Will 5w30 Full Synthetic Prevent Proper Break-In?

[Albertcado]

I just got my car back with a new short block under warranty from the dealership,
but the tech put 5w30 Full Synthetic in the new engine because I simply asked if that is something Ford would approve. Basically throughout the warranty process I asked him about it and without a heads up or asking (he didn't ask Ford either if that was okay for the new engine) he just went ahead and used 5w30 FS and I ate the cost of the oil. He assures me it will still break in properly and I won't have to worry about the rings not seating properly since the difference in factory oil and the 5w30 FS is not huge. I was planning on switching over to 5w30 Full Synth on my 1st oil change on the new engine anyways, but obviously propery break-in is the biggest concern.

Do you guys think it will be okay or is this a huge concern? The tech (who is very competent, he is the only one who works on engines at my reputable dealership and has a lot of experience with mustang engine work, short block, long block replacement, etc.) tells me to drive it easy for the 1st 500-1000 miles and get an oil change in 5000. Should I go back and have them do the oil change now to 5w20 blend while it has very low miles on it to be safe or will the car still be able to break-in properly on the 5w30 Full Synth?

*side note, 1st engine was broken in properly with the factory oil (5w20 blend) and 1st oil change was done around 3k miles. This engine eventually had bad enough scoring to cause oil consumption and oil burning in cylinders, which Ford immediately approved for this 2nd short block so...

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[Deleted member 35644]

Plenty of cars, including some very high-end luxury cars come from the factory filled with Mobil1. You will be fine.

 

[GregO]

@Albertcado
https://www.mullenixracingengines.com/how-to-break-in-your-engine

Read this link and discuss this with your Ford Motor Tech.
Don’t jeopardize your new short block warranty.
I’d suggest a candid conversation with the Dealer on Fords guidelines for the VooDoo 5.2 break-in procedure as that and your Gen3 use coated cylinders and Ford has a supplemental procedure for proper ring break-in.
Yes the VooDoo uses lower tension rings vs. the Gen3 but there is merit to an oil being too good and wrecking the burnishing process.

 

[Cory S]

Drive it hard. Rings will break in fine.

 

[Jackson1320]

Don’t drive it easy that’s the last thing you want to do. You need cylinder pressure to seat the rings. Drive it just like you plan to drive it and add in some hard pulls 0-100. Your competent mechanic doesn’t sound so competent

 

[Rapid Red]

NO

 

[Albertcado]

In many engines, the rings are going to be seated or have their opportunity to be seated very early on, like in the first few hundred miles. Depending on the application, sometimes less than that.

As other have pointed out, putting the engine under moderate loads, accelerating and decelerating (engine breaking) will press the rings into the cylinder walls and lead to seating of the rings. The rest of the assemblies will seat over time.

Avoid excessive idling. Avoid freeway/highway traffic where you are always driving under the same speed/load/temps. I wouldn't baby the engine.

Southern California? Hills or canyons nearby? Bring the engine and the car up to temps and head for the hills.

Several great comments, posts and articles regarding engine break-in within this forum. Read-up on those and enjoy yourself.

Regarding the type of oil to put in, I'd use the oil and filter for the engine as recommended by Ford for two reasons: 1) the Engineers who designed the engine specified it, and 2) this will protect you against any future warranty issues. If the engine is modified in some way later, the type and weight of oil may need to change.

Would you still stay away from taking it into the higher rpms early on?
So far I haven't taken it above 4k rpm

 

[GregO]

Would you still stay away from taking it into the higher rpms early on?
So far I haven't taken it above 4k rpm

The motor is designed to tach out over 7500 rpms. Don't bounce it off the rev limiters and take it up to 6000 to 7000 and back down using compression braking to pull oil into the ring area to flush out the burnishing particles.

 

[WildHorse]

That thinking was from the cast iron ring era.

 

[dbtgt]

Plenty of cars, including some very high-end luxury cars come from the factory filled with Mobil1. You will be fine.

The 20-22 Shelby GT500 comes filled with Motorcraft 5W/50 (XO5W50 QGT) Full Synthetic from the factory.
Obviously Ford thinks it will break in properly with full synthetic...

 

[Rapid Red]

That thinking was from the cast iron ring era.

You're correct my friend.

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