I would normally assume the water pump was going out but the fact my reservoir was leaking really bad and I heard bubbling from the reservoir leads me to wonder if a serious leak to the point it emptied my reservoir could be the issue.

Would the pump shutdown if it’s not being fed coolant?

[mehrlovin]

I believe it would or just burnout and fail altogether. Why did the reservoir leak?

[MrS3anW]

Originally Posted by mehrlovin

I believe it would or just burnout and fail altogether. Why did the reservoir leak?

Not exactly sure why it started leaking…it wasn’t leaking a couple weeks ago when I did my pulleys. I do know the reservoir was empty when I opened it up on the side of the road.

Would the pump shut itself off if there was no coolant in the system? I filled it last night to get home and this morning I checked and it was still full and I tried bleeding the coolant system and Didn’t have any issues. If the pump was bad wouldn’t I be able to tell when I started the bleeding process?

[Soden82]

I had the same issue in my drive home recently but I had coolant blowing out of the top of the reservoir after it boiled. Tomorrow I'm going to bleed the system twice and start the car and see if it overheats again.

I suspect your thermostat is stuck open or close. Water pump is probably fine due to the fact that it bled the system. I think that's what's going on with mine as well.

[MrS3anW]

Originally Posted by Soden82

I had the same issue in my drive home recently but I had coolant blowing out of the top of the reservoir after it boiled. Tomorrow I'm going to bleed the system twice and start the car and see if it overheats again.

I suspect your thermostat is stuck open or close. Water pump is probably fine due to the fact that it bled the system. I think that's what's going on with mine as well.

Luckily, on these cars when the thermostat goes out they stick open.

I bought a new reservoir today and I plan on installing it in the morning, hopefully that will resolve the issue. The thermostats are a pain in the ass on these cars so I am hoping to dodge that bullet.

Please keep me posted on your progress!

[mehrlovin]

The bleed process is done using the water pump so it must be working. Plus I believe you get a code from the water pump when it dies. Assuming you have no codes, then its just a leak probably.

[mehrlovin]

Check that, could be the thermostat as well. I had mine replaced with the water pump at 80k for that reason. You can certainly replace a bad thermostat by itself though.

[MrS3anW]

Originally Posted by mehrlovin

The bleed process is done using the water pump so it must be working. Plus I believe you get a code from the water pump when it dies. Assuming you have no codes, then its just a leak probably.

I did get the 2 water pump codes:

002E82 - Electric coolant pump, shutdown
002E81 - Electric coolant pump, speed deviation

My question is would I receive those codes if the reservoir was empty. When my car gave me the overheating light I pulled over and noticed I had coolant running out of the bottom of my reservoir and when I opened it I saw that the reservoir was almost completely empty.

The only reason I am confused is the fact my reservoir now has a serious leak at the exact moment my water pump started failing. What are the odds?

I would just throw a new pump and thermostat in but I am currently fighting to keep my business afloat so I am strapped for time to work on my own vehicles.

[Soden82]

Mine ended up being the water pump. I just ordered it today and had the same codes as you do.

[Efthreeoh]

OP, Your water pump is going bad. Replace it. Your car overheated, which increased the pressure in the cooling system. The reservoir cap has a vent in it that bleeds off pressure above 16 or so PSI. The coolant you saw was from the overheating condition.

You experienced the classic signs of a dying water pump and resulting overheat condition.

[E93Dude]

Though probably a fat finger incident on the keyboard, "...shit down..." in the title seems like an appropriate commentary on the E9X electric water pumps. At least they are generally consistent when the decide to shit down in terms of mileage...

[e91Owner]

You never really described if the coolant was leaking out of the cap (and running down the weep hole to the bottom of the reservoir) due to excessive pressure in the system which would indicate that the pump is going bad with those codes -or- the reservoir had a crack/leak at the bottom causing the system to cavitate which would also cause those codes. I recommend removing the reservoir entirely to inspect as it's pretty easy to do…. If you have any cracks you're going to have to replace it anyway. Refill the system/bleed and recheck for codes.

It's not a given that your pump is bad. A low fluid condition would cause the same symptoms.

[Efthreeoh]

Originally Posted by e91Owner

You never really described if the coolant was leaking out of the cap (and running down the weep hole to the bottom of the reservoir) due to excessive pressure in the system which would indicate that the pump is going bad with those codes -or- the reservoir had a crack/leak at the bottom causing the system to cavitate which would also cause those codes. I recommend removing the reservoir entirely to inspect as it's pretty easy to do…. If you have any cracks you're going to have to replace it anyway. Refill the system/bleed and recheck for codes.

It's not a given that your pump is bad. A low fluid condition would cause the same symptoms.

His pump is bad; it shut down and the engine overheated. What the OP described as happened is textbook N52 WP fail/overheat condition.

[e91Owner]

[QUOTE=Efthreeoh;28956242]

Originally Posted by e91Owner

His pump is bad; it shut down and the engine overheated. What the OP described as happened is textbook N52 WP fail/overheat condition.

Not necessarily so… coolant loss would cause the same codes. The absence of fluid at the pump inlet will cause it to overspeed and shutdown which will subsequently cause the system to overheat. If he replaced the reservoir, filled the system, bled and the codes don't reappear, it's not a bad pump. …And a cracked tank is a 5 min job to diagnose.

[Efthreeoh]

[QUOTE=e91Owner;28958493]

Originally Posted by Efthreeoh

Not necessarily soÂ… coolant loss would cause the same codes. The absence of fluid at the pump inlet will cause it to overspeed and shutdown which will subsequently cause the system to overheat. If he replaced the reservoir, filled the system, bled and the codes don't reappear, it's not a bad pump. Â…And a cracked tank is a 5 min job to diagnose.

You have the cause and effect backwards.

The OP reported the cooling system temperature warning (after the chime sounds to get the driver's attention) of first "yellow" then almost immediately "red", which is the textbook conditions that indicate an engine overheat condition (the textbook being E90 Post and the numerous overheat threads therein).


The water pump motor has a max speed. For the N52 the max speed is 250 RPM, for the turbo engines the pump speed is probably double that since the N54/N55 WP is 400 watts vs. 200 watts. The speed is controlled by the ECU dependent upon the coolant temperature and one of the four cooling system modes the engine operates under; it would spin at that max speed regardless if the cooling system was low on coolant. There is no sensor that tells the ECU there is no coolant in the system and to shut the pump off. Code 2E82 reports the WP shuts off due to elevated temperature of the motor control electronics housed in the rear of the pump housing. 2E81 reports speed deviation of the pump below the max RPM. Second, the OP did not report a low coolant condition (warning light) before the car overheated. If your theory is valid, the coolant would have leaked to a low level prior to the overheat condition and the low coolant indicator would have lit prior to the engine overheating. It would make no engineering sense for 2E81 to report an over-speed condition of the pump because it wouldn't affect cooling system performance that would endanger the engine. Besides, electric motor maximum speed is dictated by the design of the motor (i.e. windings) and what changes as the motor does work is the amperage draw.

If the coolant tank is cracked and was weakened by age, the tank would crack from the elevated cooling system pressure due to the overheating of the engine.

[blackwood]

I experience pretty much the same thing in my N55, replaced the water pump and thermostat, and now my reservoir is leaking from the cap / hoses.

[blackwood]

Replaced the reservoir and things seem back to normal.