Temperature gauge sending unit nut size

[iowa51]

Won't bore you with the details but anybody know the wrench sizes I need to remove the temperature sending unit from the block of a 218? If I remember correctly I think it is 2 nuts, one threaded into the other on my car anyways.  I would check my own car but at the moment I am several hundred miles away from it. 

[Plymouthy Adams]

yes you have a bulb base that is nutted and threads into the head....then you have the bulb gland nut (bit smaller) that screws into the bulb base.  BE CAREFUL if you gaug is still a working unit as the bulb will rust fast to the base and often the result is the twist of the capillary tube to the point you will break the seal.  Wrench sizes, can't say off the top of my head but common SAE. As the base nut is larger than the gland nut a common full set should suffice.

Edited September 4, 2023 by Plymouthy Adams

[iowa51]

35 minutes ago, Plymouthy Adams said:

 BE CAREFUL if you gaug is still a working unit as the bulb will rust fast to the base and often the result is the twist of the capillary tube to the point you will break the seal. 

 

Where I am staying at the guy has a limited tool chest. I plan on going to Menards, Harbor Freight... and try to find an correct sized flare nut wrench(s) that fits to help with removing it. I have a set at home so I don't want (or need) to buy a whole set.

[Plymouthy Adams]

Facts now in evidence......lol  

[Los_Control]

What I have on my gauge end side is a square nut & is 5/8" .... you wont get a flare wrench to fit a square nut.

The insert going into the head is brass ..... 3/4 is to small .... 7/8 is pretty loose. .... Old brass that is wore out? Maybe .... or they did have some strange sizes back then.

 

Pretty sure I just used a quality crescent wrench to remove mine .... maybe even a pipe wrench? I do not remember but it came out with no fuss.

 

Not sure why you want to remove it .... if you have a limited amount of tools available .... you may want to wait until you get it home where you have more tools to work on it?

 

Just not seeing why you would want to remove it when you are not prepared for it .... could turn into something bigger then planned on.

[Dave72dt]

There must be someone where the car is that could slip a couple of open end wrenches or a caliper on them and give you the size.  I'd like to say 5/8 and 7/8 but I don't have one to measure.  I'd stay away from crescent wrenches if I could.  They're the best tool I've ever found for rounding off nuts and bolts and taking the hide off knuckles.

[iowa51]

21 minutes ago, Los_Control said:

What I have on my gauge end side is a square nut & is 5/8" .... you wont get a flare wrench to fit a square nut.

The insert going into the head is brass ..... 3/4 is to small .... 7/8 is pretty loose. .... Old brass that is wore out? Maybe .... or they did have some strange sizes back then.

 

 

Thanks. 

 

21 minutes ago, Los_Control said:

Not sure why you want to remove it .... if you have a limited amount of tools available .... you may want to wait until you get it home where you have more tools to work on it?

 

Just not seeing why you would want to remove it when you are not prepared for it .... could turn into something bigger then planned on.

 

The car is in a salvage yard several hundred miles away from where I live as I am here visiting a relative and my tools are at home.  The car body is junk but the instrument cluster is in good shape so I would like to grab it before someone else does as it may be several years before I am back here again

Edited September 4, 2023 by iowa51

[Los_Control]

Just now, iowa51 said:

The car is in a salvage yard several hundred miles away from where I live

That makes sense ..... to be fair I have little hope the temp gauge will still work when removed ..... something that old is notorious for leaking when messed with.

If yours does work it will be a small miracle.

 

There are several videos or instructions available on how to use a donor gauge to fix your original gauge. So all is not lost.

I'm only suggesting you do your best to save it, if it breaks .... oh well just have to fix it.

[iowa51]

3 minutes ago, Los_Control said:

to be fair I have little hope the temp gauge will still work when removed ..... 

 

For the $25 he is asking for the whole cluster I will take my chances. My current temperature gauge works, this is a spare to sit on a shelf.

 

If the engine still had the intake/exhaust manifold and a cheap price I would have seriously considered making a trip back here sooner rather than later, but it is already gone.

[andyd]

I'd squirt lots of WD40 or similar into the gland nut area, think positive thoughts & good luck..........lol.......andyd.

[Jerry Roberts]

Also , there is a welsh plug in the head directly over the gland bulb . If you remove the welsh plug it might help to remove the bulb without breakage . 

[Los_Control]

Sounds like a good deal, good on you for saving them from the scrap yard.

 

When I bought my truck the temp gauge line was cut in 1/2 non working ..... but the faces on the gauge were terrible and unreadable.

Then I got another set that is really nice condition, the temp gauge is complete but non-working.

 

So I installed a temporary modern gauge & works fine, it was only temporary and going to use it for a donor .... when I went to remove it, then it leaked & no longer works.

So I bought a new donor gauge from ebay, I did not pay attention and it was sent snail mail from India ... took 3 months to get it.

It does not read correctly and not a suitable donor so I'm still looking for another.

 

Just now, andyd said:

I'd squirt lots of WD40 or similar into the gland nut area, think positive thoughts & good luck..........lol.......andyd.

I'm just about out of positive thoughts on temp gauges   

[TodFitch]

1 hour ago, Los_Control said:

. . . So I bought a new donor gauge from ebay, I did not pay attention and it was sent snail mail from India ... took 3 months to get it.

It does not read correctly and not a suitable donor so I'm still looking for another. . .

The “mechanical” gauges work by having the bulb filled with ether which in the closed system pressurizes the capillary based on the bulb temperature. As long as your poorly reading Chinese gauge actually has ether in its bulb it should be suitable for use as a donor regardless if the dash unit works or not. The pressure in the line, as long as it is sealed, is simply a matter of the working fluid and physics. A crappy set of mechanical parts in the dash unit has more things that can go wrong.

 

There is the possibility (actually pretty likely) that the outside diameter of capillary tubing is different between your original and the donor but it is pretty easy to drill out some brass tubing to make a sleeve that will work.

[Los_Control]

Just now, TodFitch said:

There is the possibility (actually pretty likely) that the outside diameter of capillary tubing is different between your original and the donor but it is pretty easy to drill out some brass tubing to make a sleeve that will work.

Thanks Todd I agree 100% .... the new gauge I received is not a brass tube .... not positive but think it is plastic wrapped in some sort of high temp nylon braiding.

 

Just not suitable for a donor to solder to mine ..... something else we have to look for when buying a donor.