Ask Mobil - FAQs?

[wemorgan]

I recently came across this Mobil site with a list of customer questions and official Mobile answers.

https://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/AskMobil_Homepage.aspx

It's quite American based, but none the less there are some useful Q and As.

The question I was looking for an answer to was:

Question: Will Mixing Synthetic with Conventional Oil Cause a Gel to Form?I mixed Mobil 1 with regular motor oil. My mechanic told me I should not do this because it forms a gel; is this true? I did it on 3 Honda Accords - a 2003 with 40,000 miles, a 1990 with 201,000 miles and a 1992 with 190,000 miles.-- Jordan Mayer, Cape Coral, FL

Answer: In general, oils should be compatible with each other. It is not likely that you would form gel by mixing the two oils. However, we would not recommend mixing oils as a general practice because oils are complex mixtures of additives and base oils that can be destabilized. Lastly, why reduce the outstanding performance of Mobil 1 by adding “regular oil”. Is it economics? You would be better to run all Mobil 1 and run it longer than mixing it with “regular oil”.

 

[ched999uk]

I worked for the MoD testing oils for about 5 years. Here is my opinion: 'A regular' oil is basically a mineral based 'base' oil with the additive package poured into it. A 'Synthetic' oil is still a mineral oil but the additive package is Bonded to the base oil. What this means is that with a 'regular' oil the additive package is the lightest component and as such is burnt off (consumed) by the engine first so all you are left with is the base oil. With a Synthetic oil you just burn off a volume of the oil.
The above is a VERY simplistic explanation of the difference between regular and synthetic oils.
Semi-synthetic oil is just a regular oil with a bit of synthetic added!!!
Mixing oils these days is OK but not best thing to do as sometimes some of the additives can reduce the effects of others in the other oil.

Best advice:
Find out what the manufacturer specification for the oil is for your car. On Merc it will be something like MB 229.1, MB229.3, MB229.31, MB 229.5 or MB 229.51. Then go in to any shop that sells oil and turn the can round. Buy an oil that meets or exceeds the specification required for your car. There is no need to spend extra if the spec is no better as you would just be paying for the name not the oil. Oil companies can and do blend an oil to just pass the specification tests as the additives are the expensive part of the oil.
One thing I would say is that getting a synthetic oil that meets or exceeds the specification is a Good thing as the oil retains it properties much better.
Also do not extend oil change times!!! The oil is there to do a number of jobs including lubrication, cooling, containing deposits, cleans and inhibits corrosion. The problem with extending oil change times is that the contamination from deposits will be damaging the oil. Plus the oil gets 'chopped' up as it circulates through the engine thus gradually reducing both the viscosity and its ability to work under extreme pressure. Plus of course the filter may be blocked after an extended time and thus may be either restricted or on some cars (I hope not mercs) go into bypass mode so the oil doesnt get filtered at all!!!!!!!

 

[grober]

I recently came across this Mobil site with a list of customer questions and official Mobile answers.

https://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/AskMobil_Homepage.aspx

It's quite American based, but none the less there are some useful Q and As.

The question I was looking for an answer to was:

Question: Will Mixing Synthetic with Conventional Oil Cause a Gel to Form?I mixed Mobil 1 with regular motor oil. My mechanic told me I should not do this because it forms a gel; is this true? I did it on 3 Honda Accords - a 2003 with 40,000 miles, a 1990 with 201,000 miles and a 1992 with 190,000 miles.-- Jordan Mayer, Cape Coral, FL

Answer: In general, oils should be compatible with each other. It is not likely that you would form gel by mixing the two oils. However, we would not recommend mixing oils as a general practice because oils are complex mixtures of additives and base oils that can be destabilized. Lastly, why reduce the outstanding performance of Mobil 1 by adding “regular oil”. Is it economics? You would be better to run all Mobil 1 and run it longer than mixing it with “regular oil”.

You said the "OIL" word

 

[wemorgan]

You said the "OIL" word

I know it's like throwing a hand grenade in to a crowd. But I thought/hoped that a link with answers from Mobil themselves would be better than endless forum speculation on some matters

 

[ched999uk]

Oops sounds like I was probably best not to post that. Sorry. Please forgive a newby.

 

[Bellow]

Oops sounds like I was probably best not to post that. Sorry. Please forgive a newby.

No need to apologise. You air an always neglected point, namely how additive packages are combined with the base oil, something that synthetics are very poor at, hence semi-synthetics.
Best of all is a pure paraffinic base oil which apart from having the best properties for a lubricant also has unmatched solubility allowing absorption of a large amount of additives which will not prematurely deplete as they may in a lesser mineral oil.

 

[grober]

Oops sounds like I was probably best not to post that. Sorry. Please forgive a newby.

No worries. Just a little joke on my part.

 

[ched999uk]

That's OK. I was worried as a newby I had mentioned the unmentionable.
I am no tribologist but an electronic engineer and subsequently a web developer and marketeer. As I said I worked for MoD for 5 years in a mechanical oil test lab and did gain an insight to how the manufacturers can blend an oil to just pass a test and a few bits of info on the chemistry within the oil.
One thin that was interesting was that we had to develop an engine to be able to discriminate between synthetics as they passed the normal tests with almost a perfect score. The test we created raise the sump temp to 150degC and a hot spot 200degC. Then we could tell a very good synthetic to a poor one.
The synthetics really are soo much better, as long as they pass the car manufacturers spec.
Oh and I am a northerner who loves to speak

 

[Bellow]

ched: A couple of questions.
When did you spend your 5 years oil testing?
Did you ever evaluate an oil with a pure paraffinic base oil?
I'm curious to know if you encountered the above, or only the more prevalent mineral oil bases.

 

[ched999uk]

Started about 1992 ended about 1997/8. I only did the mechanical testing of the lubricants i.e. actually running test engines and assessing the consumption and components after test. Colleagues did the chemical tests. So unfortunately I never actually knew the chemical constituents of the candidate oils. Normally what would happen is that the MoD would put out a tender stating that they wanted say 250,000 barrels of oil to pass a certain MoD spec. Then the oil companies would provide a candidate oil for us to test and tell the MoD how much it would cost. The oil would virtually always just pass the test, we did have the odd one that failed.
At the end of the testing cycle using reference oils and candidate oils I believe the MoD would purchase the cheapest oil that passed all tests. It was rumoured that they used to end up paying about 10p a gallon!!! One thing to remember is that most of the MoD vehicles around at that time were very old generation diesels designed to operate in cool climates. When the first Gulf war started they very quickly needed an oil to enable the engines to survive the hot temperature hence our testing of synthetics and out subsequent creation of a synthetic oil test for MoD.

I can go on cant I

I can probably find out about Pure Paraffinic base oils as I am still in contact with some of the chemists who may remember. The mechanical oil testing lab has no long gone as they now 'trust' the manufacturers of the oils to test it themselves!!!

 

[Bellow]

Thanks ched. No need to ask about PP as I can deduce from what you have already posted that the chances of the company I know of who market PP oils wouldn't enter into an arrangement such as you have described it! 10p a gallon! They would sooner drink it than sell it at that price!

 

[Bellow]

Ched, a few more questions for you if you chance upon this.
The high temp test - what particular measurable parameters of the oil were monitored? For what reason(s) did an oil most commonly fail the synthetic test?
And was the engine condition after test assessed, ran to failure, etc?

Thanks in advance.