Quieting a noisy Subaru EJ25 engine...

[Lex94]

After long experimentation with a Subaru EJ25 chatter box, I am done (I am not kidding...this time) and have found Oil Ambrosia.

3 parts Pennzoil Conventional YB 10w30
1 part Mobil Super 5000 5w20

This combination has quieted much of the cold-start clatter and has a silky turbine-smooth hot operation. I may do a UOA to see if this empiricism holds up to physical reality.

If you have an engine with Noise, Vibration, and Harshness issues...Give this combination a try and see what you think.

 

[Lex94]

Messed that one up...Admins...Make "Edit" time longer!

Should be:

4 parts Pennzoil Conventional YB 10w30
1 part Mobil Super 5000 5w20

 

[Subdued]

I thoroughly enjoy the sound of the EJ25, right down to the perpetual piston slap. No thanks!

 

[Lubener]

Amazing case of mind over matter.

 

[Lex94]

Originally Posted By: Subdued
I thoroughly enjoy the sound of the EJ25, right down to the perpetual piston slap. No thanks!


Ohhh, you're one of..."Those". LOL!

The owner of this nasty little beast will be back next week to take this thing away. Warning to others: If you leave a car with me for an extended period of time, I will experiment on it! My M272 Mercedes is whisper quiet so I find these EJ25 engines just scary.

 

[salv]

Ha! It is amazing what a little MS5K can do.

 

[CourierDriver]

old Subaru engines always sounded like an old vw aircooled engine to me, someone told me a subaru older model engines were a vw design with water jackets,,i dunno.

 

[Lex94]

It does make sense...Here is a Subaru EA52

http://www.porcupine73.com/pics/engine/Subaru-EA52-1.jpg

These engines sound awful but run forever.

 

[Lex94]

Originally Posted By: salv
Ha! It is amazing what a little MS5K can do.

Yup...Mobil Super 5000 10w30 alone was a bit noiser than PYB when hot but diminished cold start chatter significantly. Adding just a bit of MS5K 5w20 to the mix helped quell a lot of cold start noise. I tried a 50:50 mix but the hot operation had too much NVH...a 1:4 mix with 5w20 was optimal. The Mobil sodium additives work good at cold start and not too bad when hot.

I switched out Mobil 1 for the 4:1 mix on all my power equipment. All run more smoothly now.

 

[Rob_Roy]

How many miles are on this "noisy" engine? The 2.5 in my 2012 Legacy is very quiet.

 

[ARCOgraphite]

We ran Rotella triple 10w30 and the final qt of Shell Formula 5w30 in our EJ with good results. When We ran oci with MC5K 5w30 I sub'd 1 qt with MC5K 10w40 in the summer. No Fuel mileage hit always over 30 mpg ave in the summer with a 5 gear stick and the economical/powerful Jekyll/Hyde personality VTEC valve control on this engine in an '09 forester (EJ253)

Isnt the new Mobil super a sodium package?

 

[Lex94]

Ya know...I was going to try Rotella 10w30 until I stumbled on the PYB 10w30...Ahhhh, OK...Once more with the Rotella 10w30.

PYB 10w30 (I tried the PYB 5w20 and 5w30 but they were not as good) was the only oil that totally stopped the vibration thru the gas pedal and steering wheel...and fuel mileage went up noticeably.

Mobil Super 5000 uses sodium package. I would probably sacrifice the extra "smooth and quiet" PYB and use MS5K in a newer engine for the low ash/low SAPS to control engine deposits and protect the cats.

 

[05LGTLtd]

Pour ~5oz of MMO in the fuel tank before your next fill up if you really want to find the smoothest combo.

 

[Lex94]

I haven't used MMO since I was a kid working at a service station (Sans Oregon and New Jersey...remember those?). I will give it a try in this clattering beast.

 

[147_Grain]

Originally Posted By: 05LGTLtd
Pour ~5oz of MMO in the fuel tank before your next fill up if you really want to find the smoothest combo.


A TC-W3 rated 2-cycle oil also contributes to a smooth running engine and it's less expensive than MMO. (I use the Walmart SuperTech brand of 2-cycle oil for $12.15 per gallon.) Both are good products.

http://www.walmart.com/ip/Super-Tech-TC-W3-Outboard-2-Cycle-Oil-1-Gallon/16795065

 

[05LGTLtd]

What's the year, Model, and mileage on this Subaru?

 

[Blue_Goose]

Hmmmmmm. I may have to try this. Interesting you mention a vibration in the gas pedal. I have this in my 2014 Crosstrek with the 2.0 engine that irritating to say the least. It too is a noisy harsh sounding beast as well

Spec for 0w20 though.....any harm in using above combo?

 

[Lex94]

2001 Outback 180K miles

IIRC, The Subaru FB series engines are spec to 5w40 in other markets...I don't know if there are any engine differences. The PYB 10w30 made the engine totally smooth but the PYB 5w20 or 5w30 did not. A 1:4 mix with the MS5K 5w20 was still silly smooth in the EJ25 but a 50:50 or 1:3 mix was not.

Bluesubie would probably be the expert on the FB engine.

 

[05LGTLtd]

Originally Posted By: Lex94
2001 Outback 180K miles


You probably need the motor/trans mounts replaced on that Outback...

Edit: Plugs/wires changed? Cleaned TB and MAF? PCV? Grounds all checked?

 

[fdcg27]

GC always seemed pretty smooth in our '09 Forester.
Ultra 5w30 seems even smoother, but we'll see how it sounds after 6K.
Subarus are not noted for being smooth and quiet, although the 2.2s are smoother than the punched out 2.5, maybe because the block has more metal remaining and is stiffer.
You'll never confuse any Subaru four with any Honda four and it isn't just the firing order and consequent exhaust note.
Even the K24, the roughest four cylinder Honda I've ever driven, is a model of refinement next to any of the three Subarus we've owned.