2011 328i 57k miles Water Pump failure or fan failure?

BimmerNugget · 06-20-2017, 02:06 AM

Hey guys,

So I'm sort of in a weird situation, long story short, I'm not sure if my water pump/thermostat is busted or my radiator fan. I was driving home from Sears, when the first issue started in the parking lot. I turned on the A/C and it does not blow cold, just regular warm air. Normally my A/C blows a nice frigid air within 10 seconds of turning it on. I waited about 4-5 minutes and still nothing, so I pulled out of the Sears parking lot getting ready to head home. As soon as i start moving about 30mph+, my A/C was magically cold again. When I stopped at traffic lights, the A/C would not blow cold.

I got on the parkway doing 50mph and everything was great for about 2 miles until I hit traffic. Of course when I hit traffic, the A/C began to blow warm air again since we weren't moving. However, within 10 seconds of being in traffic the engine overheating light came on (the thermostat symbol). First it was yellow, then it turned red. I immediately pulled over and shut the car off. Luckily I had a AAA subscription, got a 9 mile tow to my house for $33.

As soon as the yellow/red thermostat light came on, I thought the water pump was the culprit as this is a fairly common issue on E90s. However upon some more analyzing, I think it might have been the radiator fan since there was no cold A/C.

Can anyone help chime in here? Anyone experience loss of A/C followed by overheating?

JuniorB · 06-20-2017, 01:05 PM

Loss of ac,look into the diverter valve,or the HVAC door isn't closing for cold air, make sure there isn't anything obstructing air flow thru the radiator, and make sure your fan is kicking on when the ac is. If your overheating at idle, your not pulling enough air, or coolant flow.

Joebie · 06-20-2017, 01:14 PM

I'm fairly confident, but not 100% sure, that if your A/C is on, the radiator fan should always be on too. That's a quick check to see if the fan's working.

Can anyone else confirm this to be true?

Let the car cool, then start it, turn it to max A/C, and look at the radiator fan. Then turn car off. Car will only have the be started for all of 10 seconds and should be fine even if the water pump is the problem, assuming you let it cool off first.

N52UNED · 06-20-2017, 11:57 PM

Quote:

Originally Posted by Joester

I'm fairly confident, but not 100% sure, that if your A/C is on, the radiator fan should always be on too. That's a quick check to see if the fan's working.

Can anyone else confirm this to be true?

Let the car cool, then start it, turn it to max A/C, and look at the radiator fan. Then turn car off. Car will only have the be started for all of 10 seconds and should be fine even if the water pump is the problem, assuming you let it cool off first.

Sounds about right. Doesn't take but a minute until I hear my fan start up when the AC is on at idle (I don't believe BMW's have 2 smaller fans like Audi ... just haven't bothered to look well enough)

A non-working radiator fan will make the engine temp go up fast.

OP ... Did you smell the sickly-sweet smell of radiator fluid? Not sure about BMW's but every water pump I've had start to go, I've smelled radiator fluid. The only time I hadn't .... the pump went the moment I turned off the car ... then there was no doubt it went.

BimmerNugget · 06-21-2017, 12:54 AM

Joester N52UNED

The coolant is 100%, no coolant leak at all.

I started the car again today, turned A/C on and took a look under the hood while A/C running. Confirmed that the front radiator fan does not spin.

I also disconnected the fan from car and connected it to a 12v battery, with jumper cables and alligator clips, fan still does not spin.

So it's confirmed that this radiator fan is the defective and not the water pump? What do you guys think?

I might just replace the fan and see if that solves the overheating issue and A/C problem.

JuniorB · 06-21-2017, 05:31 AM

Yes, there is only one fan in front, usually the temp sensor will trigger the fan relay, do you have access to a temp gauge? There should be a simple two wire plug to the fan, if it doesn't work with direct power, it's either stuck or failed. Make sure your getting power there first,unplug the fan and check k for power, it should be present with the car running hot,being unplugged will allow the relay to reset but still be able to send power.

rjahl · 06-21-2017, 07:35 AM

If you are going to work on your own car, Invest in a good Dcan cable and pick up a copy of BMW tools. Using INPA you can check the fan, water pump and thermostat with your laptop. Less than $50.00 and you can have dealer level diagnostics.

Anyways, Old school method to test the water pump. Turn on the heater, if you get hot air with a warmed up engine, you know the water pump is pumping some water. You still won't know what's happening to the fan or thermostat.

Joebie · 06-21-2017, 08:19 AM

If the fan doesn't work with direct 12V applied, start by replacing or repairing the fan.

Then see if there is still a problem.

hassmaschine · 06-21-2017, 06:10 PM

If the waterpump isn't working you'd get the yellow and red overheat warning lights within about 15 minutes of normal driving. It's probably the fan.

BimmerNugget · 06-21-2017, 09:14 PM

Thank you all for the replies. Just ordered a new radiator cooling fan. Should get here in 4-5 days.

From this DIY guide, it doesn't look like the fan is too difficult to replace. Just need T20 torx and T25 torx. Maybe a 1.5 hour job tops.

http://www.pelicanparts.com/BMW/tech..._Replacing.htm

I will report back in about a week after I get the new fan installed.

