Value-oriented Replacement of Yanmar Oil Pressure Sender

[vertigo]

Hi, all. I recently acquired my first Ranger Tug, a 2012 R-29 @900 hours, Yanmar 6BY2-260 powerplant.

The top item on my squawk sheet was to isolate and resolve an intermittent anomaly in the oil pressure readings whereby the Yanmar engine instrument panel would sometimes show blank oil pressure, and sometimes read implausibly-low pressure upon throttle reduction to idle from cruise power.

Upon studying various threads on this forum I learned that the OEM oil pressure sender is prone to failure and is pricey at approx $275/each, so I decided to set myself to figuring out the source and cross-reference for these pesky overpriced units. (On review of the parts lists for the 4BY and 6BY engines, I found that the same oil sender part number is used, so this information should be useful to owners of either engine.) After removing and inspecting the stamped markings on my original OEM sender, I was able to make a positive identification of its origin, and of a much less expensive replacement unit that remains 100% compatible with the original Yanmar instrumentation.

The oil pressure sender is a fairly standard (in Europe and Asia, at least) VDO unit, bearing the ID marking "32/6" which identifies it as a floating-ground sender without warning contact, 0-10 bar pressure range, 10-180 Ohms, with M14x1.5 mounting threads. The VDO part number for this unit is 360-081-032-006C. You can order this sender from European suppliers for approx. 55 Euros.

If you'd like a convenient replacement for this unit that can be obtained readily from US suppliers, then you can order a VDO 360-043 (ID stamped as 32/14), which is the same unit as the original, but with a 1/8"=27 NPTF mounting thread.

$36 at Fisheries Supply:
https://www.fisheriessupply.com/vdo-gau ... to-150-psi
Sku# 431477.

In order to use this sender in your BY-series engine, you'll need an inexpensive thread adapter: Male M14x1.5-to-Female 1/8"-27 NPTF. The adapter threads into the engine port, and the new sender threads into the adapter. This sender will work with your original instrumentation without any modification.

https://www.amazon.com/Female-Sensor-Ad ... 291&sr=8-6

At these prices, you can replace your intermittent or inop OEM oil pressure sender and stock up another half-dozen spares for less than the cost of one unit packaged in a spiffy Yanmar cardboard box.

Happy tugging!

 

[knotflying]

Great find, but have a question. The picture on the sending unit shows only one stud for electrical connection. The Yanmar has two, with one wire going to (I seem to remember) the paddle wheel ground lead, per the service bulletin. What would one do with the other wire that is supposed to connect to the unit?

 

[vertigo]

Great find, but have a question. The picture on the sending unit shows only one stud for electrical connection. The Yanmar has two, with one wire going to (I seem to remember) the paddle wheel ground lead, per the service bulletin. What would one do with the other wire that is supposed to connect to the unit?

The picture that first appears on that page is not representative of the exact unit. But, when you select the thread size (1/8-27 NPT) and ID Stamp (32/14), then the photo changes to the correct version which has two posts.

It's also available on Amazon for $49 with free shipping:
https://www.amazon.com/VDO-360430-150-P ... 963&sr=8-1

 

[Salty7]

Thanks for these part numbers! Fortunately, I haven't had to replace my sender yet but expect I should have one in the parts box for when the original fails. Where is the sender located on the 4BY2-150 and is there room to install the alternate sender with the thread adapter?

 

[Brian B]

On the 4BY-2 150 and 180 the sender is under the starboard engine cover. It is on the very forward part of the engine right on top of it. Easy to access once the covers are removed. The port engine cover needs to be removed before the starboard cover can be removed. Not sure how much clearance there is between the sending unit and the cover. You could always cut a hole in the cover if needed.

 

[scross]

I purchased my Yanmar oil pressure sensor thread adapter here:
https://www.hoyetractor.com/PROD/OGA-1.htm
I used some blue loctite to secure the adapter to the VDO sensor. The thread adapter only adds a bit to the overall length of the sensor. By using regular nuts on the terminals and a bit of shrink wrap to secure the wire leads instead of the supplied tall knurled plastic nuts you should be able to get the assembly to fit under the engine shroud. My clearance length measurements were made using my old dead Yanmar oil pressure sensor.
Haven’t used this assembly in the engine yet but it’s ready to go in my spares box if needed.

