Help about 5w-20, 5w-30, 5w-40 and 5w-50 oil

[MRASPHALTO1]

My third-generation Coyote, which I bought a few months ago with 129,000 miles at auction, is making some strange noises (see this post where you'll find a video of the sound: https://www.mustang6g.com/forums/threads/loud-noise-from-engine-coyote-gen3.228893/). Some mechanics have told me to increase the oil viscosity (when I got the car, I put in Mobil 1 5W-20 because that's what the cap said).

After considering what several people told me, I'm thinking of using Molygen 5W-30, but I recently spoke with someone who works at a race car shop, and he told me that these engines usually use 5W-40 or 5W-50 viscosity oils.

This seemed a bit crazy to me since it's too viscous for this engine, but since I don't have experience with fluids and physics, I'd like to know what oils you usually use in your Mustangs.

Do you recommend 5W-30, 40, or 50 oils?

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[LCK22GT]

5w-30 per Ford spec for my 22 Gen 3. If a mechanic told me to use 40 or 50 for regular street use, I’d find another mechanic.

 

[WItoTX]

5W-50 is normal for street use, 15W-50 is what I use but I'm only on track.

GM recommends 15W-50 for track, 0W-40 for street use in the ZLE and SS 1LE.

 

[sk47]

Hello; After reading posts the last few years my take is many have switched to 5-w-30. if memory serves I think Ford may have changed to 5-w-30 on later models.
That said you are out of warranty so can us any oil you are comfortable with, but i get such is not your concern. I do not recall reading of owners using 40 or 50 weight oils.

There are many threads about coyote engine noises perhaps someone familiar with those noises can tell you if your noise is one of the more common sorts. Do a search on here for an oil additive called creatine, I think. Some members recommend that additive to help with a common noise.

 

[MRASPHALTO1]

5w-30 per Ford spec for my 22 Gen 3. If a mechanic told me to use 40 or 50 for regular street use, I’d find another mechanic.

trust me, my reaction was similar, but I understand that since he's a race car mechanic, maybe he gave me that answer thinking that I used my Mustang for drag racing or on the track when I really only use it daily and occasionally floor it.

 

[sk47]

Hello; I listened to the sound recording. If it was a V8 with pushrods I would think it is a valve train noise. Maybe such as a hydraulic lifter not pumping up properly. I had such a similar noise on my second car back in 1966. I replaced a lifter and the noise went away.
The Coyote uses overhead cams however, but I figure have some version of a hydraulic lifter.
An engine can run a long time with such.

Another thing to consider may be piston slap. A question; is the noise louder at startup when cold and then gets quieter as the engine warms up??? Piston slap is not a fatal problem but also not fun to live with.

The sound did not make me think of a rod knock, but a clue can be had when driving. Does the noise get louder say when you lift off the gas?

Good luck and keep in mind these are guesses.

 

[MRASPHALTO1]

Hello; I listened to the sound recording. If it was a V8 with pushrods I would think it is a valve train noise. Maybe such as a hydraulic lifter not pumping up properly. I had such a similar noise on my second car back in 1966. I replaced a lifter and the noise went away.
The Coyote uses overhead cams however, but I figure have some version of a hydraulic lifter.
An engine can run a long time with such.

Another thing to consider may be piston slap. A question; is the noise louder at startup when cold and then gets quieter as the engine warms up??? Piston slap is not a fatal problem but also not fun to live with.

The sound did not make me think of a rod knock, but a clue can be had when driving. Does the noise get louder say when you lift off the gas?

Good luck and keep in mind these are guesses.

It's noisier when it's cold; it's quieter when it warms up. I've noticed that if I use an octane booster, it quiets down a bit.

When I accelerate, the noise tends to decrease, although I think that's because the engine's main sound masks the strange noise. I've even wondered if it might be a tappet that isn't getting enough oil, perhaps it's worn, or maybe there's some other wear on a camshaft.

 

[GregO]

It's noisier when it's cold; it's quieter when it warms up. I've noticed that if I use an octane booster, it quiets down a bit.

When I accelerate, the noise tends to decrease, although I think that's because the engine's main sound masks the strange noise. I've even wondered if it might be a tappet that isn't getting enough oil, perhaps it's worn, or maybe there's some other wear on a camshaft.

GDFI noise possibly.
Oil; 5W-40 or 0W-40
Brand; Anything that is local retail and in stock, Castrol Euro or Mobil Euro.
Coyotes are DOHC bearingless cam journals so cold oil pumpability is critical, with that only use 0W or 5W…. 40wt gets you a robust additive package that 30wt or lower doesn’t have by current API standards.
Save yourself the headache and expense of boutique oils.

