if you were going to put an oil temp gauge in...

Where would the sending unit go? This is going to be an electric gauge in place of my broken Auto Meter clock.

 

Oil pan is where mine is located.

 

prolly the best place would be on the engine oil pan, but that means modifying the pan for the fitting and welding.
Short of that, maybe teeing into/off of the oil pressure sending area, but it prolly won't be as accurate temp wise.

 

Here is the story, I have 5 gauges right now including a clock. I have a clock on my stereo and the clock doesn't work. In its place I was looking for a new gauge and the oil temp gauge seemed like the best one sticking with my chrome Auto Meter gauges.

As far as reading the same temp as the water, it might very well. I don't know how different the two will read.

 

i've thought about about adding one to the transfer case, rather then the engine.

I think a vacuum gauge would be handier than oil temp anyway.

 

That is a good idea too.

 

Vacuum gauge, definitely. Oil temp for an automatic or a VW, as mentioned.

 

Depends.

Oil temp is one of the most important things with an engine. Oil temp needs to be above 212 degrees in order to boil out moisture (which causes sludge, especially if engines don't get hot enough) but below 275 or so in order to not cause premature oil breakdown. The oil is what transfers heat from the reciprocating parts to the block. It is then the waters job to transfer the heat out of the system via the radiator. Oil temp is really important in high speed, high rpm applications (road race, NASCAR, little motor wound up on the highway) but not so important in a low rpm environment.

The vacuum gauge is a great tuning tool that lets you monitor for vacuum leaks and idle mixture adjustments, but the oil temp is a more vital instrument.

Our water-cooled VW had an oil temp gauge and the owners manual said that when it got in the red to slow down until it cooled off. The 1.8 liter motor turned about 4500 rpm at 75 mph, but unlike an F or L head, would do that all day provided oil temp was controlled.

 

doodads geegaws

Maybe someone aught to go "all the way" with gauges.
Imagine the possibilities!

Voltage
Amperage
Engine coolant temp
Engine Oil pressure
Engine oil temperature
Engine vacuum
Power steering pump temperature
Power steering pressure!

Transmission oil temperature
Transmission oil pressure (automatic)!

Transfercase temperature
Differential temperatures (front and rear)
Compressed air pressure

There are probably a few more I didn't think of. Imagine meeting someone on the trail, and your dashboard looks like something from a Convair 400 !!!

-Pat

 

I have one on my diesel engine.

 

Yes they are different. Liquid Cooled, Antifreeze runs about 160* - 180*, Oil temp 210* -230* . It will run higher than that on hot days and pulling a load. Those oil temps are before the oil cooler. You can use an oil cooler to help cool the engine, but you have to be careful not to over cool or restrict the oil.

 

It is my understanding that oil temperature must be at least 180 to burn off condensation and acids that form in the oil, Looks like a 160 degree engine thermostat will just let the oil get hot enough to accomplish this. I know in the colder climates the F-Heads run better @180 but here for me 160 has no ill affects so far.

 

I do not think you can related what your coolant temp is to what your oil temp is. The coolant can only carry so much heat away. The oil temp in my truck is higher than the coolant temp. The systems are separate. The oil is directly exposed to higher internal temperatures, mostly combustion, either spark or compression. The coolant is only exposed to the heat radiated off the block, head, intake, etc after the combustion event.

 

As I noted above, you need to get your oil temp to at least 212 deg f, which is the temperature that water boils. This gets the liquid condensation turned to vapor where it can be removed by the PCV system.

The waters primary job is to remove heat from the engine block that has been transferred by the oil. As I had kind of laid out before, the oil is the one doing the real work. The oil is the one where it is most important to maintain temp, it's just that the water is the first system to overheat (usually, but not always) if the oil level is correct and the pump functioning.

But obviously the OEM's have just put water temp gauges in most vehicles since that is easier for people to monitor and understand. Most Diesels have thermostatically controlled oil coolers to keep oil temp in the ideal operating range.