06-20-2017, 02:06 AM	#1
BimmerNugget Crazy Frog 560 Rep 1,215 Posts Drives: L.L.Bean Bootmobile Join Date: Jun 2017 Location: 560 State Street iTrader: (0)	2011 328i 57k miles Water Pump failure or fan failure? Hey guys, So I'm sort of in a weird situation, long story short, I'm not sure if my water pump/thermostat is busted or my radiator fan. I was driving home from Sears, when the first issue started in the parking lot. I turned on the A/C and it does not blow cold, just regular warm air. Normally my A/C blows a nice frigid air within 10 seconds of turning it on. I waited about 4-5 minutes and still nothing, so I pulled out of the Sears parking lot getting ready to head home. As soon as i start moving about 30mph+, my A/C was magically cold again. When I stopped at traffic lights, the A/C would not blow cold. I got on the parkway doing 50mph and everything was great for about 2 miles until I hit traffic. Of course when I hit traffic, the A/C began to blow warm air again since we weren't moving. However, within 10 seconds of being in traffic the engine overheating light came on (the thermostat symbol). First it was yellow, then it turned red. I immediately pulled over and shut the car off. Luckily I had a AAA subscription, got a 9 mile tow to my house for $33. As soon as the yellow/red thermostat light came on, I thought the water pump was the culprit as this is a fairly common issue on E90s. However upon some more analyzing, I think it might have been the radiator fan since there was no cold A/C. Can anyone help chime in here? Anyone experience loss of A/C followed by overheating?
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06-20-2017, 01:05 PM	#2
JuniorB Major 186 Rep 1,017 Posts Drives: 07 e60 525 N54 Join Date: Mar 2016 Location: Rhode Island iTrader: (0)	Loss of ac,look into the diverter valve,or the HVAC door isn't closing for cold air, make sure there isn't anything obstructing air flow thru the radiator, and make sure your fan is kicking on when the ac is. If your overheating at idle, your not pulling enough air, or coolant flow.
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06-20-2017, 01:14 PM	#3
Joebie Grandmaster 928 Rep 890 Posts Drives: 2018 ///M2 6MT Join Date: Dec 2014 Location: St. Louis iTrader: (0)	I'm fairly confident, but not 100% sure, that if your A/C is on, the radiator fan should always be on too. That's a quick check to see if the fan's working. Can anyone else confirm this to be true? Let the car cool, then start it, turn it to max A/C, and look at the radiator fan. Then turn car off. Car will only have the be started for all of 10 seconds and should be fine even if the water pump is the problem, assuming you let it cool off first. __________________ Daily - 2018 Alpinweiß ///M2 6MT Exec Rain/Snow/Winter - 2011 328i 6MT Sedan - Black on Black, Sport Package Sold, But Not Forgotten - 2009 135i 6MT - Black on Black, M-sport, JB4
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06-21-2017, 12:54 AM	#5
BimmerNugget Crazy Frog 560 Rep 1,215 Posts Drives: L.L.Bean Bootmobile Join Date: Jun 2017 Location: 560 State Street iTrader: (0)	Joester N52UNED The coolant is 100%, no coolant leak at all. I started the car again today, turned A/C on and took a look under the hood while A/C running. Confirmed that the front radiator fan does not spin. I also disconnected the fan from car and connected it to a 12v battery, with jumper cables and alligator clips, fan still does not spin. So it's confirmed that this radiator fan is the defective and not the water pump? What do you guys think? I might just replace the fan and see if that solves the overheating issue and A/C problem.
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06-21-2017, 05:31 AM	#6
JuniorB Major 186 Rep 1,017 Posts Drives: 07 e60 525 N54 Join Date: Mar 2016 Location: Rhode Island iTrader: (0)	Yes, there is only one fan in front, usually the temp sensor will trigger the fan relay, do you have access to a temp gauge? There should be a simple two wire plug to the fan, if it doesn't work with direct power, it's either stuck or failed. Make sure your getting power there first,unplug the fan and check k for power, it should be present with the car running hot,being unplugged will allow the relay to reset but still be able to send power.
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06-21-2017, 07:35 AM	#7
rjahl Colonel 1002 Rep 2,287 Posts Drives: Z4 35is Join Date: Jun 2011 Location: Tampa iTrader: (0) Garage List 2012 Z4 35is [0.00]	If you are going to work on your own car, Invest in a good Dcan cable and pick up a copy of BMW tools. Using INPA you can check the fan, water pump and thermostat with your laptop. Less than $50.00 and you can have dealer level diagnostics. Anyways, Old school method to test the water pump. Turn on the heater, if you get hot air with a warmed up engine, you know the water pump is pumping some water. You still won't know what's happening to the fan or thermostat.
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06-21-2017, 08:19 AM	#8
Joebie Grandmaster 928 Rep 890 Posts Drives: 2018 ///M2 6MT Join Date: Dec 2014 Location: St. Louis iTrader: (0)	If the fan doesn't work with direct 12V applied, start by replacing or repairing the fan. Then see if there is still a problem. __________________ Daily - 2018 Alpinweiß ///M2 6MT Exec Rain/Snow/Winter - 2011 328i 6MT Sedan - Black on Black, Sport Package Sold, But Not Forgotten - 2009 135i 6MT - Black on Black, M-sport, JB4
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06-21-2017, 06:10 PM	#9
hassmaschine Major General 3987 Rep 7,212 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	If the waterpump isn't working you'd get the yellow and red overheat warning lights within about 15 minutes of normal driving. It's probably the fan.
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06-21-2017, 09:14 PM	#10
BimmerNugget Crazy Frog 560 Rep 1,215 Posts Drives: L.L.Bean Bootmobile Join Date: Jun 2017 Location: 560 State Street iTrader: (0)	Thank you all for the replies. Just ordered a new radiator cooling fan. Should get here in 4-5 days. From this DIY guide, it doesn't look like the fan is too difficult to replace. Just need T20 torx and T25 torx. Maybe a 1.5 hour job tops. http://www.pelicanparts.com/BMW/tech..._Replacing.htm I will report back in about a week after I get the new fan installed.
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