 

[Salty7]

I thought the sender was under the cover, thanks for confirming that Brian. My recollection is that it's very tight under there. Al can you give me the overall length of your assembled part with the thread adapter? Next time I go down to Kiki I'll try to measure the space available under the cover and let you all know if it will fit without modifying the cover.

 

[scross]

Tony,
The boats in the driveway with 4” of snow on it right now. Will measure the VDO oil pressure sensor for you once I can get at my parts box in the cockpit locker!

 

[vertigo]

I purchased my Yanmar oil pressure sensor thread adapter here:
https://www.hoyetractor.com/PROD/OGA-1.htm
I used some blue loctite to secure the adapter to the VDO sensor. The thread adapter only adds a bit to the overall length of the sensor. By using regular nuts on the terminals and a bit of shrink wrap to secure the wire leads instead of the supplied tall knurled plastic nuts you should be able to get the assembly to fit under the engine shroud. My clearance length measurements were made using my old dead Yanmar oil pressure sensor.
Haven’t used this assembly in the engine yet but it’s ready to go in my spares box if needed.

That adaptor works well, but there are also lower-profile adaptors to be had, with no modification to the engine cover needed on my 6BY2-260, though I eliminated the clearance concerns altogether when I added fittings to relocate the oil pressure sender to a tee block mounted off the engine on a bulkhead to isolate the sender from vibration and heat fatigue, along with a steam gauge to provide real confirmation of the actual oil pressure underway.

All the parts needed for this modification are readily-available from Pegasus Auto Racing.
https://www.pegasusautoracing.com/docum ... =TECH00129

Some will no doubt recoil in horror at the thought of departing in any way from Yanmar original equipment specs. But, when Yanmar stopped providing warranty coverage for your engine, you became that engine's Chief Engineer.

Carpe Navis!

 

[Salty7]

Thanks Al, I have the same snow challenge here, about 14" but it is slowly melting. No rush, whenever you get to it is fine.

 

[scross]

The stock Yanmar oil pressure sensor is 3 1/8" imn length overall. The threads take up 7/16" in length so the part of the sensor sticking out of the female port is 2 11/16".
My thread adapter is 15/16" length overall. The threads going into the port are 7/16" in length.
With the thread adapter on the VDO economy sensor the overall length is 3 5/8" but that is with the stock knurled knobs. With standard nuts instead of the knurled knobs the overall length is 3 7/16". The VDO sensor height sticking out of the port would be 3" even.
So, the VDO sensor with the thread adapter is 5/16" taller than the original Yanmar sensor. Based on my measurements earlier when I replaced the Yanmar sensor with another Yanmar sensor, I think it will fit without modifying the engine cover plate. If I needed to modify the cover plate I think I would just drill a 1 1/2" hole in the plate for clearance and call it a day.

 

[vertigo]

The stock Yanmar oil pressure sensor is 3 1/8" imn length overall. The threads take up 7/16" in length so the part of the sensor sticking out of the female port is 2 11/16".
My thread adapter is 15/16" length overall. The threads going into the port are 7/16" in length.
With the thread adapter on the VDO economy sensor the overall length is 3 5/8" but that is with the stock knurled knobs. With standard nuts instead of the knurled knobs the overall length is 3 7/16". The VDO sensor height sticking out of the port would be 3" even.
So, the VDO sensor with the thread adapter is 5/16" taller than the original Yanmar sensor. Based on my measurements earlier when I replaced the Yanmar sensor with another Yanmar sensor, I think it will fit without modifying the engine cover plate. If I needed to modify the cover plate I think I would just drill a 1 1/2" hole in the plate for clearance and call it a day.

Excellent info! In my case I didn't bother taking height measurements, but merely checked for interference with a bit of putty over the top of the knurled nuts. If I needed extra clearance, I would probably cut the sensor's top posts shorter and use shorter nuts instead of the taller knurled nuts (as you described above). But, with my mod moving the sensor off-engine with a braided stainless oil feed line, that concern becomes moot.

 

[Salty7]

Al, thanks for taking the time to measure all those parts. I went to Kiki today and took a good look at the clearance under the cover. I was able to pass a 1/2" OD object between the top of the original sender's knurled knobs and the metal engine cover with room to spare. So, there is at least 1/2" of clearance, it's actually almost 3/4". I believe the less expensive sender will fit, no problem, with the thread adapter.

Vertigo, thanks for sharing the remote braided line idea, I am sure it works but it does introduce another possible failure point, the braided line itself. Oil senders do commonly fail on diesels because they get vibrated to death but they don't spray crankcase oil under pressure when they fail, a flexible oil line will make a horrific mess if it fails.

