coolant thermostat replacement with blower

Just got P0128 for the first time.  Its coolant thermostat/valve temp below control range.  I guess my thermostat is going.  Do i need to replace it right away or can i clear the code and wait for it to come back.  The car seems to be running great.
When i do replace it though, trying to figure out where to take it.  Where is the thermostat located?  Will the blower have to be removed or touched when replacing it?  Trying to decide if its safe to bring to the dealer or not.
TIA!

  It's that large plastic elbow at the front/top of the engine.  You don't need to remove the SC to change it.



Originally Posted by Solid
It's that large plastic elbow at the front/top of the engine.  You don't need to remove the SC to change it.
can you show me where?  Is it a simple DIY?

Thanks!

  I think it's right behind the fan.
so middle of the engine is where you are looking for.
But check with others.

  You'll need a torx bit set (M6 and M8).
1. Drain radiator and engine block coolant.
2. Remove air intake duct and cooling fan.
3. Disconnect electrical harness for thermostat housing.
4. Remove retaining clips and pull hoses off housing.
5. Unbolt thermostat and remove.
6. Install new one with steps in reverse.
a. Don't get oil on sealing faces.
b. Use new sealing gasket.
c. Fill coolant back up, and be sure to bleed system.
Torques:
Engine block drain plug 18 ft-lb (25 nm)
Radiator darin plug 18-27 in-lb (2-3 nm)
bmw/showparts...80amp;hg=11amp;fg=35

#4

  Thanks solid!
Just drove for 2 hours this morning and the SES light didn't come back on.  Can I wait until my SES light comes back on or should i replace the thermostat ASAP?

  There are a number of folks with thermostat/map cooling related codes. I personally have diagnosed a few. Some of whom have SES lighted and others no SES.
Like I mentioned before a SES light that extinguishes does not mean the problem has been resolved. My take is to get a GT-1 to do a complete fault code read-out and observe ECT if you can.

Originally Posted by GBX330ci
Thanks solid!
Just drove for 2 hours this morning and the SES light didn't come back on.  Can I wait until my SES light comes back on or should i replace the thermostat ASAP?



  I changed my thermo and water pump at ~65K. The only real hard part is getting the thermo out, mine was a tight fit between the engine lift point and something else, just remember I had to loosen the engine lift point to get the thermo out.



Originally Posted by Solid
You'll need a torx bit set (M6 and M8).
1. Drain radiator and engine block coolant.
2. Remove air intake duct and cooling fan.
3. Disconnect electrical harness for thermostat housing.
4. Remove retaining clips and pull hoses off housing.
5. Unbolt thermostat and remove.
6. Install new one with steps in reverse.
a. Don't get oil on sealing faces.
b. Use new sealing gasket.
c. Fill coolant back up, and be sure to bleed system.
Torques:
Engine block drain plug 18 ft-lb (25 nm)
Radiator darin plug 18-27 in-lb (2-3 nm)
bmw/showparts...80amp;hg=11amp;fg=35

#4

do i just need #4?  Do i need anything else like #5 (gasket)?

  Here it is circled it red.  Very easy DIY.  I've done this myself awhile back.


  When my thermostat was going out it was intermittent.  It would come on every other week or so.  So you should change it when you get a chance.  Be sure to keep an eye on your temperature gauge. (look for overheating or underheating)  When changing it out, you should have some coolant and distilled water on hand (to make a 50/50 mix) because you will lose quite a bit of coolant when you put off the thermostat.  Also as solid stated, BLEED THE SYSTEM!  I didn't do this and my car almost overheated!
here is a link  to a very good DIY for flushing the coolent.

Originally Posted by GBX330ci
Thanks solid!
Just drove for 2 hours this morning and the SES light didn't come back on.  Can I wait until my SES light comes back on or should i replace the thermostat ASAP?





Originally Posted by wyu
When my thermostat was going out it was intermittent.  It would come on every other week or so.  So you should change it when you get a chance.  Be sure to keep an eye on your temperature gauge. (look for overheating or underheating)  When changing it out, you should have some coolant and distilled water on hand (to make a 50/50 mix) because you will lose quite a bit of coolant when you put off the thermostat.  Also as solid stated, BLEED THE SYSTEM!  I didn't do this and my car almost overheated!
here is a link  to a very good DIY for flushing the coolent.

So i have to drain the coolant or not?  I'm confused.  Thanks!

  You can probably get away with draining very little since it's near the top.



Originally Posted by GBX330ci
So i have to drain the coolant or not?  I'm confused.  Thanks!

I don't think you NEED to but a good deal of coolant will spill out once you remove it from the engine block and the top radiator hose.
I used that opportunity to do a complete coolant flush, both radiator and engine.



Originally Posted by interalejo
I don't think you NEED to but a good deal of coolant will spill out once you remove it from the engine block and the top radiator hose.
I used that opportunity to do a complete coolant flush, both radiator and engine.

  just replaced the thermostat.  Hopefully that fixes the problem.  Thanks for everyone's help!