[RobertoTaylor]

Okay guys, I have a 2007 e90 BMW 335i. About a month ago, my car overheated due to a water pump failure. My brothers shop replaced both the thermostat and water pump with OEM parts and everything was fine.

3 weeks later, I started having issues with the alternator which stopped working. Replaced that with an aftermarket Bosch alternator, and was running into some weird issues where it wasn't charging all the time. The only way I could "force" it to start charging, was by revving my engine past 5K RPM (weird, I know).

After a lot of research, it was determined the alternator was bad which apparently is not uncommon. Took the car to the shop, replaced the alternator with a new one, but now they ran into a new problem. Once they connected the battery, the water pump turned on (car was off), and it will just continue to run without stopping. It will basically keep running until it drains the battery completely.

My brothers shop does not specialize in BMW's, but they've checked everything possible. All connections are good, but we just can't figure out what the problem is.

Does anyone have any ideas as to what could be causing this before I decide to send it to the dealer and get my head ripped off? Any help will be greatly appreciated.

Thanks!

Uploaded an audio clip to YouTube so you can hear what the pump does when the battery is connected. Listen until the end when it goes and stays at full speed!

UPDATE:

After some additional testing, we determined it was the pump that was bad. Called the dealer since it was only a month old, and they had me bring the car in with the pump installed. They diagnosed it and confirmed it was the pump. They took care of replacing it all under warranty (thought that was pretty cool), and everything seems to be back to normal now. We even swapped the alternator back for the OEM one, and it has had no problems.

[dtla1]

Originally Posted by RobertoTaylor

Okay guys, I have a 2007 e90 BMW 335i. About a month ago, my car overheated due to a water pump failure. My brothers shop replaced both the thermostat and water pump with OEM parts and everything was fine.

3 weeks later, I started having issues with the alternator which stopped working. Replaced that with an aftermarket Bosch alternator, and was running into some weird issues where it wasn't charging all the time. The only way I could "force" it to start charging, was by revving my engine past 5K RPM (weird, I know).

After a lot of research, it was determined the alternator was bad which apparently is not uncommon. Took the car to the shop, replaced the alternator with a new one, but now they ran into a new problem. Once they connected the battery, the water pump turned on (car was off), and it will just continue to run without stopping. It will basically keep running until it drains the battery completely.

My brothers shop does not specialize in BMW's, but they've checked everything possible. There are no codes in the system, all connections are good, but we just can't figure out what the problem is.

Does anyone have any ideas as to what could be causing this before I decide to send it to the dealer and get my head ripped off? Any help will be greatly appreciated.

Thanks!

JB4? There was an issue with the water pump running continuously with JB4 installed, but I seem to recall that was N55 only?

[RobertoTaylor]

Originally Posted by dtla1

JB4? There was an issue with the water pump running continuously with JB4 installed, but I seem to recall that was N55 only?

No JB4 or other mods done to the car right now.

[fazman]

Originally Posted by RobertoTaylor

Okay guys, I have a 2007 e90 BMW 335i. About a month ago, my car overheated due to a water pump failure. My brothers shop replaced both the thermostat and water pump with OEM parts and everything was fine.

3 weeks later, I started having issues with the alternator which stopped working. Replaced that with an aftermarket Bosch alternator, and was running into some weird issues where it wasn't charging all the time. The only way I could "force" it to start charging, was by revving my engine past 5K RPM (weird, I know).

After a lot of research, it was determined the alternator was bad which apparently is not uncommon. Took the car to the shop, replaced the alternator with a new one, but now they ran into a new problem. Once they connected the battery, the water pump turned on (car was off), and it will just continue to run without stopping. It will basically keep running until it drains the battery completely.

My brothers shop does not specialize in BMW's, but they've checked everything possible. There are no codes in the system, all connections are good, but we just can't figure out what the problem is.

Does anyone have any ideas as to what could be causing this before I decide to send it to the dealer and get my head ripped off? Any help will be greatly appreciated.

Thanks!

Are you getting any codes? When you say running continuously... do you mean from an overnight dead cold start you hear the water pump flowing at first crank of the motor in the morning???

OR

Do you mean it runs greater than 13+ minutes after vehicle is shut down after a nice drive?


I would assume you would have a code and possibly clearing all codes/history of codes might help you get to the bottom of this. In INPA there are three places to see codes for the engine. When I want a clean slate to check for issues I clear all three of them (including the read history).

The only thing I can guess at... if the thermostat thinks it needs to be open so the WP can flow the coolant, that would make sense and means your t-stat might be failed/failing??? (I'm guessing here)

[RobertoTaylor]

Originally Posted by fazman

Are you getting any codes? When you say running continuously... do you mean from an overnight dead cold start you hear the water pump flowing at first crank of the motor in the morning???

OR

Do you mean it runs greater than 13+ minutes after vehicle is shut down after a nice drive?


I would assume you would have a code and possibly clearing all codes/history of codes might help you get to the bottom of this. In INPA there are three places to see codes for the engine. When I want a clean slate to check for issues I clear all three of them (including the read history).

The only thing I can guess at... if the thermostat thinks it needs to be open so the WP can flow the coolant, that would make sense and means your t-stat might be failed/failing??? (I'm guessing here)

Yes, there are some codes. I'll have to text the shop and find out the codes that are popping up.

