Moly vs no Moly - Engine break in?

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May 13, 2011
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Location
Virginia
Getting a new engine in my 2018 CX-9 (2.5 Skyactiv Turbocharged engine) with 65K miles on the clock. Dealer says it should be back in my hands at the end of January... After two months of waiting.

I'm a weird situation where I'm breaking in a factory new engine but I'm out of warranty and doing my own work.
(Before 60K, I had been taking it to the dealership and having them use their oil and filters.)

Mazda Dealership oil is Idemitsu, which I've seen VOAs have high levels of Molybdenum.
Owner's manual recommends Castrol, which I normally use in my other vehicles. VOAs I've seen show very low levels of Molybdenum.

What's the general consensus on having Moly in a new engine for the break in period?
 
Do "engine break in oils" have high moly I wonder? I think I've seen Redline and Amsoil versions of break in oils.
 
Break-in oils are typically light on friction modifiers. I use Driven BR for break-in which contains no moly, nor much of anything else besides a load of ZDDP. Let the anti-wear additives do their thing, establish their tribofilms, and get everything else out of the way.

VOA of Driven BR30

Aluminum
Chromium
Iron
Copper
Lead
Tin
Molybdenum
Nickel
Manganese
Silver
Titanium
Potassium
Boron
Silicon
Sodium
Calcium------------649
Magnesium
Phosphorus--------2588
Zinc----------------2832

KV100--------------11.8
TBN-----------------3.1


Obviously not meant for a normal OCI. It's done at 500 miles.

That said, your engine likely doesn't need this. If they are warrantying the engine, you might prefer to do what they say. If it was me and my engine, I'd run BR30 in it for 250-500 miles with varying rpm/load and frequent heat cycling. I tend to overkill things at times though, like breaking in an engine like I'm about to race a full cup series season with it. I'd rather do too much than not enough.
 
Break-in oils are typically light on friction modifiers. I use Driven BR for break-in which contains no moly, nor much of anything else besides a load of ZDDP. Let the anti-wear additives do their thing, establish their tribofilms, and get everything else out of the way.
Hmm, I thought break-in oils were typically high moly. This particular one may be the outlier.
 
Hmm, I thought break-in oils were typically high moly. This particular one may be the outlier.

No. A big part of "break-in" is establishing anti-wear tribofilms quickly, namely ZDDP surface reactions with iron. Friction reducers like MoDTC don't have a role here, and can actually hinder ZDDP reactivity in this regard. You don't want anything competing with your primary anti-wear additive for surface area during break-in.

I think people think break-in oils have high moly because they see TGMO with high moly, but that's not a break-in oil. It's just their initial fill, possibly using MoDTC for its anti-oxidant benefits in preventing LSPI or could be just to be generous. Who knows. Either way, their engines are likely put through a "dry" break-in after assembly and considered "broken in" for the most part from the time you buy it. This is likely the case with the OP's engine as well.

OEMs typically don't require a break-in period for their engines, saying their good to go with whatever recommended oil, but the same OEMs also say a quart of oil consumption every 1,500 miles is "normal" so I kinda take such as that with a grain of salt.

Maxima Break-In 10W-30
Mo - 0
Ca - 592
P - 3681
Zn - 3731

Motul Break-In 10W-40
Mo - 0
Ca - 9
Mg - 992
P - 2343
Zn - 2492

Amsoil Break-In SAE 30
Mo - 0
Ca - 266
P - 2340
Zn - 2716

Lucas Break-In SAE 30
Mo - 0
Ca - 1735
P - 4466
Zn - 4809
 
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Aren't assembly lubes very high in moly?

In the case of assembly grease, the moly is used for its anti-oxidant and anti-corrosion benefit. It's also usually in the form of MoS2 and can provide some slickness to parts that may get turned over by hand a few times during assembly. There's no heat to drive ZDDP reactivity during assembly, especially on non-ferrous surfaces like the bearings, so moly-EP based grease fills that role.
 
Honda used to be pretty insistent that the factory fill, which incorporated lots of molybdenum from assembly lubes, be kept in the engine for the full initial OCI.

As I understand it, the logic was the molybdenum kept high temperature spots from forming on cylinder walls during break in. These spots in turn could result in oil coking and compromise ring sealing. So the high-molybdenum path makes sense to me, but if it’s important to Mazda that should be what’s in the engine as installed. As long as you run that for a reasonable interval I don’t think what comes after is important.
 
It will not matter. study up on what occurs with the engine breaking in. There are zero passenger car engine oil oils that can prevent the break in wear.
 
I assume that these engines are shipped with no oil inside so the dealer will be adding the oil before startup. Ask them what is in there.
 
honda and toyota
 
Why the new engine?
I would not do what you did the last time.
Are you sure I didnt drive that car at least once?

Run a nice 'conventional' oil and maybe a 1/4 bottle of Lunati break in additive and reserve the rest for top up.
That japanese engine should have moly coated pads on the piston skirts and I assume it has a finger follower roller cam DOHC.
Regardless, DOHC have very light valvespring over the nose pressure due to the tiny valves being managed.
So you are just managing wear-in of bearing-less cam bores, oil pump and piston side loading - which is best managed with ZDDP.
This gets used up so I would just add a bit of break in elixer after time when the engine gets to be thrashy.

 
Why the new engine?
What happened to the dealer maintained engine @ 65k miles?

Cracked Cylinder Head due to a casting defect. Hence why they're replacing it under warranty.
Common problem on the 2016-2019 Skyactiv Turbos for some reason; they crack around the bosses where the exhaust manifold bolts to the head and leak coolant.

They're replacing the entire engine block to save on labor costs. Judging by the parts list that was provided to me, there's a revised exhaust manifold gasket among other changes to the cylinder head made between the 2016-2018 and 2019+ engines.
 
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