I was able to see the connectors on my original oil sender well today with a light. They are quite green/blue with corrosion, I made a note to self to clean them up and use some dielectric grease there, the ring terminals are not sealed at all from the factory.

 

[vertigo]

Al, thanks for taking the time to measure all those parts. I went to Kiki today and took a good look at the clearance under the cover. I was able to pass a 1/2" OD object between the top of the original sender's knurled knobs and the metal engine cover with room to spare. So, there is at least 1/2" of clearance, it's actually almost 3/4". I believe the less expensive sender will fit, no problem, with the thread adapter.

Vertigo, thanks for sharing the remote braided line idea, I am sure it works but it does introduce another possible failure point, the braided line itself. Oil senders do commonly fail on diesels because they get vibrated to death but they don't spray crankcase oil under pressure when they fail, a flexible oil line will make a horrific mess if it fails.

I was able to see the connectors on my original oil sender well today with a light. They are quite green/blue with corrosion, I made a note to self to clean them up and use some dielectric grease there, the ring terminals are not sealed at all from the factory.

I agree that a failure the remote oil line would be messy, so I ordered a high quality braided stainless hose rated for several hundred pounds of pressure. Since it is flexible it should outlast the rigid oil lines already on the engine, and these are frequently used in racing engines that take much higher stresses than mine ever will.

Ditto on the sensor clearance: I measured 3/4" space above the original.

 

[scross]

I used an almost identical remote oil pressure sensor from Summit Racing when I installed the IO-360 engine in my airplane. The same braided hose went about 12” from the back of the engine to the firewall. Lots of engine vibration (which can result in sensor failure) relative to the firewall. Never any issues with that arrangement. You just need to find a good place to mount the sensor to if you go with the remote set up.

 

[vertigo]

I used an almost identical remote oil pressure sensor from Summit Racing when I installed the IO-360 engine in my airplane. The same braided hose went about 12” from the back of the engine to the firewall. Lots of engine vibration (which can result in sensor failure) relative to the firewall. Never any issues with that arrangement. You just need to find a good place to mount the sensor to if you go with the remote set up.

Roger that! I see we share a common background of messing around with customizing fault intolerant propulsion systems in experimental aviation. Mine is mostly in the area of rebuilding and customizing former military aircraft. I've had many things fail in flight, but never a braided stainless oil pressure line.

An additional benefit to mounting the oil pressure sensor on a remote line is that you can test or replace it easily at any time without removing covers. I'm even thinking of adding a redundant secondary oil pressure sensor on that line with a switch so that I can cycle between sensors as desired, or to run another gauge independent of the Yanmar instrumentation. There's no such thing as too many gauges on a panel, right? 😉

 

[Salty7]

I don't want to hijack this thread but I'm a pilot too, who would have known it would take three pilots to figure this one out? Thanks for sharing all this info.

 

[vertigo]

I don't want to hijack this thread but I'm a pilot too, who would have known it would take three pilots to figure this one out? Thanks for sharing all this info.

Makes perfect sense: we aviators share an obsessive intolerance for inoperative engine instrumentation, and an unshakable belief in our ability to engineer improvements. 😉

 

[vertigo]

I used an almost identical remote oil pressure sensor from Summit Racing when I installed the IO-360 engine in my airplane. The same braided hose went about 12” from the back of the engine to the firewall. Lots of engine vibration (which can result in sensor failure) relative to the firewall. Never any issues with that arrangement. You just need to find a good place to mount the sensor to if you go with the remote set up.

Here's how I initially installed mine so that I can easily see the steam gauge when I open the engine hatch:

 

[NorthernFocus]

...Some will no doubt recoil in horror at the thought of departing in any way from Yanmar original equipment specs. But, when Yanmar stopped providing warranty coverage for your engine, you became that engine's Chief Engineer...

Well said. Though in fairness there is probably a statistical correlation between willingness to go there and having the necessary skill set to do so. Then there are the legal arguments...

Regardless of which engine manufacturer you're dealing with everything but the engine core is likely from a third party supplier. I'm all for companies making profits but it's a bit much when they are tagging on 3x, 5x, 10x markups versus other sources for the same parts. The most extreme case I've personally run across was a small fan motor for a Wallas stove. Wallas wanted $60 for it and I found the same part on-line for just over a dollar. Yes, one USD. Shipping cost more than the part.