Oil pressure sender leaking-how to fix?

[RebekahsZ]

My sender is leaking at the crimp between the outer sheet metal housing and the inner sheet metal housing.  My question is this: should I try to clean it and apply epoxy to it, or try to get a radiator shop to fill the gap between the two pieces of sheetmetal with solder?

 

My original sender leaked at the same place, and so I bought a new sender-and it leaks too!  Its not a big leak, but its the only leak I have, so I want it gone.  I'd love to get your suggestions.

Edited August 4, 2014 by RebekahsZ

[240z72]

I'd take the new one back and have them exchange it. I've never had the Datsun ones leak. That's interesting that the new one dose too. I believe I have a few stock ones layen around. I'd give you one after I verify it works. If it gets to that.

[RB26powered74zcar]

I had the same leaking on my AutoMeter oil pressure sender. I replaced it with a new sender, with no leaking so far....

 

I recon it's a fairly common issue. Especially when you have a oil pump that puts out good oil pressure, especially when cold. 

[djwarner]

Since there is a rubber diaphragm under spring pressure inside, I would advise against adding heat.  

[Tony D]

This is a "replace" item, not a "repair" item.

[RebekahsZ]

There are two styles and the style I prefer is the harder of the two to obtain, so if you have a good source, throw it up for me please. There is a larger sender that has a spear-like connector; hard to find a female snap-loop wiring connector to attach to it. The smaller sender uses a simple loop on the wire and the sender has a little 9mm (the head is 9mm, the thread is more like 4-5mm) screw/bolt in the end that holds the wire on it. I have found the picture of the smaller sender in several catalogs and ordered it, then what arrives in the package is the large version that I can't get a wire on. Anybody got a reliable source for the small sender with the screw? I assume (we know what that does) that it is an earlier version that has been superseded in all the parts books? Probably cause the early part leaks-haha!

Edited August 8, 2014 by RebekahsZ

[Tony D]

It's a "Roadster Sender", people have been using those as replacements for the later units for years.

[RebekahsZ]

djwarner was right-the soldering killed the sender.  After soldering,  I could hear a rattle inside the sender, but I installed it anyway:  it did read oil pressure...sometimes.  So, with Tony D's help, I went looking for Datsun Roadster Senders.  Very hard to find.  Found a used one that looked pretty good for $38 plus shipping.  Found 2 units for $120 and $140, but the ebay stores for those guys were inop.  So, I bought the used sender and mixed up some JB weld and applied it to the crimp fitting, the base of the hex portion of the stem and I even JB welded it externally (so maybe I can get it apart later) where the adapter screws on.  The problem with the BSP to NPT thread adapter is that it isn't labeled in order to know if the adapter is BSP to NPT, or if it adapts BSP to NPT, in other words I don't know if the male end is BSP or NPT, nor do I know which the female end is-the facts are somewhat hidden by the English language.  So, I'm using JB weld to make up the difference between 27 threads per inch and 28 threads per inch (which I sure as hell can't count accurately on a stem that is of unknown length less than 1".  If no posts are added, you can assume that it worked and I'm not dripping on the track anymore.

[djwarner]

This raises another question that has been bugging me. My Series I has the original 140psig gauge and the sender was leaking when I bought the car. A trip to the local auto supply store sourced a compatible sender.

 

Later I found out that the original sender part number was superseded with the same part number as the ones found on Series II and later cars.

 

Still later, I found out that the shop instructions state to also replace the gauge with a 90psig when replacing with the superseded sender. This makes sense for the then modern model car, but sucks when trying to restore a 43 year old car and desire to keep the original gauge.

 

From what I can tell, the original sender was a 10 Bar sender (10 atmospheres or 145psig) and the replacement sender is a 6 Bar sender (87 psig).

 

So what readings do I get when I use a 6 Bar sender and a 10 Bar gauge?

 

I did find a modern 6 bar sender that had the following specs:

 

6-8psig  open circuit (this explains why our gauges go to zero when idling after a hot run).

15 psig - 50-79 ohms,

70 psig - 10-30 ohms,

90 psig - 8-22 ohms. 

 

I have no idea what the original sender specs were, but the 6 Bar specs seem pretty loose.

 

Does any one have specs for the 10 Bar sender?

 

Or better yet, does anyone know of a suitable sender from a different model/make? 

[RebekahsZ]

Sorry buddy, I'm a plug and play mechanic.  The new sender reads lower than my last one, but I'm gonna mark the new "normal" with a Sharpie and move on.