This is a quick DIY about how to replace the thermostat in your R32.
It seems that a lot of them are getting stuck and are causing a MIL at this time of the year, particularly as the cars are turning 5 years old. In my case, it generated DTC 18613 P2181. Make sure your cooling fans are operating properly before proceeding, as it will save you time.
Removing the entire [plastic] thermostat assembly from the side of the head is the easiest way to do this, and is the recommended method in the Bentley service manual. There are helpful diagrams in the manual, but i cannot post them because they are copywrited. I would advise you to review them prior to this project just because it helps.
- hose clip pliers, unless you want to use a more difficult method like vise-grips, etc.
- 5mm hex bit
- ratchet for the above
- 6" extension for the above
- T-20 torx bit / wrench to remove plastic plenum(s) under engine (bellypan)
- normal assortment of screwdrivers
- nitrile gloves and a small piece of plastic sheeting, 2 mil thick is ok
- thermostat: 022 121 113
- gasket ring for the above: N 901 368 02
- gasket between t-stat assembly and head: 021 121 119 A
- G12 coolant and distilled water to mix 50/50 or so and refill the system
Other parts upon your choice:
- coolant distribution (crack) pipe O-ring: N 101 392 01
- new green-top coolant temp sensor: 059 919 501 A
- O-ring or 'seal' for the above: N 903 168 02
- retaining clip for CTS above: 032 121 142
- the 3 metal clamps for the coolant hoses on the thermostat assembly:
N 909 265 01
N 906 871 01
N 906 872 01
To replace the entire plastic coolant flange on the side of engine if it is suspect or warped:
top part that bolts to head: 022 121 117 C
bottom part under the thermostat: 022 121 121 E
DON'T OVERTIGHTEN ANYTHING PLASTIC, IT WILL BREAK !!
I could not fit a torque wrench in the area needed.
Ok, here we go, basic prep:
Use the torx T-20 bit to remove the center and left side belly pan (plastic plenums) under the car. I chose to drain all of the coolant out prior to this job because i did not want excess to spill onto my shifter assembly, the grounding point that is near it, the SAI pump, starter, and the associated electrical connectors. It is manageable if you use some old towels to clean up what leaks out. I am not proud; i drained the coolant into a [new] cat litter pan.
Wear eye and hand protection; try not to take a bath in G12; it is toxic. Please make sure to dispose of or recycle it properly in compliance w. your local laws. It cannot be dumped outside or flushed down a sewer.
Time to start, cooling things off w. fans.
Remove the engine and battery box cover:
Remove the center and left side plastic undertrays (bellypans, whatever..) so you can drain the coolant. When you have the plastic shields off, get under the car and look up towards the left side of the radiator and observe the connecting hose and how to remove it. It is held in place by a metal clip over the plastic 'quick' connector. Pry the bottom prongs loose w. a screwdriver, then pop the whole clip up and off where the green arrow is pointing:
I threw this together quickly, so my arrows, circles, pics, and whatever are not very good.
This what the lost coolant looked like when completely finished; the black debris is dirt that was washed from the engine bay on its way down to the kitty pan:
Remove the battery and battery tray:
This is what we are going to remove:
Put in some plastic to protects the vitals:
Take the biggest hose off first, note the hose-clamp pliers:
All 3 hoses removed:
Remove these bolts w. the 5mm. hex bit:
Use the 6" ratchet extension to get the smallest one last (to the left you can see where the 2 longer bolts have been removed):
Here are the bolts on the garage floor. Not sure why i took this pic:
Pull the t-stat assembly away from the head. Pull it back straight and smoothly off of the 'crackpipe'. We don't want to dislodge the other end which is on the other side of the head at the water pump.
Remove CTS and its retaining clip:
Remember to replace the O-ring.
Up and out !
Now there is easy access to the thermostat:
I cleaned up the flange on the head w. only a paper towel:
Here is the infamous crack pipe O-ring. Lube a new one w. coolant and replace.
NOTE: NEVER twist an O-ring. Just apply firm pressure and push straightly. It won't hop over the lip on the flange, don't worry-- but if you twist it will tear and be ruined !
All cleaned up and on the operating table:
I took this shot for ian (Daemon42). In an old thread he talked about etching in points of grip on the small hex bolts w. a Dremel. Mine seemed to have them from the factory, dunno:
Take out the 3 5mm alllen bolts:
Carefully pry out the old thermostat w. a flat blade screw driver. Put the new one in after lubing the new gasket w. coolant:
Replace this important gasket. Pry the old one out very carefully w. a small flatblade screwdriver, then lube the new one w. coolant before working it back into the channel in the plastic housing:
Gaskets and O-rings:
Hose clamps and clamp pliers:
Correction to pic above: the smallest clamp, the rightmost one, is p/n N 906 871 01
credits to the Above-and-Beyond crowd:
BLU R32 (Joe)
all the rest of 'ya
edited to correct a part #.
Modified by VeeRsixx at 6:51 PM 10-20-2009