the Outback still lives, still with the 2.5.

[Bserk]

Ive been putting off posting this, since either: 1) I completely mis- diagnosed and exaggerated the knocking issues of my engine, or 2) Ive gotton some kind of reprieve and I will jinx myself by bringing it up. Real short version: 96 OB, 2.5, bought with head gasket issues and replaced head gaskets, etc., and then drove car all summer with no issues other than slight piston slap on cold start. Several weeks back, I posted that the engine was knocking loudly when started and asked opinions of what was happening. I had already decided that the bottom end was failing and several replys to my post made that sound like a plausible situation. Ive been in the automotive tech trade for 30 years and nothing Ive ever been around has made that much of a ominous sound without being on its way out....lol. I know that the Nissans, that Im most familiar with, have never 'knocked' that loudly without having serious internal problems, and been close to flying apart by that time.

 

Well, I decided I had nothing to lose, other than a tow bill when it blew, if I kept on driving it. And so I have. And it still scares me when I start it on a cold morning. It makes the hair stand up on my neck, man. Its just not normal. But drive that ole' girl for a few miles and slowly but surely, it becomes ALMOST quiet. It gets as quiet as it was in the summer on cold start. Still a little 'rap rap rap' but not the scary knock... I was still convinced that things were getting too loose and I was on borrowed time. (and still looking for a good deal on a 2.2 to replace my engine with)

 

Last week, we took in on trade at the Nissan shop where I work, a 2003 Forester. I had to move this car after a snow storm and got to hear it on a stone cold (5 above zero) start. It is almost as bad as my Outback! This car has 40,000 miles and appears to be a well maintained car. Its a 2.5 and I assume the bottom end is the same or similar to my car. Is it possible that Im just way too paranoid about Subaru engine noises? Is it possible that this Forester could be as 'sick' as my car (I would find it hard to believe that, the Forester is a clean car) Im actually encouraged , after hearing that Forester, that my ole Outback might stick together as is for a while. Or, as I said above, I just jinxed myself and she blows tomorrow morning... Quite a ramble there, but if you got any opinions I'd love to hear them.

[nipper]

This is piston slap. Piston slap can sound hideous when the engine is cold, but as long as it goes away once the engine warm up its harmless. Rodknock on the other hand never goes away.

 

Subarus are known for slap. They made the piston skirts too short (for emissions and free-er reving). Some engines are really really horrible with it (GM has lawsuits).

 

nipper

[johnceggleston]

Well, I decided I had nothing to lose, other than a tow bill when it blew, if I kept on driving it.

:banana::banana::banana: we have a winner!!!!!

 

i bought my 97 OBW - 98k miles with engine noise and fully expected to replaced the engine, i already had the 2.2 to go in it. but once i read about piston slap, i decided to drive it. i can always do the swap later, and i really love getting "free" miles out of my outback. so far 23k free miles and counting.

 

now my ej22 is going in my wife's newly bought 97 GT w/ bad gaskets. so i figure about 2 months after i swap in the ej22, murphy will show up and my OBW will give up. oh well. still better than driving a dodge mini-van.

[OB99W]

[...]drove car all summer with no issues other than slight piston slap on cold start. Several weeks back, I posted that the engine was knocking loudly when started[...]scares me when I start it on a cold morning. It makes the hair stand up on my neck, man. Its just not normal. But drive that ole' girl for a few miles and slowly but surely, it becomes ALMOST quiet. It gets as quiet as it was in the summer on cold start. Still a little 'rap rap rap' but not the scary knock... I was still convinced that things were getting too loose and I was on borrowed time. (and still looking for a good deal on a 2.2 to replace my engine with)

As you already know, the 2.5 engines are prone to piston slap. Not all of them develop it (at least, not to the extent that it's scary ), but on those that do it can be fairly loud when the engine is particularly cold; it then takes a while for the pistons to expand enough to take up the "slack".

 

 

Last week, we took in on trade at the Nissan shop where I work, a 2003 Forester. I had to move this car after a snow storm and got to hear it on a stone cold (5 above zero) start. It is almost as bad as my Outback! This car has 40,000 miles and appears to be a well maintained car. Its a 2.5 and I assume the bottom end is the same or similar to my car.

Piston slap tends to be most noticeable in the mid-to-high 1k rpm range. On a truly cold start, the initial idle would probably be in that range (although a quick throttle stab will usually drop it back). Oil viscosity plays a part in this -- heavier-than-spec oil usually will quiet cold-start piston slap somewhat, but the rest of the engine is typically better off with rapid lubrication provided by the "proper" weight.

 

 

Is it possible that Im just way too paranoid about Subaru engine noises?

If the noise is especially prominent in the rpm range I mentioned above, and pretty much resolves as the engine warms, it's likely to just be piston slap. Your engine may be one of those more prone to it.

 

 

Is it possible that this Forester could be as 'sick' as my car (I would find it hard to believe that, the Forester is a clean car) Im actually encouraged , after hearing that Forester, that my ole Outback might stick together as is for a while. Or, as I said above, I just jinxed myself and she blows tomorrow morning... Quite a ramble there, but if you got any opinions I'd love to hear them.

