Firstfives.org

I purchased a 1978 530i a few months ago and it's been sitting in my back yard ever since. I have not yet saved the funds to get it on the road. I am unfamiliar with most of the mechanical workings of the engine, and I was wondering if there was a surefire way to tell if this 530i does indeed have a thermal reactor installed. The dash light is illuminated, indicating that the reactor needs to be serviced, but I'm not sure if a reactor is present. I was told by the previous owner that the engine had been swapped out and I'm not sure if the reactor was taken out. Is there a way to tell if there is a thermal reactor present without taking the engine apart?

A thermal reactor is kind of an exhaust manifold, except different. A conventional exhaust manifold is cast iron. A thermo reactor is kind of like a tin can with cast iron flanges. It also has a smog pump with air injection into it. The first image is a thermo.



The next a manifold.



You just have to look at it to tell, it could have been left in place or replaced with manifolds.

This is what the reactors look like. Note the smaller diameter air pipe running on top of them.

By the way, the service light is turned on based on mileage and has nothing to do with the condition of the thermo-reactor (if you have one). What I mean is that there is no sensor on the reactor, just a mileage based box that ties the warning light to the speedo cable. There should be a reset button on that box, which is in line with the speedometer cable and can be seen under the car.