The water pump will run continuously doing a strange type of cycle as soon as you connect the battery without even starting the car, even if the car is completely dead. It will continue to run in the same manner until the battery dies.'

I took an audio clip and uploaded to YouTube so you can hear what I'm dealing with. Listen until the end so you can hear when it goes into high mode and stays there.

[Nitrousbird]

The water pump running full blast non stop was what happened to mine when it died.

[fazman]

Originally Posted by RobertoTaylor

Yes, there are some codes. I'll have to text the shop and find out the codes that are popping up.

The water pump will run continuously doing a strange type of cycle as soon as you connect the battery without even starting the car, even if the car is completely dead. It will continue to run in the same manner until the battery dies.'

I took an audio clip and uploaded to YouTube so you can hear what I'm dealing with. Listen until the end so you can hear when it goes into high mode and stays there.

It sounds like that pump is failing OR a weak battery is causing the Waterpump to act strange. (Weak batteries can cause all sorts of problems). If your existing battery is old, I would strongly suggest you replace the car battery first then dig more into the waterpump.

[RobertoTaylor]

Battery is brand new, and the water pump is just a month old.

[PichaDis11]

Were the codes cleared or are they still stored?

[RobertoTaylor]

Originally Posted by PichaDis11

Were the codes cleared or are they still stored?

Cleared, but they came right back. Going to have to wait until tomorrow to get the codes that are popping up.

[Nitrousbird]

I bet the pump is shot. As I said above that is what happened to mine.

[fazman]

Originally Posted by RobertoTaylor

Battery is brand new, and the water pump is just a month old.

Here is a fun fact, I recently had my waterpump, Tstat, and reservoir changed out (old one didn't fail yet... but the subframe was out so Indy did it since it's about 105k miles on the original pump anyways)... after 200 miles my brand new waterpump permanently failed 4 days later. had to tow it back 105 miles to my Indy for another new one

[fazman]

Originally Posted by Nitrousbird

The water pump running full blast non stop was what happened to mine when it died.

+1 I started mine up in the morning after sitting over night on a cold night. Motor cranked up, a couple seconds later my radiator fan was on full blast, i was thinking... hummm thats strange, drove a couple blocks and said... let me check for codes with the JB4... sure enough a code so I drove it back home and parked it (Took my dependable pickup truck to work instead).

[kkasson]

It doesn't sound like the pump to me since it's turning on immediately when the battery is connected, even before the car is started. If the pump is dying then the car will turn the fan on high to prevent the car from overheating...but I don't think the pump would be running if the car hasn't even been turned on yet.

But the pump can continue to run after the car has been turned off if it thinks it needs extra cooling, or when the residual heat function is on, etc.

It could be the pump, but I think it could also be a bad temperature sensor or some other electrical issue that's making the ECU think the pump should be running?

[RobertoTaylor]

Originally Posted by kkasson

It doesn't sound like the pump to me since it's turning on immediately when the battery is connected, even before the car is started. If the pump is dying then the car will turn the fan on high to prevent the car from overheating...but I don't think the pump would be running if the car hasn't even been turned on yet.

But the pump can continue to run after the car has been turned off if it thinks it needs extra cooling, or when the residual heat function is on, etc.

It could be the pump, but I think it could also be a bad temperature sensor or some other electrical issue that's making the ECU think the pump should be running?

That's what I'm thinking too. Pump is OEM and only a month old. This started after the alternator was swapped out a second time.

[Nitrousbird]

Originally Posted by kkasson

It doesn't sound like the pump to me since it's turning on immediately when the battery is connected, even before the car is started. If the pump is dying then the car will turn the fan on high to prevent the car from overheating...but I don't think the pump would be running if the car hasn't even been turned on yet.

A pump dying doesn't mean the pump itself stops working. It can be the controller in the pump dying as well. Mine did EXACTLY as you are describing - it ran full blast any time the battery was connected. Swapped it out and have never had a problem since.

[PichaDis11]

Any updates to the codes as yet OP?

[kiel_dafo_kenyg_as]

Dude, you're complaining about a steady running water pump. Others complain about pumps going bad every now and then. Considering the average time of successful pumping BMW must think they're on the right way, LOL!
SCNR!

[RobertoTaylor]

Long story short, it was the pump that was bad. Took it to the dealer, they diagnosed it, replaced the pump with a new one, and everything is back to normal. So happy to have her back!

[Nitrousbird]

Originally Posted by RobertoTaylor

Long story short, it was the pump that was bad. Took it to the dealer, they diagnosed it, replaced the pump with a new one, and everything is back to normal. So happy to have her back!

I called that one.

[SpeedKingZR1]

One thing I see that is often overlooked after performing repairs to the cooling system is people forgetting to plug the electric fan back in. Unplugging the fan will deafult the coolant pump to run at full speed to prevent overheating. Just FYI.

[thomas88162]

Originally Posted by Nitrousbird

A pump dying doesn't mean the pump itself stops working. It can be the controller in the pump dying as well. Mine did EXACTLY as you are describing - it ran full blast any time the battery was connected. Swapped it out and have never had a problem since.

I have to agree here. One issue with these waterpumps is that the control module gets flooded out with coolant. Obviously with water in the mixture, it could be completing a circuit..