Another sender question

[Quickstep192]

I’m working to upgrade my Yanmar 2YM15 to an actual gauge for water temperature. 
 

The new sensor that does temp and alarm is about 1/2” longer than the original. I’m wondering if the additional length will interfere with the operation of the thermostat. I don’t want to improve one thing and screw up another. 
 

Also, would the fitting on the other side of the thermostat housing be a good (better) alternative location?

 

[El Borracho]

There are gauges that contain the alarm switch. Eliminates the extra sender. 

 

[Quickstep192]

My bad. The new (longer) sender does both the gauge and the alarm. (It has two contacts) I’m just wondering if it goes in too far. 

 

[Quickstep192]

The oil pressure sender appears to be a tapered thread. I’m basing this on the fact that there’s no sealing washer on it, it just threads into the block. It’s really hard to access and the new, larger diameter sender does not fit in the confined space the old sender came out of. The old sensor can be removed with a 15/16 deep socket. 

The water temperature sender is a parallel thread, but it’s not 1/8. 
 

Here’s a picture of the water temp sender with a gauge on it.

 

[Quickstep192]

Whoa! You’re scaring me! 

It’s my understanding that the oil sensor is 1/8 BSPT. The BSPT is approximately 10mm (9.7mm), but it’s my understanding that the oil sender is a tapered British pipe thread, not a metric bolt thread. 

Someone please straighten us out before I start trying to put stuff together. 

 

[Plumbean]

Page 198 of the Service Manual on the 3YM30 says the water temperature sender is M16 x 1.5.  My guess is that it is the same for the 2YM15 but worth checking that.  For some reason the specs on the oil pressure switch are not in the Service Manual.

 

[Plumbean]

Page 198 of the Service Manual on the 3YM30 says the water temperature sender is M16 x 1.5.  My guess is that it is the same for the 2YM15 but worth checking that.  For some reason the specs on the oil pressure switch are not in the Service Manual.

Just realized my Service Manual also covers the 2YM15, so looks like M16 x 1.5.

 

[Quickstep192]

Checked out the engine today, there does seem to be room to fit a 'T' to add an O/P sender, such as:

https://www.pegasusautoracing.com/productdetails.asp?RecID=32021

which is available with different ports, giving a choice of senders.

There doesn't seem to be room to do the same thing for W/T as a 'T' would foul the alternator and exhaust hose (and possibly read a lower apparent temp?), so maybe either a combined sender/switch, or use the spare port on the other side?

If you're able to get a 'T' onto/into to port for the oil pressure sender, you're a better man than I. I'm trying to fit a nipple with a 45° elbow on it and having clearance issues. As I try to tighten it in, the elbow is hitting the oil filter housing. I found stainless steel nipples from McMaster Carr that are BSPT on one end and NPT on the other. I'm trying to combine that with a 45° elbow that will make the fitting turn aft to make room for the big sender. But, because things are so tight in that area, even if I solve the clearance issue, I'm having trouble figuring out a way to get a wrench on it. 

The adapter you shared from Pegasus is a 16mm fitting and wouldn't fit the oil pressure fitting. They do make a BPST to NPT adapter, but it's aluminum. 
 

The water temp sender is easy in relative terms. You don't need to add a 'T' for the water temp sender. There's a combination sender from AC/DC Marine that fits in the existing water temp port without modifications. The probe is 1/2" longer than the original and I thought it might interfere with the thermostat, but it doesn't. You'll need to get a new copper crush washer from Yanmar to install the new sender. 
The connectors on the new sender will end up close to the alternator bracket, so make sure they're well insulated. 
By the way don't be a dummy like I was - drain the anti-freeze before you remove that sensor. 

https://acdcmarineinc.com/shop/marine-engine-sending-unites-switches/temperature-senders/marine-water-temperature-sensor-m16-x-1-5-95c-alarm/

I'm keenly interested to hear about any solutions you or anyone) come up with for the oil pressure sender. The dual oil pressure sender (see pic) is considerably larger than the idiot light switch and the space around that fitting is really confined by the Oil Filter housing and the Injection pump. In my case, that is further encumbered by limited access to the engine. Also, I've been advised to keep the extension short and avoid soft metals to minimize metal fatigue from the engine vibration of a 2cyl diesel. 
At this point, I'd pay a bunch for a combination sender that fit in the original space. I might even be content with a sender that only did pressure and no alarm if it fit.

Please keep me posted on your findings and I'll do the same.  

 

[Quickstep192]

Here’s a picture of the KUS water temp sender/water temp alarm sensor in place.