Got an E-Mail from a very trusted friend, who has owned exotics. He's been an engineer and machine designer since 1978. PS he still owns his first car. 1972 superbeatle, that he bought when he was 17!! It still runs great, so he's not into disinformation. I can imagine some of the Amsoil Royal Purple, never use anything but designer name brand toilet paper crowd may try to flame this.... But here is the complete E-mail chain.
For all you gearheads (Don, etal). Here is some info from the tech guy at the Shell refinery I used to work at. It refers to alternating between synthetic oil brands for automobile oil changes, and has some other good information.
Dave
Subject: Mixing of Auto Engine Oil
You may find this interesting……..
I tracked down this Shell chap (Matt) – he is the Shell Tech Rep in the lubricants business – to try and settle this urban legend thing about not mixing oils.
That was after the JiffyLube guy told me when I got my oil changed (from the free Shell Oil/Lube change) that you could not switch synthetic oil brands. I’m sure he was just repeating what the Big Oil salesmen told him.
Matt is about a 20 yr Shell employee - his response is documented below …….
No issues with mixing brands or types of motor oil.
So I continue to be NOT WORRIED about switching the oil brands around as I do.
Terry
Subject: Mixing of Auto Engine Oil
Here’s the info that I got from Matt last week to my questions below. It was a very informative conversation for me – Matt is quite knowledgeable in the lubrication area ! I’m sure he’ll correct me if I have mistranslated.
Attached is Pennzoil document with further anti-wear additive info (we can share it with the world).
With one possible exception, Matt has no issues (and has never seen a problem) with mixing different brands of the same oil (i.e. Mobil 1 with Pennzoil Synthetic) or different types of oil (full synthetic with full mineral) or different brands and different types (Royal Purple synthetic with Shell X-100 mineral) with the premise that the engine is in good condition in the first place. In other words, he has seen no compatibility issues. No problems would be expected if you switched from mineral to synthetic at alternating oil changes.
The possible exception is “cleanout” of an old engine. If you put high quality modern day synthetic oil into an old engine (even in good shape) that has been using mineral oil for a long period, the risk is that the superior cleaning power in the synthetic will wash out accumulated dirt in the old engine. An example - If the piston rings have been using mineral oil and built up dirt “over the years” and you switch to Pennzoil synthetic you may see all of the “old” dirt cleaned out and may see some ring bypassing.
Other facts, food for thought and recommendations:
Additive packages in engine oils change every couple of years with API grades. True for Shell. True for other brands. So compatibility changes are present even if you stick with the same type and brand.
Mineral oils swell seals (a good thing) for a better seal (no oil leaks) ! Synthetic oils do not – additives are now included to promote that characteristic.
Synthetic Oils clean better than the std Mineral Oils (based on engine testing).
Watch out for and do not use aftermarket Additives in your oil because:
o Possible compatibility issues – do not know how they will react. These small volume suppliers could not possibly test their products against all of the oils (especially the additive packages contained within) on the market today.
o You do not need them with today’s modern oils.
Older engines need more anti-wear additives. For flat tappet camshafts. See the attached paper from Pennzoil.
For the older engines, Matt usually recommend using the Shell Rotella T Triple Protection 15W40, the Rotella T5 10W40 (synth blend) or the Rotella T6 5W40 (100% synthetic). All of them have the higher anti-wear additive levels needed for flat tappet camshaft engines.
“High Mileage” Oils (as marked on the package) usually contain more anti-wear additive and seal swell.
I think I covered it all. Thanks again to Matt for taking some time to discuss this.
Terry
Subject: Mixing of Auto Engine Oil
Greetings Mathieu,
I got your name from the Rotating Equipment group here in the Refinery.
I have a consumer question on engine oil that I hope you can help me with. Alternatively perhaps you could refer me to the appropriate Shell Tech person to do so.
The question is about the risks (or no risks) of using various brands of engine oil. I just got my “free” oil change and lube at the local Jiffylube – part of the promotion for the “new” Pennzoil synthetic. And got some interesting info from the Jiffylube guys in the shop in this regard.
More specifically (all viscosities are 5W-30 in following cases):
1. Are there any issues with switching oil brands at each oil change (but stick to the same type of oil) ? I’m not talking about mixing up Oil brands in the same oil change …. I’m referring to using for my first oil change 100% Mobil-1 Synthetic, the next oil change being 100% Pennzoil synthetic, then trying Quaker State Synthetic, then Autozone Synthetic, then back to Mobil-1 synthetic, etc ? My truck seems to be on a regular diet of Pennzoil &/or Mobil-1 synthetic oil changes.
a. Does the answer change if I’m only changing between Shell Products – say Pennzoil synthetic and Quaker State synthetic ?
2. Are there any issues with switching oil brands and oil types at each oil change ? I’m not talking about mixing up Oil in the same oil change … I’m referring to using for my first oil change 100% GM semi synthetic, the next oil change being 100% Mobil-1 fully synthetic, then back to semi synthetic, then to Pennzoil fully synthetic, etc. My car seems to be on an alternate diet of GM semi synthetic oil and then a change of fully synthetic oil.
3. What about throwing in a “conventional” oil change in occasionally with any of the above ?
My automobile Owner’s Manual (Automobile manufacturers position) for the oil changes tells me to use oil with minimum specs of blah, blah, blah. There is no recommendation for a specific brand of motor oil or no warnings if I mix brands. Although my one car has “Mobil-1” stenciled on the fill cap.
