Temperature sender ID

oilleaker1 · Post by **oilleaker1** » Fri Jan 23, 2015 5:54 pm

I have two senders # 7389566. One is SW and the other is AC. Are these for the 120-240, or the 60 -260 Temp. gauge? All 24 volt stuff. I appreciate any help. thanks, John

4x4M38 · Post by **4x4M38** » Fri Jan 23, 2015 8:07 pm

ORD 9 G-740 shows these senders for the M38.

Wes' photo pages on gauges shows the M38 temperature gauge
as 60-260, both AC and Stewart Warner.

Hope this helps.

Brian

keats · Post by **keats** » Fri Jan 23, 2015 9:21 pm

the senders should be stamped for the temp range gauged for

60lb or 120 lb

oilleaker1 · Post by **oilleaker1** » Sat Jan 24, 2015 6:45 am

The oil pressure sender is marked, but not the temp. sender. I can get both of my gauges to operate to full reading by grounding. I have Bob W's post about how to check all military gauges, but it doesn't ID by # which is which. My ohm meter says when heated the senders resistance changes, but I cannot accuratly heat water bench test wise and then hook up all the wires. The instuctions give resistance readings at different water temperatures, but it would be easier to install them in a finished engine and test them than bench test. My goal is to install a good sender in my block now. I'm not ready to run the engine yet. Both of my senders are original Douglas type which are correct for one of the two gauges. I've seen them ask $ 70.00 for these. Since I have both temp range gauges, and two of the same number senders, which gauge works with my senders is the question. John

oilleaker1 · Post by **oilleaker1** » Sat Jan 24, 2015 7:00 am

So , Brian, the 60-260 was the only range the M38 used, and the 120-240 is a M37 gauge? That would help narrow it down. John

oilleaker1 · Post by **oilleaker1** » Sat Jan 24, 2015 7:15 am

News Flash! Ebay had gauges and senders for sale. Brett Mullins listed the correct type by ordinance # for my 60-260 gauge with the external resister like mine. He says that sender only works with that gauge . The other senders I have are not compatable with it. I'm not sure which ordinance book lists my other senders, but they are obviously for later units. Not sure if they will work with the 120-240 gauge, but I ordered the right sender for my early gauge since the gauge is mint. M38's are different critters for sure. John

4x4M38 · Post by **4x4M38** » Sat Jan 24, 2015 9:24 am

Hi John,
It looks to me the 60-260 is the only range temp gauge used. There was a later change to the oil pressure gauge if I read right.

Yes, RJ Fitzpatrick has the original temperature gauge with resistor, and Brent Mullins is advertising the original sender for that gauge. Wes could go into great detail on how Ordnance numbers and suppliers and repair personnel figured all of that mess out.

I'd like to see a 1951 ORD 9 G740 parts list. The one on line here is 1955.
Not that it matters to motor pool folks, as the guys probably used what they had on the shelf. But it might shed some light on original production items as delivered. There are two senders from AC listed on the 1955 version. The page from the 1951 version Brent shows on his Ebay auction only lists one. AC-1512245.

Take care,
Brian