| These replacement switches are a one time only for your 78-83 z or zx. They may be more expensive than the aftermarket units, but the quality of these units is unsurpassed. If you're planning on keeping your z car, then these switches are the only way to go. We do sell the aftermarket less expensive brand, but we won't guarantee them. If you want that version then see the other listing. The original factory oil pressure sending units for all the z's from 70-83 were far from perfect. A lot of them started to give a bad signal after only being 3 or 4 years old. Many of them started leaking about the same time. They had a very high failure rate, as did all of the aftermarket brands. The aftermarket brands must have copied the original factory style because they too have a high failure rate, and give incorrect information to the gauge quite often. In 1984 Nissan released their newly redesigned oil pressure sending units which was a much needed improvement. To this day I have never seen that particular model of oil pressure sending unit fail on an L series engine. They still give an accurate reading after all these years, and I have yet to see one ever leak oil. Back in my dealership days, we use to replace a lot of them. I bought my first z new in 1978 and even that oil sending unit failed at about 55K miles. It had been reading a little inconsistant, and then it started leaking oil. By that time the new senders had come out on the market. I still own that car and that same sender works fine to this very day. That same style sender for the 78-83 also fits the 84 300 zx. On the 300zx I have seen this unit fail, only because it's located right next to the exhaust manifold, and the intense heat from the manifold cooks any oil switch. So far no one makes a heat shield for the oil switch on the Z31's, but they desperately need one. This particular sending unit uses a 2 wire system. The second wire is a safety circuit for the fuel pump and it's critical to use that circuit on any car with an electric fuel pump, if the car is designed with that style of safety circuit. Last updated 03/31/10 | 