Is there a Shell technical position for the above cases ? And the reasoning.
I know the Shell commercial position will be use Pennzoil, use Pennzoil, use Pennzoil ………….
For all you gearheads (Don, etal). Here is some info from the tech guy at the Shell refinery I used to work at. It refers to alternating between synthetic oil brands for automobile oil changes, and has some other good information.
Dave
Subject: Mixing of Auto Engine Oil
You may find this interesting……..
I tracked down this Shell chap (Matt) – he is the Shell Tech Rep in the lubricants business – to try and settle this urban legend thing about not mixing oils.
That was after the JiffyLube guy told me when I got my oil changed (from the free Shell Oil/Lube change) that you could not switch synthetic oil brands. I’m sure he was just repeating what the Big Oil salesmen told him.
Matt is about a 20 yr Shell employee - his response is documented below …….
No issues with mixing brands or types of motor oil.
So I continue to be NOT WORRIED about switching the oil brands around as I do.
Terry
Subject: Mixing of Auto Engine Oil
Here’s the info that I got from Matt last week to my questions below. It was a very informative conversation for me – Matt is quite knowledgeable in the lubrication area ! I’m sure he’ll correct me if I have mistranslated.
Attached is Pennzoil document with further anti-wear additive info (we can share it with the world).
With one possible exception, Matt has no issues (and has never seen a problem) with mixing different brands of the same oil (i.e. Mobil 1 with Pennzoil Synthetic) or different types of oil (full synthetic with full mineral) or different brands and different types (Royal Purple synthetic with Shell X-100 mineral) with the premise that the engine is in good condition in the first place. In other words, he has seen no compatibility issues. No problems would be expected if you switched from mineral to synthetic at alternating oil changes.
The possible exception is “cleanout” of an old engine. If you put high quality modern day synthetic oil into an old engine (even in good shape) that has been using mineral oil for a long period, the risk is that the superior cleaning power in the synthetic will wash out accumulated dirt in the old engine. An example - If the piston rings have been using mineral oil and built up dirt “over the years” and you switch to Pennzoil synthetic you may see all of the “old” dirt cleaned out and may see some ring bypassing.
Other facts, food for thought and recommendations:
Additive packages in engine oils change every couple of years with API grades. True for Shell. True for other brands. So compatibility changes are present even if you stick with the same type and brand.
Mineral oils swell seals (a good thing) for a better seal (no oil leaks) ! Synthetic oils do not – additives are now included to promote that characteristic.
Synthetic Oils clean better than the std Mineral Oils (based on engine testing).
Watch out for and do not use aftermarket Additives in your oil because:
o Possible compatibility issues – do not know how they will react. These small volume suppliers could not possibly test their products against all of the oils (especially the additive packages contained within) on the market today.
o You do not need them with today’s modern oils.
Older engines need more anti-wear additives. For flat tappet camshafts. See the attached paper from Pennzoil.
For the older engines, Matt usually recommend using the Shell Rotella T Triple Protection 15W40, the Rotella T5 10W40 (synth blend) or the Rotella T6 5W40 (100% synthetic). All of them have the higher anti-wear additive levels needed for flat tappet camshaft engines.
“High Mileage” Oils (as marked on the package) usually contain more anti-wear additive and seal swell.
I think I covered it all. Thanks again to Matt for taking some time to discuss this.
Terry
Subject: Mixing of Auto Engine Oil
Greetings Mathieu,
I got your name from the Rotating Equipment group here in the Refinery.
I have a consumer question on engine oil that I hope you can help me with. Alternatively perhaps you could refer me to the appropriate Shell Tech person to do so.
The question is about the risks (or no risks) of using various brands of engine oil. I just got my “free” oil change and lube at the local Jiffylube – part of the promotion for the “new” Pennzoil synthetic. And got some interesting info from the Jiffylube guys in the shop in this regard.
More specifically (all viscosities are 5W-30 in following cases):
1. Are there any issues with switching oil brands at each oil change (but stick to the same type of oil) ? I’m not talking about mixing up Oil brands in the same oil change …. I’m referring to using for my first oil change 100% Mobil-1 Synthetic, the next oil change being 100% Pennzoil synthetic, then trying Quaker State Synthetic, then Autozone Synthetic, then back to Mobil-1 synthetic, etc ? My truck seems to be on a regular diet of Pennzoil &/or Mobil-1 synthetic oil changes.
a. Does the answer change if I’m only changing between Shell Products – say Pennzoil synthetic and Quaker State synthetic ?
2. Are there any issues with switching oil brands and oil types at each oil change ? I’m not talking about mixing up Oil in the same oil change … I’m referring to using for my first oil change 100% GM semi synthetic, the next oil change being 100% Mobil-1 fully synthetic, then back to semi synthetic, then to Pennzoil fully synthetic, etc. My car seems to be on an alternate diet of GM semi synthetic oil and then a change of fully synthetic oil.
3. What about throwing in a “conventional” oil change in occasionally with any of the above ?
My automobile Owner’s Manual (Automobile manufacturers position) for the oil changes tells me to use oil with minimum specs of blah, blah, blah. There is no recommendation for a specific brand of motor oil or no warnings if I mix brands. Although my one car has “Mobil-1” stenciled on the fill cap.
Is there a Shell technical position for the above cases ? And the reasoning.
I know the Shell commercial position will be use Pennzoil, use Pennzoil, use Pennzoil ………….
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