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Hi...I've just found a dielectric constant measurement instrument at home that I'm planning to use to determine when to make the oil change.

I've done a test to the new oil (Castrol RS 10W-60) that resulted in a dielectric constant of 6, and now, after 1000 km. the dielectric constant is 9. This increment I think is due to the new oil mixing with rests of the old one (different kind), so if after several tests (say between 1000km.) it is still giving 9, then everything should be OK isn't it?

What I'm planning to do is to make oil changes after 10K km. provided that the dielectric constant doesn't increase in a certain percentage, but what percentage should I consider?

Any advise?

Thanks....from Chile

Tomás

PD: sorry about my english
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As far as I know,dielectric constant is only part of oil story. Even CSI (Oilview producer)recommend dielectric constant as a complementary tool for engine oil analysis, not a major tool. It is good to be as a last defense for industrial oil. (Not very sensitive ,but better than nothing). For engine oil, you need blotter test, crackle test(you can DIY),and ICP or RDE (takes a little money).

Regards,
I agree with Silkolene expert's opion. Dielectric constant tester is still valuable to screen out wrong oil, badly degraded/contaminated oil for some type of oil/application. My lab have one too. IMHO it is good for large number/less-critical/penny-budget industrial equipment oil(pump,fan,etc.), but engine oil application is not a right place for this kind of instrument.
That dielectric seems to be very high even for the new sample. Most engine oils have a dielectric of between 2 and 3. I believe dielectric can be used very accurately to determine when your oil needs to be changed, however it takes quite a bit of testing and research to be able to do so. Not only can you track oil degredation but you would also be able to see if you have coolant in your oil, which then lets you know you have even larger problems. One thing to keep in mind is the dielectric is related to the viscosity of the oil. So a straight weight oil is easier to read than a multi-weight oil (ie 15W40). Dielectric also varies with temperature. Just a few of my thoughts on the subject......
Thanks,
CCCOUS
By the value given by the instrument, I suppose that the scale is not the actual dielectric but a modified scale (Ranging from 0 to 40) to better distinguish the variation of the constant when compared to the new sample.

By the way the instrument is a Hoppy AN-OIL-IZER, very old but working properly I guess.

If I measure the sample always at the approximately same temperature (I extract the sample when hot and let it cool down), then the viscosity should always be the same when measured regardless of if it's a straight or multi-weigh oil shouldn't it?

Thanks
Tomás
Tomas,
Assuming your dielectric is read in somewhat of a controlled environment (ie Temperature) that should fix the viscosity vs. dielectric issue. However the larger task at hand is knowing exactly when the dielectric is at the point in which it needs to be changed. I have done a lot of research on this subject, and I have seen alot of different numbers out there, any where from a .2% change to a 15% change in dielectric. This is why it takes alot of testing and research to determine exactly when this dielectric reaches the point to where you can say your oil has degraded. I do not think you will get anyone to tell you what that percentage is, as that is the kind of info companies can sell.....There are a few oil quality sensors out there on the market that use dielectric to determine oil quality but like I said they already did the research and testing so that they can use that information to sell their product. If you do get this information from someone or some company feel free to share it!!!! Good luck.....
Gentlemen,
You might just as well base your oil change intervals by the color of your oil. Based on expert advice cited, your proposed analysis methob does not apply to engine oil. SUbmit a sample to a reputable oil analysis operation. YOur oil is not only an essential part of you engine system it is also an indicator of what is going on in that system. An oil analysis not only tells you if your oil is still up to specs applied to your particular vehicle. It will also tell you the condition of that system. trace metals and chemicals not originally present in the original formula will allow the analysis co. to make a very good educated statement on what is wearing out, leaking, or overheating in your engine. Dielectric in Motor oils is an extremely small bit of an overall well maintained preventative maintaince program.
Your question was "Can I rely on dielectric constant?" answer: NO, Rely on Oil Analysis.
Rand,
The test I do to my car´s oil is simply to evaluate the condition of it periodically. I´m currently using Mobil 1 5W-50 and doing changes every 13.000 km provided the condition of the oil remains stable or with a normal increasing tendency of the instrument´s reading compared to the condition when new.

I don´t know what the scale of the instrument actually means but I guess it's usefull anyway because if the reading is 6 with new oil, and after 1000 km it´s still 6 or maybe 7, then I conclude that the oil is in good condition because the increment as a percentage of the full scale of the instrument is very low.

