air filter coolant sensor? - United Bimmer Community

**buckles** · 07-25-2007, 07:07 PM

Hi

This is my first post on this BBS.

Could someone help me by advising what the sensor does which is inside the air filter box? I also think it is some type of thermostat and is part no 13541730862. It has 2 small coolant hoses going to it and can be removed with one bolt.

I managed to break mine while replacing my radiator and have joined the pipes for a temporary repair.

Thanks

Buckles

Adelaide
South Australia

**bill@bimmerclinic.com** · 07-25-2007, 07:22 PM

The part is called a Thermostat.

What is it? This thermostat controls the coolant flow to the throttle bottle to prevent the throttle body from icing over in colder climates.

If you broke yours (happens all the time, damn thermoplastics) and you joined them with union of some sort you will be totally fine. The only downfall is that your going to be constantly heating the throttle body causing higher IAT's.

drz · 07-25-2007, 10:34 PM

The sensor in the air box measures the mass air flow into the engine, which is information that the engine control unit uses to control ignition, stoichiometric mix, etc. SO its important, if that is what you want to know.

About the thermostat: it seems to me that your have broken the thermostat housing. You should replace it when you get the chance, but you should be fine with just the joined hoses temporarily.

**bill@bimmerclinic.com** · 07-26-2007, 12:12 AM

You could take that thermostat totally out of the system. I've done it to my race car and to a ton of others. The thing is the labor envolved and the mess makes it easier to just replace the thermostat and be done with it.

Believe it or not I think I have 1 or 2 sitting in the shop if you want a used one.

**buckles** · 07-26-2007, 07:32 AM

Thank you very much for the information. I will try to source a new thermostat locally, but at least I know I am not doing any real damage in the meantime.

cheers from down under