Oil Temperature Sensor

[steve meltzer]

As one of my recent threads documents, I recently pulled the engine on my Kirkham 427 to fix a leaking rear main seal. The car is back on the road, but I don't think the oil temp sensor is working. It screws into the Aviad pan, and it worked before I started the job. Is there a way to test this? I guess you must pull the sensor (with a big $%^&^% bucket to catch the new oil I just put in) and maybe test the sensor (carefully) with a heat gun? Is the wire in the conduit prone to breaking? thanx steve meltzer

[lippy]

First I would check all connections. It is most likely that. If you need to check the sensor itself, drain the pan, pull the sensor, and put the tip in a pan of boiling water. Obviously it should read 212/100c.

[steve meltzer]

Thought about the pan of boiling water, and I'll check the connectors. I guess I could run a continuity check as well, once the sensor is out. Doubt it's the gauge or the connection there, but it could be just a coincidinc...wouldn't be the first time the most obvious answer ain't it at all. thanx steve

[olddog]

I never messed with an oil temp sensor, but the water and air temp sensors are a resistive temp device (RTD). You can look up on the net a chart of temp verses ohms (for water and air). I would guess the oil unit is the same as water, but be ware of assume. You really do not have to heat it to test it. It is at some temp right now and it should read some ohms that would match that temp.

Likewise you should be able to connect a known resistance to the wires to test the gauge and wires.

I'm not sure if they are designed to rely on engine ground to work. If one wire, it definitely is. Since you had the engine in/out, make sure you have a good ground. Also coating the threads with massive amounts of PTFE tape may insulate it from ground. So while your at it make sure the pan and sensor are grounded.

[steve meltzer]

Thanx old dog, i'll check that after the holidays. Does anyone know the part number or source for this sensor? Best to call Kirkham or Southern (they built the engine) or ?? thanx. s

[Mongoose930]

Hi Steve,

What type of gauge is this? Is it a Smith's mechanical gauge or a Kirkham electrical gauge or something else? If it is a Smith's mechanical, it will have coiled wire sheathing - see link to Nisonger who could repair this gauge if it is broken: Nisonger Instruments :: the exclusive Smiths U.S. Warranty & Service Center since 1949

If it is an electric Kirkham gauge, I would start with Kirkham.

[steve meltzer]

it's an Autometer, and I think it's mechanical. if so you must buy the gauge with the sender and its wire, as they don't sell anything separately. thanx s

[DanEC]

How long have your run your engine since you reinstalled it? These cars take a long time to warm the oil to the point it will even register on the gage. If you have remote oil filters and an oil cooler it takes even much longer. Have you given it an opportunity to get hot?

[steve meltzer]

Good point and I thought about that. I'll run it a bit longer as it was pretty cold on my way to work in the beast this AM. The unit is mechanical and there are no wires, it's really a strain gauge as I understand it. No grounds, etc. s

[undy]

oh, we finally figured what type of gauge/sensor it is... OBTW, the connecting "wire" is not a wire, it's a capillary tube.

[Gaz64]

If it has a copper tube surrounded by a spiral protective coil, then the line has ruptured or has been damaged in some way, and the fluid within the assembly has leaked out.

Did you smell an "alcohol" type odour?

[patrickt]

Originally Posted by Gaz64

Did you smell an "alcohol" type odor?

Uhhhh, around here you could ask that on about 90% of the problem threads....

[steve meltzer]

Yep, it's a capillary tube. Not one electron trying to find its way home! Good pdf explaining how it works on the Autometer website. Now the mea culpa: Despite a spirited 5-6 mile drive, the oil hadn't warmed up enough to move the gauge. It worked, as it should, on the way home...iatrogenic problem solved. thanx again guys. steve