Tomás
quote:
Originally posted by Hawk:
Gentlemen,
You might just as well base your oil change intervals by the color of your oil. Based on expert advice cited, your proposed analysis methob does not apply to engine oil. SUbmit a sample to a reputable oil analysis operation. YOur oil is not only an essential part of you engine system it is also an indicator of what is going on in that system. An oil analysis not only tells you if your oil is still up to specs applied to your particular vehicle. It will also tell you the condition of that system. trace metals and chemicals not originally present in the original formula will allow the analysis co. to make a very good educated statement on what is wearing out, leaking, or overheating in your engine. Dielectric in Motor oils is an extremely small bit of an overall well maintained preventative maintaince program.
Your question was "Can I rely on dielectric constant?" answer: NO, Rely on Oil Analysis.


Absolutely correct! Dielectric test is intended and reliable only for insulating fluids. I would never entrust fate of my equipment or a vehicle to a method easily affected by many factors which remain unknown to users of this method. If I would decide to be reckless, I would rather adopt “judging oil quality by its color” than rely on dielectric test. I am joking, because I find both approaches extremely laughable. However, everyone has a right to destroy their equipment the way they want it.
Oil may have different types of contaminants, some of them may increase the dielectric constant while the others may just decrease it. The combined effect may be nil i.e. no significant change in the constant of oil leading us to wrong conclusion that oil is OK.

Still if some relation can be established between dielectric constant and moisture or solid particles (Carbon and metal), it may give us some very cheap and good equipment to measure the cleanliness of oil.

MR CCCOUS! what are the results of experiments conducted by you, we are waiting for to hear from you. Can you write to me on prabhakar@klarol.com , we may discuss more freely.
Please understand that I am not trained in the electronic or chemical sciences. I am the son of one of the principles of the company that hired an engineer that worked with others that were trained. Their task was to come up with a tool that helped provide an indicator of the oil's state. My understanding of the target market for the An-Oil-Izer was fleets like taxi services and small truck lines that typically won't or don't go to the expense of an oil analysis. The testimonial responses from those types of companies was that they saw a great percentage savings from the cost of premature oil changes and extended engine life and fewer lubricant related repairs or problems. One of the most interesting to me was the use of the An-Oil-Izer to test the oil in air conditioning units on rail road cars. Small engines that run constantly for extended periods of time. Also the introduction of the An-Oil-Izer was about 30-35 years ago. One of the patent numbers is 3182255 and I think this is the first one. There was a later patent but I don’t think it made it into a product that was sold. Hopkins provided an An-Oil-Izer to Phillips Petroleum who tested a lot of oil and they were impressed with how well it did what it did. (whatever that is worth) Now, all that said... I have a friend who owns a company that builds bridges and roads. He has a lot of large, very expensive, earth moving equipment. Although he found the An-Oil-Izer an interesting test he did not, understandably, trust his equipment to an 'indicator'. He needed to know more specific information. He sent off oil samples on a regular basis for the equipment that he owned and prior to any equipment purchase. It may come down to your level of investment either in your equipment or the time and money to care for it. If my son had an An-Oil-Izer he might at least change his oil. 

Tomas, a few questions.
- What is the An-Oil-Izer made of, Wood or Black Plastic?
- Do you have operating/calibration instructions?
Sure you are not talking about Visgage made by Eitzen. Comes in a wooden box. Has two tubes each with a steel ball. One side has reference oil. Other has a plunger for sample. You pull up your oil sample into second tube. You invert tubes - watch steel balls. When steel ball in reference tube reaches designated line you look at steel ball in sample tube and read viscosity off of tube markings.
Sorry guys have been out for a few months....My research on the dielectric constant got cut short due to funding from the company I work for. Up until that point I was able to make a correlation between dielectric, moisture, temperature and viscosity. I think the issue with most dielectric testers out in the world today are that they can/do not compensate for temperature and thus viscosity. Temperature can do some very strange things to the dielectic readings of oil. When funding picks back up I will then start the correlation between dielectric and TAN, TBN, and wear particles. It is my belief that the oil condition can be scrutinized with those five properties or tests. (TBN, TAN, wear particles, visosity, and moisture content)
I was briefly reading the forums to determine why one of the dielectric instruments my lab techs are using is reporting slightly low. We use this test to analyze transformer oil. Our major clients are pg&e and smud. This test determines the breakdown of oil. Major contributing factors that would decrease a result are high moisture content and particulates such as cellulose or other fibers that hold moisture. Does someone need an analysis for fun?
I own historic vehicle both diesel and petrol.These vehicles see litle use but the oil can become contaminated by condensation in the engine.
I also have a Hoppy an-oil-izer. But how do I use it.
It contains a bottle of Red fluid a bottle of Green fluid two squezze droplet glass tubes plus two ball bearings.
I am aware of the principals involved but do not know the testing sequences and what to look for to establish a result.
Any one have the instructions

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