You don’t need one and I think the neck in the radiator is deeper so it won’t work. I think that’s the way my 47 is.

@clarence-w-forsythe @dennis-christianson Unless the radiator has been changed, there is no provision in the neck to make a pressure cap work. There has to be a seat for the spring loaded gasket to seal against.

The shop would not have been able to find a non-pressure cap from any local source. It is likely that they were unaware that non-pressure systems exist and thought that your original cap was broken or missing parts. The bad news is that they threw away your perfectly good original cap.

Mike

That was my thoughts as well, but checked it the other day, was low so added on water so brought it up to proper level. went for a ride and checked it again when I got home and it did seem to have a small amount of pressure, so maybe not original radiator. Did they may ones with the neck that would fit my car? Again Thanks. I enjoy the responses

Look to see where the overflow is on the radiator. If it's below where the pressure cap would seal, it's not made for a pressurized cap.

@clarence-w-forsythe Someone could have made a radiator to accommodate a pressure cap. Remove the cap and look onto the neck. There will/won't be a seat and that will tell the story. Tiny is correct. A pressurized system would have the overflow pipe between the cap and the seat.

Pressure buildup in a non pressurized system would indicate a plugged overflow pipe.

Mike