Aftermarket/Larger Radiator - How do you deal with EAC Sensor (Prem-Air Sensor)?

[Bullitt]

Originally Posted by ugabuga

The radiator has a big sensor built into the front of it. If you didn't see it you don't have one.

ugabuga, is your transmission auto or a 6MT?

[ayao]

Originally Posted by Ginger_Extract

Guessing the sensor may be for specific models only. My 6MT US-spec 135i didn't have anything like that.

Test results/write-up on the CSF Racing Radiator that I use:
http://oppositelock.kinja.com/my-tho...ato-1745809742

Great review. My 1M has never limped (knock on wood) but the oil temp needle has kissed ~275F in 105+ ambient a few times. Strongly considering the CSF radiator. Any thoughts about effectiveness of uprated intercooler?

[Gangplank]

So I'm wondering if the sensor is using an electrical current. If so then all that's needed is to measure the current w: it on the stock radiator vs off it. Then just jumper it with a resistor to feed back the same current. It will resister as if the old radiator is a-ok.

[bNks334]

I've been looking into radiator upgrades or retrofitting the 135i oil cooler for my 128i, and I noticed that the sensor seems to be specific to n51 engine varients. I think the sensor is for the special coating the n51 radiators get...

[houtan]

Has anyone contacted csf regarding the missing sensor?

[Gangplank]

I think it's only on the n51 models no??

[houtan]

Could be. I know the 135 auto/DCT and 1m have the transmission heat exchanger, but not sure if they have the same sensor on the radiator.

[bNks334]

I should've been more clear. The sensor is definetly for the prem air coating the n51 varient radiator gets. I wouldn't expect to find any aftermarket radiators with the coating or the sensor... does a check engine light even come on if you unplug it?

The sensor is part of the efficiency/emissions changes to the n51. It has nothing to do with the heat exchanger on the autos.

Seems like money is better spent on upgrading/retrofitting the oil cooler in the passenger wheel well. That in turn will help keep coolant temps a couple degrees cooler. All my observations and research shows that oil temps cause limp mode before coolant temps do. My auto 128i n51 saw temps of 127c oil (car pulls power at 132c) and 96c coolant (car pulls power at 117c) on the street. On track in 90f weather I saw coolant temps as high as 110c and oil as high as 140c!!!

Even crazier is that "dsc excessive brake temperatures" put me into limp mode each session before oil and coolant ever did...

[houtan]

Cool. Thanks for the additional information.

[bNks334]

"N51 engines use a manganese oxide coated radiator that works to reduce ambient air ozone. This radiator uses an EAC (Environmental Air Catalyst) sensor to check that the special coated radiator if fitted to the car.

NOTE-
The EAC sensor is hard wired to the radiator so that it cannot be disconnected. In the event of failure of the EAC sensor, it can be replaced once. If the EAC sensor fails again, it must always be replaced together with the radiator.
The EAC sensor continuously transmits a signal to the engine control module. If an uncoated radiator without an EAC sensor is installed, the ECM will illuminate the check engine lamp."

http://www.e90post.com/forums/showthread.php?t=654769