oil pressure sending unit decode

[resto4u]

Does anyone know what this oil pressure switch belongs to? 3918895 Gr.3.875 It has two prongs. Could not find it in my GM books. Thanks,Roger

[resto4u]

Can anyone with a old GM parts book tell me it's application? Thanks,Roger

[Nova Research Project]

resto4u,

I just got back to my books. Group 3 is exhaust and fuel system related. There is no listing for 3.875. Are you sure of the group?

[Nova Research Project]

resto4u;

OK I found it in the 1972 Truck catalog P&A 31S:

3.875 SWITCH-LENS-TEE-WIRE., Assy. Governor Overspeed Warning.

3818895 vacuum switch

58-64 Ser. 60-80
65-68 Ser. 60-80 (8 cyl.)
60-70 Ser. 50-80 (8 cyl.)
71-72 All (8cyl.)

[resto4u]

Thanks for your reply, still not sure what that would be. Never heard of that part before, does look like a oil sending unit. speed governor?????? Roger

[Nova Research Project]

I know that trucks and busses had an over speed light that lit when the truck passed a certain speed. This was different than the speed governor that kept you from exceeding a certain speed.

I believe this is a vacuum driven switch that cut in once a set speed was reached which turned on a light or buzzer to warn the driver.

[resto4u]

speed warning on a truck, cool.... /ubbthreads/images/graemlins/rolleyes.gif