Sensorik fuer Oeltemperatur | Posts 16+

Hi,

@Jan6K
The ASV has a heat exchanger located underneath the oil filter.


but I still don't like the idea, because there would be some cables between the plastic and the hot oil pan.


I've been driving with the sensor attached to the drain plug for about 50,000 km, and so far, there have been no issues.
Problems. I once had a dipstick sensor in my first car, and it gave me endless problems.
prepared. It's been 15 years, though, so maybe they're better now.
If you're worried about the cable, there are actually several ways to protect it.
For example, replace plastic corrugated tubing with silicone tubing, or replace standard cable with a silicone hose.
'For example, I used the same corrugated pipe as the automotive industry, and luckily, ours...'
The company manufactures sensors for the automotive industry.

Hi Achim,

That would mean the temperature sensor on the oil filter housing would be pointless.

So, are the other two options ))?

Did you purchase a complete unit, meaning the sensor and display together?

I'm currently considering using a PT100 or PT1000 temperature sensor housed in a screw fitting for the drain plug.

Are there any experiences regarding quality and tightness? I'm sorry, I can't provide recommendations for specific types or manufacturers.

What dimensions are needed for the TDI? (I assume the dimensions are the same for all TDI models), and are there any issues with the length?

Best regards,

Jan.

I've been dealing with this topic for a while! Forget about the drain plug immediately if the oil pan is made of aluminum! Keyword: contact corrosion!!! Most of the sensors and their adapters are made of brass! The oil level dipstick is useless! The only true and reliable option is the oil filter housing! However, in my 96kW TDI, the oil pressure sensor occupies the only available space there. So, my parts supplier sourced a kind of Y-adapter from an Audi A6. You can screw the pressure sensor AND the sensor into it. However, it's not that simple for me either, because I have the long temperature sensor from EQUUS, so I had a custom adapter made at a machine shop. The VW Y-adapter costs about 35.- and the handmade one made of brass costs another 40.-. Not cheap, but it's good quality. Originally, on VW vehicles, the oil temperature sensors are always located on the oil filter housing.
There are even pictures of it online.

Greetings.

Hi,

Quote:

Forget about the drain plug immediately if the oil pan is made of aluminum! Keyword: Contact Corrosion!!!

And what about the copper ring between the oil drain plug and my aluminum oil pan?


Best regards, Rainer.

......nothing, if the oil pan is not made of aluminum, or if the ring is not made of copper .

VW does NOT provide a warranty in such cases!

Hmm, I've been using copper crush washers between the oil drain plug and the aluminum oil pan for years.
What comes standard with this?

By the way, the pistons are made of an aluminum alloy, they contain a steel piston pin, and typically there's a bearing bush made of a brass/bronze alloy in the upper connecting rod eye.
It won't be that wild, though. I think the claim about losing the warranty due to a copper sealing ring is a myth. Do you have any specific statements on that (a link or excerpt from an official document would suffice)?

I just remembered something: the oil line from the oil filter housing (aluminum) to the turbocharger is sealed with regular copper sealing rings. Therefore, I'm preemptively classifying your statement as "rumors and fairy tales."

Best regards, Rainer.

I cannot say exactly what the situation is. My 'expert' told me that VW uses screws and washers with partial coatings. Perhaps that is the answer to your question. You cannot always use the same metals, but VW coats them instead! Only can a sensor or an adapter be coated afterwards with difficulty .
'But contact corrosion is nothing new; it's an old problem! You can certainly try using a brass screw, and it probably won't cause any issues, but it COULD!' I'm not taking the risk!

Greetings.

I don't have to provide any information here either. These fairy tales are not my creation!

Hello,
Okay, from an electrochemical perspective, the issue of aluminum contacting copper, specifically concerning contact corrosion, is not a myth. (see, among other things, http://www.forges.ch/webthema/web_okt.htm#Kontakt).
The extent to which these boundary conditions at the oil tank (temperature, water content, etc.) are relevant will be determined by experience in each individual case.
Regards,
Max.

Hi,

Regarding aluminum/light metal and copper rings.
"I've been running engines with this combination for ages without ever having any problems. In the past, it was the air-cooled boxer engines from VW, and now it's an AFN engine in a T3 van with an aluminum oil pan from a JX engine."

Regarding temperature measurement:
The maximum temperature readings generally refer to a measurement taken in the oil pan. In my opinion, this measurement can only be accurately performed with a dipstick sensor, as this is the only way to ensure that the sensor is measuring the temperature of the oil itself and not the temperature of the engine block, the oil pan, or the surrounding environment.
I believe that taking a measurement in the oil filter flange is a very bad idea, because the amount of oil present there is very small compared to the surrounding metal. Furthermore, right next to it is the well-known oil/water heat exchanger, which will also affect the measurement.
The fact that VW themselves install oil temperature sensors in that location is not an argument for me; after all, there are many other known design flaws (or "victories of commerce") in these cars.

greetings
dieter

Hello Max & Mike,

That's true, but is contact corrosion actually relevant in this practical application?
The engine oil's job is to neutralize acids that are produced during combustion.
Engine oil is also not electrically conductive.

Best regards, Rainer.

Engine oil is also not electrically conductive.

That is not quite right

Sure, here is the translation of the text from German to English:

'Cu Gremlin'

Hm

Hi,

I've only seen that method used with an iron nail in a copper gutter.
Copper is more noble than iron... etc.
But why should aluminum react with copper?
I can imagine that with heavier use, copper and aluminum would wear down, but in this case...
For such "mundane" applications, I can't imagine such drawbacks.

Engine oil and conductivity:

It's probably like with water. The pure or distilled kind. Water doesn't really conduct electricity.
"Impurities" in the water conduct the electricity.

Greetings.
Thomas.

Hello,

Theoretically, the less noble metal dissolves, so in the case of copper and aluminum, it would be the aluminum.
In my opinion, this would only be practically relevant in cases of extremely severe contamination in the oil pan.

@Gremlin, well, enlighten me. I'm sure there are some metal salts and buffer solutions in motor oil. But does that affect the electrical conductivity?

Best regards, Rainer.

Engine oil and conductivity:
It's probably like with water. The pure or distilled kind. Water doesn't really conduct electricity.
'Impurities' in the water conduct the electricity.


yepp.

First of all, that, and I don't need to tell anyone what the TDI oil looks like...
In fact, the conductivity of the oil is also a parameter that is measured by the oil quality sensors.

Secondly, there is indeed the phenomenon of electrical erosion at engine bearings. For example, if the crankshaft has a different electrical potential than the bearing housing (e.g., due to corrosion of the grounding strap), even voltages in the single-digit volt range can be sufficient to break through the oil film due to the thin film thickness in the bearing. While this is less likely to occur in vehicle engines, it is occasionally found in generators (due to inductive interference from the generator).

CU Gremlin.