3ym30 oil sending unit

[Ram]

Before the pandemic I bought new gauges for my 3ym30 ,2003 model year yanmar
The the oil pressure sending unit that came with the new gauges does not fit.. seems to be the right diameter but the threads on it won't screw in, i'm wondering is the old unit metric?

[Compass790]

Originally Posted by Ram

Before the pandemic I bought new gauges for my 3ym30 ,2003 model year yanmar
The the oil pressure sending unit that came with the new gauges does not fit.. seems to be the right diameter but the threads on it won't screw in, i'm wondering is the old unit metric?

I dont know that engine but the oil pressure sender on our Yanmar is 1/8 BSP, your new sender maybe 1/8 NPT as that is far more common. Is their any info in the paper you got with the gauges, just wondering?. I'm assuming replacement sender is non OEM. You can get an adapter online with a search, be hard to find one otherwise I'd imagine but an auto supply place might be worth a shot or a place that does industrial instrumentation for piping..

[GordMay]

Yanmar, Volvo, Lehman use metric fasteners and fittings in their engines. Yanmar’s pipe threads are to Japanese Industrial Standard JIS B 0203, which is identical to British Standard, BSP, and DIN, which have a thread angle of 55° and 28 threads per inch in the 1/8-inch pipe size.
The U.S. Standard NPT has a thread angle of 60°, and only 27 threads per inch, in the 1/8-inch pipe size.
The two thread sizes are so close, that visual comparison is inconclusive. The threads might appear to make up, but they will not seal properly.

You could use your new sender, with an adapter [1/8" Male NPT to Female Japanese/BSP]
$8.69 ➥ https://www.hoyetractor.com/PROD/OGA-1.htm