[vettegator005]

So i got the low coolant message in the morning decided i would deal with it after work. I get off work and forget i had to go to dinner. On the way to diner i get the dreaded yellow temp light followed instantly by the red temp light followed by the car shutting down. I pulled over let it cool down then got it home. Since then ive got coolant so that light is off but now the radiator fan blows full blast when i first start the car and while the fan is blowing my car runs but has no boost or power. After warming up a little the fan turns off and the car runs fine full boost full power. So ive been driving like this for a few days. Now today the same things happen but i never get boost at all, the fan came on and off but never any power or boost. The car is an 2007 335i 6mt with 56,000 miles. Is this the water pump or something more serious.

[BKV122]

It might be on the way out. When you added coolant was the expansion tank empty?

[vettegator005]

yes the expansion tank was also empty

[vettegator005]

Does that mean anything significant?

[hankcah]

Sounds like what happened with mine. Low coolant. A few months later then I noticed the fan running full blast. Later my SES light came on. Bought a diagnostic tool and mentioned the P0128 - which meant Thermostat.

Shortly after (a few weeks) I get the Overheating light and then my car stalled while attempting to pull over.

All the shops and the forum mentioned about the Thermostat and Waterpump go hand in hand. (Since they are connected to each other) they should be replaced at the same time. I paid $1100 for parts/labor at a local indie shop. I know I paid more than what I could've done it for but it's also the winter time...blah. BMW Stealership quoted me $1700 (no thanks!!)

Looking at prices on parts later I think Tischer (getbmwparts) had the cheapest pricing. Also if you look on Turner and Tischer, there's a package deal which is cheaper.

Not to scare you but also this may be helpful, since it sounds identical. I had 97k miles on my 335 though, compared to your 65k. IMO the yellow turned red coolant light was enough for me to take it to the shop.

Order your parts. And shop around the shops or plan a day of it on the weekend.

Good luck!

[LocDawgg]

Just had this problem a few weeks ago. Go to thebmwpartsstore.com they are the cheapest around. I spent about 450 in parts and 200 in labor. 650 total.

[freshnezzz]

i would just get it replaced, WILL fail eventually and leave you stranded

[BKV122]

Originally Posted by vettegator005

Does that mean anything significant?

When mine went I had same issue as you except i checked right away and had fluid all over my expansion tank so either the pump or t-stat went and overfilled the tank and all the coolant was gone. I replaced both pump and t-stat.

[Cir14]

My E90 is a non-turbo but my 0.2. I experienced a low coolant light, checked the reservoir tank and it was low. Added coolant. < 3 months later my water pump failed in rush hour traffic on a Friday afternoon. When it actually failed the yellow coolant light came on then immediately went Red less than a mile later. Luckily I was in the right lane. Best of Luck. I’ve heard estimates out of warranty of ~1K.

[BKV122]

As stated above getbmwparts.com has the package deal for both. Simple job don't need someone who specializes in bmws to replace it. It cost me about $200 labor also

[vettegator005]

Originally Posted by BKV122

As stated above getbmwparts.com has the package deal for both. Simple job don't need someone who specializes in bmws to replace it. It cost me about $200 labor also

So I checked getbmwparts.com and it comes to 585 for both the water pump and thermostat for the 335i. Is that the best deal? I think somewhere I saw a waterpump for 400 so is the thermostat really 185?

[vettegator005]

Ok so I found a water pump with aluminum screws and a thermostat from ecstuning for 486 shipped. Is this a reputable company? Is there any other parts I will need?

[BKV122]

That should be all the parts you need pump, t-stat and screws

[slow328i]

Hmm...my thermostat is "open" i guess and at bmw tbey told me i can drive on it for now as long as its noy closed its not an emergency...so should i change water pump when i change my thermostat?

[minivan]

Originally Posted by slow328i

Hmm...my thermostat is "open" i guess and at bmw tbey told me i can drive on it for now as long as its noy closed its not an emergency...so should i change water pump when i change my thermostat?

I would change it at the same time vs. having to go through the labor twice.

[phillip@bmpdesign]

Your thermostat is supposed to be open, your thermostat closes when the engine is cool to reduce the amount of time it takes your vehicle to reach normal operating temperature. If your thermostat fails, it will fail in the open position (unlike several domestic brand vehicles whose thermostat defaults to a closed and overheating state).

If your thermostat is stuck open, it will take longer for your car to reach operating temperature, but won't cause an overheat situation or a leak. The thermostat is mounted directly onto the waterpump which is why they should be replaced at the same time (you're there anyway).

To the original poster:
Your expansion tank being empty means you have a leak or an air pocket and the spray of coolant from your tank means you had an over pressure situation and is not necessarily your water pump. If your water pump was failing you would get a code (water pump speed is monitored and a speed deviation code will trip or a failure to communicate with water pump code). There are several things that could have caused this, one a leak which created an air pocket which caused temperature to rise. The second is if your fan failed then your system couldn't cool properly and an overheat situation. The third is you had an overheat situation possibly from an air pocket that has warped your head and you have a leaking head gasket which is overheating and overpressurizing your system. With a solid aluminum block, the third happens often unfortunately.

If your system overheated several components will become damaged, especially the thermostat, temp sensors, and expansion tank/cap. Your thermostat code could be an after the fact symptom and not a cause of your problem, the missing coolant is much more likely (unless you have a leak from your thermostat, but there is no code that will show that). If you need to replace your thermostat and want to do the water pump anyway, its a great time, but you need to check your cooling system for leaks to find out why you had a low coolant light in the first place.

[hjs1971]

Sorta what happened to me...on my 2008 335xi-about 7 miles into the 8 mile drive to work early Sunday (taking it nice and easy) the yellow light comes on and car goes into a minor limp mode, 20 seconds later, red light comes on and car goes to major limp mode. Leave car for 2 hours, check coolant, it's at the min level but there is still some in the tank (rules out a leak). Leave car for 2 days. Put about a cup of Prestone 50/50 in it to fill the tank and get the plunger to move, yellow light comes on 7 miles later. Stop car for 2 hrs, drive 6 miles and yellow comes on again. Whole time engine runs, radiator fan runs and wants to run when I shut the engine down until I remove the key fob. Local indie shop thinks water pump and t-stat, as do I from reading all this, however, I ONLY HAVE 35,600 MILES ON IT, WTF??? Do you think a call to BMW N.A. to ask for a little something something is out of the question, this really shouldn't happen at 35k miles. I'm sure they'll tell me to pound sand but I really think they should acknowledge my hardship with some sort of gesture. I know it's out of warranty and have to pay out of pocket but since my car is bone stock and never really driven hard, this makes me pretty mad, to say the least!

[hjs1971]

Indie shop fixed it for $1300. Said the pump itself is fine, it's the little computer inside that throws codes and of course, that can't be fixed, the whole pump needed to be replaced. Not happy about it but I got the old pump and am going to send it off to BMW and see what they say...I'll keep you posted...