Packard Forum Index » Pre-War (1899-1942)

Sounds like a plan but let us know if he sends a different nut after the repair or what he suggests. Seems to me reusing the too large a nut you have now is a future problem when getting it back in the plate. If it comes back you might wind up needing to cut a slot in the plate anyway.

Typically for caged assemblies, like the temperature unit, the restoration guy will feed the tube through, then solder it as he is charging it with expansion fluid so it will come back to you looking like it does now. The nut on the bulb that holds it into the engine port is pretty much a fixed size that is determined by the retaining collar and its associated pipe thread...you dont get to choose, typically.

As I understand it the plate is not going because it still has the mechanical oil gauge mounted. Some of the modern aftermarket gauges have a standard size nut that threads into different size adapter bushing their sensor inserts into. Pick an adapter that matches threads in the hole in the head. If he solders on a modern bulb it may come back that way. If he reuses the Packard bulb, the sealing flange is recessed into the head quite a bit and a different or smaller nut may not be long enough to push the sensor flange against the machined sealing surface in the head opening. Been there, done that when I had to install a temporary gauge hook up on the 47.

I don’t know what will happen ..I can bore out plate hole if it comes down to it..the whole repair and complication seems nuts to me

So I did cut a slot on top of plate and eased edges to allow repaired unit to be re installed when it returns…the coolant from the head emptied when pulling sensor bulb.. I would like to pull car out of garage to work on some other tasks but worried about running engine without the coolant in the head..engine would run just a few minutes…is that ok or should I just wait till unit is back in?

I don't know the size of the gauge sensor hole that is in the head used on your car -- and it did vary -- but on my engine it was 5/8-18 which is a standard fine thread. A regular pipe plug was not readily available in that size but I found that an ordinary bolt with that thread and some teflon tape around it worked just fine for the period of time the engine did not have a sensor installed.

You might measure your opening and see what is available in plugs or bolts. Be aware there is a machined seat for a flange on the sensor to seal against located at the rear of the opening so with whatever you use for a plug do not thread it in far or hard enough to damage that seat. Would also be a good idea to keep an eye on the engine temp by some other means if you are going to have it idling a lot of the time.