 

[MRASPHALTO1]

GDFI noise possibly.
Oil; 5W-40 or 0W-40
Brand; Anything that is local retail and in stock, Castrol Euro or Mobil Euro.
Coyotes are DOHC bearingless cam journals so cold oil pumpability is critical with that only use 0W or 5W…. the 40wt gets you a robust additive package that 30wt or lower doesn’t have by current API standards.
Save yourself the headache and expense of boutique oils.

i'm from Dominican Republic

So it's very unlikely the temperature will reach -2°C. I think the lowest temperature my city has ever had is 20°C or 10°C, exaggerating a bit. I understand that the #W refers to how well the oil performs in cold weather.

In a tropical country, do you think I could use 0W-30 or 0W-40 and the engine wouldn't have any problems?

 

[GregO]

i'm from Dominican Republic

So it's very unlikely the temperature will reach -2°C. I think the lowest temperature my city has ever had is 20°C or 10°C, exaggerating a bit. I understand that the #W refers to how well the oil performs in cold weather.

In a tropical country, do you think I could use 0W-30 or 0W-40 and the engine wouldn't have any problems?

I’d run 0W in Dubai if I lived there.
0W-xx oils are built on a better base oil than 5W’s
The lower W number is really about getting start up oil to the cam journals as quickly as possible, as mentioned there are no bearings supporting the cams, only aluminum.

 

[sk47]

It's noisier when it's cold; it's quieter when it warms up

Hello; Please keep in mind this is a WAG (wild a## guess) as I am not hearing in person. Even if I were present could not 100% say for sure. My guess at this point is piston slap.

V8 engines are built with the crankshaft in the center & low in the block. The cylinders are set at an angle off the crankshaft. Often a 90-degree angle from each cylinder. Not sure if your engine is 90 degrees but the actual angle is not critical.
Because of the angle the pistons do not go straight up and down relative to the crankshaft. The connecting rod pushes a piston at a 45 degree angle in a 90 degree block. This has a tendency to put a bit of side load on the piston. Since the piston has to be free to rotate on the connecting rod that means the piston can "slap" the outside wall of the cylinder on a compression or exhaust stroke.
Most engines have very little piston slap or at least not loud enough to hear. Some are known for such. Late 1990's and early 2000's GM V8's were bad for it. My neighbor had one I could hear from around 50 feet away on clod startup. Then as the parts got hot and the tolerances closed up the slap quieted down.
When i bought my pickup I went for the 4.8 V8 rather than the 5.3. Same block but the 4.8 is a shorter stroke. No loud startup slap so far.

The Coyote has oil squirters which send a jet of oil into the cylinders from the bottom & under the pistons. Not sure if this feature ought to help or not.

If it does turn out to be piston slap an engine can live a long time with it being more of an annoyance than a fatal thing. An exception may apply on some Coyote engines with the spray in plasma cylinder linings. Those linings are super thin. They are hard so will resist wear I suspect.
Some pistons have special coatings on the skirt of the piston in part to deal with such a thing as piston slap. If your piston had such a lining it may have worn off in over 120K miles. I am not familiar with additives for this. Maybe Creatine?? Maybe Z-MAX ??. Maybe a thicker weight oil?

If you do your own oil change catch the oil in a clean container. Look for metal glitter & hopefully find none.
Good luck

 

[Hifiguy]

5w-30 per Ford spec for my 22 Gen 3. If a mechanic told me to use 40 or 50 for regular street use, I’d find another mechanic.

HTHS is what matters. Consider why ford engineers picked 5w30, and you’ll become a thiccy

5w50 will always provide more of a safety margin than 5w30, but you have to replace it more often.

5w30 will also give you significantly more horsepower and better emissions, while also giving you 10-20 degree cooler oil temps. It’s a good compromise while having a decent margin of safety before metal on metal wear occurs. It’s why Ford specs it even though it’s not the “safest” for your engine

 

[robvas]

5w30 will also give you significantly more horsepower and better emissions, while also giving you 10-20 degree cooler oil temps.

 

[Hifiguy]

youtube.com/watch?v=zLBgIve1YzY

20hp difference in this case
Probably not be as big of a gap between 5w30-5w50

 

[falcongtho3]

Use what the cap says. If there is an issue, change brands. My 03 Mach 1 4.6 32V absolutely hates Mobil 1 but thrives on Castrol Edge. Ford does say that 5W30 is recommended for track use, for street use, 5W20. GT350s, Boss 302s, HioPos and Ford GT get a 5W50 recommendation, but have you seen it come out of the bottle or the oil pan? Like water. Not even thick water.

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