[Nitrousbird]

Getting the thermostat code and the car is intermittently running 5-10 degrees too cool. Must be a German car thing - my wife's thermostat in her Audi went out way sooner than expected as well.

Regardless, I'd rather not blow $480 to fix an $80 problem. Of course I have no idea when (or if) the water pump has been replaced previously.

The laziness in me says do it all at once, so I don't have to dig in there again. The cheap ass in me says "why blow $400 to replace a perfectly good pump?"

Any thoughts?

[LaserPower]

Well why don't you fire up the pump and find out? Start the pump without starting the engine. The pump should not make any noise other than from circulating the water.

[fravel]

Granted, I'm driving an N52, but... my car presented with the same symptoms and I didn't change my waterpump. Car threw code for thermostat, so I started monitoring coolant temp via hidden menu and noted that it was taking longer to get up to temperature and then settling at a lower average temperature when cruising.

I replaced thermostat, flushed with new coolant mixture then ran the bleeding process. I've put about 4,000 miles on it since then and so far so good.

[Nitrousbird]

Never tried just running the water pump on its own. Should I do it just using the Rest feature or can I activate it using INAP?

[fravel]

I would just do the coolant bleed procedure if you want to verify waterpump function. Key in ignition, car on but engine not started - turn heat to max then hold down accelerator for ~30 sec. You'll hear the water pump kick on and coolant start cycling. Kinda sounds like a dishwasher, runs for 12 mins.

[Fundguy1]

Probably but while your there why not do it as preventative maintenance. these pumps typically go after 75,000 miles. mine was a hero with 200,000 when it blew. part is $390 @ getbmwparts. Saves you the cost of the tow and gives you peace of mind.

[ucdbiendog]

Originally Posted by Fundguy1

Probably but while your there why not do it as preventative maintenance. these pumps typically go after 75,000 miles. mine was a hero with 200,000 when it blew. part is $390 @ getbmwparts. Saves you the cost of the tow and gives you peace of mind.

this. mine went at 108 and i knew i was on borrowed time. kept putting off the water pump, despite what i read on here about these things failing at 75k. long story short, car stranded me, so i got to pay a tow bill plus the replacement parts. yay.

[Wilt]

Lots of water pumps fail in the 50K-70K interval; some fail sooner, some go 120K, and you real one lucky soul's 200K!

So depending upon your car's mileage, you are placing a statistical bet.
Ask yourself, "How much extra money do I have to 're-spend' on labor by putting off the water pump and not doing it at the same time as the thermostat replacement?"

[Fundguy1]

labor and tow too not to mention the inconvenience of being stranded. I got stuck on the Florida turnpike for 2 hours.

[lightspeedbriefs]

Originally Posted by Wilt

Lots of water pumps fail in the 50K-70K interval; some fail sooner, some go 120K, and you real one lucky soul's 200K!

So depending upon your car's mileage, you are placing a statistical bet.
Ask yourself, "How much extra money do I have to 're-spend' on labor by putting off the water pump and not doing it at the same time as the thermostat replacement?"

This

[kiel_dafo_kenyg_as]

Would changing the water pump and keeping the old pump as a spare make sense?
Whith the pump out and no hurry maybe you can overhaul it if something is out of spec? There should be nothing special inside

[Underground6t9]

No the reason why pumps fail is because the seal breaks leaking water into the circuit. Replace pump now and not worry about it for another 80k

[LaserPower]

Originally Posted by Nitrousbird

Never tried just running the water pump on its own. Should I do it just using the Rest feature or can I activate it using INAP?

Neither. Water pump can be run with key in acc mode and push on the gas pedal for about 20 seconds. This will put the pump in coolant recirculation mode, and is intended to cycle coolant after coolant replacement to get the air out of the system without running the engine so the coolant will not get too hot in the process. Beauty of an electric pump.

[roadkillrob]

I would do them both, if it is an 07 with original pump it is a ticking time bomb and you are doing all the labor once you have the thermostat out, the pump is easy, if your paying someone, you will pay labor twice if you wait. Only way to tell is get the part number off the pump and see if it is one of the original problem part numbers or the new updated pump that has not been change since about 2012.

[hassmaschine]

Originally Posted by Underground6t9

No the reason why pumps fail is because the seal breaks leaking water into the circuit. Replace pump now and not worry about it for another 80k

no that is not why they fail. I opened mine as have others - bone dry inside. Something inside the circuit was made cheaply and it just burns out. as far as I could tell, the inside of the pump was immaculate.

[mweisdorfer]

It depends on how many miles you have on the car? If you are between 75,000 and 110,000 miles then you should replace both the thermostat and the water pump. Probably 1% of all e90 BMW's will make past 110k with the original water pump. If some some assurances on making the next water pump last a little longer, run AMSOIL coolant and cut it with 50% distilled water and then add 8 ounces of AMSOIL coolant booster to each gallon of your mixture of distilled water and AMSOIL coolant.

Make sure you do a complete flush of the old fluid before adding you new coolant. You can use distilled water; some add a detergent. Prestone makes one.

You can make the DIY easier if you take out the fan and inner cooler. That will give you more room to work with. There is a great DIY on the Bav Auto site.

[Grip Grip]

I guess it's time to start ordering parts. My thermostat is dead and at 110k miles I believe I'm on the stock pump.

[hassmaschine]

I must have a unicorn - 110k and going strong. I changed the error codes for the pump to trigger a CEL, i want to know if they will give me any advanced warning of pump failure.

Even my wife' s car, which was not well maintained, lasted to 90k.

[Douche]

Originally Posted by hassmaschine

I must have a unicorn - 110k and going strong. I changed the error codes for the pump to trigger a CEL, i want to know if they will give me any advanced warning of pump failure.

Even my wife' s car, which was not well maintained, lasted to 90k.

What year? I guess it fails with time (hours engine run).

Mine is a 2007 and it was replaced with 50k miles last year (so 50k / 7 years). It has 64 miles today.

[hassmaschine]

Both are 2006, i think mine is 5/2005 and hers is 7/2005.

[TheMidnightNarwhal]

Originally Posted by hassmaschine

I must have a unicorn - 110k and going strong. I changed the error codes for the pump to trigger a CEL, i want to know if they will give me any advanced warning of pump failure.

Even my wife' s car, which was not well maintained, lasted to 90k.

How the hell did you do that? Is it just a simple coding option or something more in depth? To make shadow codes pop as a CEL?

Yeah I know old thread but I know you're still active so I wanted to ask haha.

[hassmaschine]

It's not coding. I modified the flash tune. Maybe you could do it with a custom MHD file, but you'd have to know how to edit the binary to turn *on* the CEL.