2000-2004 ej25 non turbo bottom end reliability (high miles)

[dreyko]

Hello everyone,

I'm the owner of a extremely clean 2003 Subaru Outback 5 speed wagon. I've only vehicle since 2016 when I purchased it with 201k miles, it is currently around 280,000 miles.

It has had the head gaskets replaced, like they all have. And it does consume a fair bit of oil. I'm not concerned about minor failures, as I am an accomplished mechanic and able to repair the vehicle on the road if needed.

However I do a lot of long distance driving with this vehicle, I have taken it to Toronto, and tampa, and I'm planning a trip to the Grand Canyon next year presuming the pandemic allows. Most of my traveling is in excess of 4 hours one way.

I know the turbo engines are common for bottom and failures, how common is that on the naturally aspirated engines? I've heard a fair deal about spun bearings and the occasional broken connecting rod story. I'd rather not be surprised with an unexpected failure oh, but I also don't want to replace a good functioning engine if I don't need to.

While the oil consumption is manageable I am seriously considering replacing my pistons in the next 20-30k miles, I'd rather not have to do a full overhaul if I can avoid it though.

I have seen a few posts about four and five hundred thousand mile vehicles, how common is that? Being that my car is a rust-free example with a manual transmission the only major failure point that I would receive would be the 2.5's bottom end.

[montana tom]

My work vehicle is a 2000 rust free 5 speed car. currently at 311,000. I routinely drive 4 hrs or more one way to work. 

I would drive it to Caribou, Maine   or Key West FL today.

Yes it uses oil as well.  Clean or change the pistons. Use new  NPR rings. 

As long as they are not allowed to get hot they are truly 400-500,000 mile motors.

Tell tale on these motors is a rod bearing rattle at startup and also noticeable at float rpms while driving.

If you start hearing that, start looking for a replacement longblock. 

[dreyko]

Interesting. I do have some light lifter noise at low throttle/ soft cruise speeds. Its been doing that for at least 60k miles. Never thought much about it. 

Also being a 5 speed it does the piston skirt rattle if you come off the clutch without giving it enough throttle.  However every 5 speed subi I've ever driven will do that.

Hope I am not misreading the signs.

[idosubaru]

It needs oil control rings, not pistons but I wouldn't put significant time money or time into a 280k EJ25 bottom end.  I'd just keep adding oil, it's just getting past the oil control rings, not a big deal.  But if you're really itching too - install new oil control rings and only address the pistons if you have piston slap in which case knurl them. 

The stranding items at that age and mileage is commonly timing pulley/component, alternator, or fuel pump.  OEM is old, $$$$, and aftermarket is a roll of the dice. 

Replace all the timing components - pulleys, belt and tensioner - with Subaru OEM and call it good. 

Replace or have a spare knock sensor on hand, they're cheap and commonly fail. 

[Numbchux]

My daily is a '00 Outback, currently about 335k miles. It has lots of issues, but most are due to it's life in MN (rust...).

I understand that at really high mileage, the main bearings get beat up, and not worth line honing. I put an actual oil pressure gauge on it so I can make sure that stays good (the switch for the warning light is only a few psi...).

[el_freddo]

We have an EJ251 in my sister’s RX liberty. It’s now got about 450,000km ad still going strong. 

It mainly does country kms so it always gets a full warm up and a decent run, unlike many urban vehicles. 

Last head gasket job I replaced all the valve stem seals and lapped the valves while at it. 

You should adjust the tappets if you have “lifter” noise. These don’t have hydraulic lash adjusters, they’re solid and need adjustment from time to time. 

To me, bottom end = solid. Don’t redline it regularly (what’s the point of that, ring the neck of anything and it won’t last long!)  The rod throwing is from the EJ25D era shortly after a head gasket job from what I’ve read. @GeneralDisorder will confirm, but I believe it’s due to bearing damage from use with a blown HG with coolant in the oil. 

Cheers 

Bennie

[GeneralDisorder]

Those 2000 to 2005 NA Legacy engines had the smallest oil pumps Subaru ever used - 7mm. Not great long term. 

These engines die from a lack of oil flow to the rod bearings - this is due to the engine block main bearing journals being opened up from thousands of miles of crankshaft flex and being made of soft cast aluminium alloy that has a similar density to Oak. 

As the main line clearances open up, they drop oil pressure and volume to the rods eventually leading to rod bearing failure. 

Subaru is well aware of this effect - take a look at the failed Subaru diesel engine - they knew the aluminium block main journals would never hold the cylinder pressures of a diesel, so they cut out the mains and made the journals from cast iron inserts that are bolted into the aluminium block. Alas they crack and this was the end of the diesel Subaru experiment. They were junk. 

280k is pretty well done. Stick a fork in it. Without a main line hone it's a waste of effort. Best option if you want to keep the car on the road is a reman short block from Subaru for $2350 and comes with a 3yr / 36k warranty. Or a new short block - can still get those as well. Main line hone, while possible, isn't economically viable for a non-turbo block.

GD