Confirm PN for 2020 3.5EB Spark Plugs and Diff/TCase Oil

[kmc0929]

Anyone help confirm the MC part number for Spark Plugs on the 2020 Exp Ecoboost? I keep seeing several PNs show as applicable...

Also planning to vacuum extract the old fluids out of the diffs and t-case. any one know the correct MC lubricant, thought on quantity to do both diffs and the t-case?

 

[TheDoug]

I am not sure about spark plugs part number as I have gone with a colder plug since I am tuned.

There are drain bolts on rear diff and transfer case. The only one you have to suck out it front diff. Really easy to do.

 

[bb37]

Ford Parts says SP594 (CYFS12YRT3) for a 2020.

Starting 1/18/2022, the plug changed to SP596 (DYFS12YPT).

Ford Tech Makuloco talks about this. Note that the older plug has a taper seat while the newer plug has a copper gasket. Also, he says that the newer plugs are indexed which means that the machining of the threads combined with the gasket combined with the specified tightening torque positions the ground electrode in the combustion chamber where the engineers want it to be. https://youtu.be/zU4WbXciv1k?si=72ITs6jmMuymPcxk

 

[BSarchet]

I asked this question on another thread but I don’t think anyone saw it. Do people here think that the plugs need to be indexed? I bought the ones that @LokiWolf recommends and installed them a couple of weeks ago. But they didn’t have the crush washers like the ones I took out and mine is a ‘22. My car seems to be running fine but just curious about opinions on indexed plugs.

 

[bb37]

You can't mix taper seat plugs with plugs that use a gasket. The spark plug holes in the cylinder head are machined differently.

Is indexing important? That's debatable. Indexing plugs is an old engine builder's trick to maximize flame propagation and burn rate in the cylinder. Does it matter given the tuning and analysis that's been done in the Ecoboost combustion chamber? I can only assume that Ford's engine guys found some improvement in power and/or efficiency by indexing the plugs. Changing head machining and adding a different spark plug SKU is kind of a big deal when you are making thousands of engines.

 

[LokiWolf]

I asked this question on another thread but I don’t think anyone saw it. Do people here think that the plugs need to be indexed? I bought the ones that @LokiWolf recommends and installed them a couple of weeks ago. But they didn’t have the crush washers like the ones I took out and mine is a ‘22. My car seems to be running fine but just curious about opinions on indexed plugs.

Those plugs will work in both places, as long as you followed Torque specs. Many 3rd party people that know WAY more than me about performance on these Ecoboosts say the indexing makes no difference. There are several that have documented that the factory installed ones aren't always indexed from the factory. It just isn't a thing. Install to the proper torque specs and you will be good.

 

[LokiWolf]

You can't mix taper seat plugs with plugs that use a gasket. The spark plug holes in the cylinder head are machined differently.

Is indexing important? That's debatable. Indexing plugs is an old engine builder's trick to maximize flame propagation and burn rate in the cylinder. Does it matter given the tuning and analysis that's been done in the Ecoboost combustion chamber? I can only assume that Ford's engine guys found some improvement in power and/or efficiency by indexing the plugs. Changing head machining and adding a different spark plug SKU is kind of a big deal when you are making thousands of engines.

The new Motors still have the tapered seat.

Ford has changed the plug part number in the 3.5 several times through the years, and it was NEVER about performance or engine longevity, and always about saving a buck, or a penny. Ford has NGK make a plug that barely meets the requirement these motors need. That has been proven time and time again. The fact they have lowered the replacement interval, and even then people replace them sooner, and see improvements in power, idle, and MPG almost immediately.

 

[Yupster Dog]

Ford has NGK make a plug that barely meets the requirement these motors need. That has been proven time and time again.

Dollar

 

[BSarchet]

Those plugs will work in both places, as long as you followed Torque specs. Many 3rd party people that know WAY more than me about performance on these Ecoboosts say the indexing makes no difference. There are several that have documented that the factory installed ones aren't always indexed from the factory. It just isn't a thing. Install to the proper torque specs and you will be good.

I torqued them to 12 ft / lbs per the specs I saw. Which speaking of that, there is no way that’s what they were torqued from the factory because I had a helluva time getting some of those out of there, particularly the two in the back.

I appreciate the quick response, thank you!

 

[LokiWolf]

I torqued them to 12 ft / lbs per the specs I saw. Which speaking of that, there is no way that’s what they were torqued from the factory because I had a helluva time getting some of those out of there, particularly the two in the back.

I appreciate the quick response, thank you!

They ALWAYS take way more to remove them, because they seize. YET another reason to change them more often!

 

[Boosted]

You asked a few questions:
Spark plugs: I am planning to use the NGK Ruthenium plugs when I change mine in the spring.

Transfer case uses Mercon LV. From Rock Auto its ~$6 per quart and you need ~2 quarts.

Differentials take 75W-85 which is little odd. The Motorcraft fluid is expensive (~$22/quart) and you need to add the friction modifier if you have limited slip rear differential. For that price you can get Amsoil or go slightly off-grade locally you can find many options for 75W-90 which wouldn't cause any issues at all. Just be mindful if you have limited slip you may need to add a friction modifier if the fluid doesn't include it. Some fluids already have it in their additive package which makes it easier. You probably need about 5 quarts to do front and rear differentials. If you want to make changing the rear differential fluid easier in the future get a gasket from LubeLocker so that you can reuse it.

The front differentials are packed in too tight to take the cover off reasonably so just use a pump or oil extractor to pull as much fluid as possible and refill. The same fluid as the rear.