Sorry, my crystal ball is murky today. Considering that if the bottom end is too loose and needs attention it would require major work, I'd stick with the concept of running the 2.5 until it either stops scaring you or bears out your concern. (I have no advice to give on the Forester. )

[screwbaru2]

Keep driving it! Aside from the HG issue the 2.5 will take a beating. I drove mine for 7 months w/ a bad HG 600 miles per week, the last week the themostat was shut, temp needle pegged! Towed the last 10 miles.

[sjbien]

Ive been putting off posting this, since either: 1) I completely mis- diagnosed and exaggerated the knocking issues of my engine, or 2) Ive gotton some kind of reprieve and I will jinx myself by bringing it up. Real short version: 96 OB, 2.5, bought with head gasket issues and replaced head gaskets, etc., and then drove car all summer with no issues other than slight piston slap on cold start. Several weeks back, I posted that the engine was knocking loudly when started and asked opinions of what was happening. I had already decided that the bottom end was failing and several replys to my post made that sound like a plausible situation. Ive been in the automotive tech trade for 30 years and nothing Ive ever been around has made that much of a ominous sound without being on its way out....lol. I know that the Nissans, that Im most familiar with, have never 'knocked' that loudly without having serious internal problems, and been close to flying apart by that time.

 

Well, I decided I had nothing to lose, other than a tow bill when it blew, if I kept on driving it. And so I have. And it still scares me when I start it on a cold morning. It makes the hair stand up on my neck, man. Its just not normal. But drive that ole' girl for a few miles and slowly but surely, it becomes ALMOST quiet. It gets as quiet as it was in the summer on cold start. Still a little 'rap rap rap' but not the scary knock... I was still convinced that things were getting too loose and I was on borrowed time. (and still looking for a good deal on a 2.2 to replace my engine with)

 

Last week, we took in on trade at the Nissan shop where I work, a 2003 Forester. I had to move this car after a snow storm and got to hear it on a stone cold (5 above zero) start. It is almost as bad as my Outback! This car has 40,000 miles and appears to be a well maintained car. Its a 2.5 and I assume the bottom end is the same or similar to my car. Is it possible that Im just way too paranoid about Subaru engine noises? Is it possible that this Forester could be as 'sick' as my car (I would find it hard to believe that, the Forester is a clean car) Im actually encouraged , after hearing that Forester, that my ole Outback might stick together as is for a while. Or, as I said above, I just jinxed myself and she blows tomorrow morning... Quite a ramble there, but if you got any opinions I'd love to hear them.

 

 

i don't know what i think of the piston slap issue. two years ago i bought a 2001 OB with 97k and it had a loud tap when starting. the dealer said not to worry, they all sound that way.

25k later the tap got worse, a misfire developed and, to make a long story short, i found i had a blown HG and a toasted cylinder, scored and burned. the mechanic who tore it down thought the news was typical and surprised by how awful the cylinder looked. so was that cylinder talking to me all along?

i am now driving a rebuilt 2.5 and there is no tap whatsoever when cold. so is this piston slap the real thing or a myth. should it prompt an owner to at least check compression? or drive it until the problem declares itself?

[idosubaru]

compression tests are easy enough to do, so it's not a bad idea, though might not be worth paying someone to do it. long answer to follow....

 

your original issues 25k prior was not head gaskets. if they're blown they can not last that long without any other issues...overheating, loss of coolant, etc. whether or not that original issue is related to the eventual failure i do not know but head gasket issues are so common on these, as is the piston slap, that trying to associate the normally benign piston slap with the much more serious head gasket issue probably won't gain us anything. because you'd never want to suggest to people that piston slap (common but almost always insignificant) may lead to head gasket problems (always significant)....even if the chances are really small, it's just not worth it.

 

should it prompt an owner to at least check compression? or drive it until the problem declares itself?

compression tests often turn out fine, they are not very good for diagnosing *this type* of head gasket problem. if it was significant enough to show on the compression gauge it would be hard to believe the owner isn't experiencing overheating or coolant loss...again, with this motor in mind.

[crazyhorse001]

My Lego had "piston slap" from the day I bought it with 114k.

The colder the outside temps, the louder it knocked. It always went away after 5-6 mi. It sounded BAD! It also got $1k "knocked" off the price.:cool:

[Bserk]

I guess the majority here would call it the dreaded piston slap then! Im in for the long run with this car, it was bought for use as a winter beater and became my favorite daily driver after I got it on the road. It has a remote starter too, so when its cold outside, Im going to remote start her and let her rap to her heart's content. LOL! I'll be inside ignoring it....

 

We are having a good winter here so far, unlike the last few years we have already had a couple good snow storms. I put 4 new WinterForce studded snows on her this morning. A generic brand (at least I had never heard of them) but came highly recommended by the distributer. $299, studs and tax included. They look like great tires, I'll post how they work in the next storm.

 

Thanks, once again, for all the replies. This site is the best.

[WoodsWagon]

Our 98 outback has the piston slap bad. When we bought it, it had blown head gaskets, so I didn't want to run it up to operating temp to see if the slap would go away. I pulled the motor, and when I had the heads off, I could rock the pistons in their bores a bit. Didn't remember being able to do that with the 2.2l. Anyways, like a fool I put it back together with new gaskets. It raps something vicious when cold, then settles down to a loud diesel engine rap when it warms up. We took it out to Wyoming and back, a 5,000 mile roadtrip. It held up fine. Other than the embarrasing noise, it runs fine, returns expected gas millage, and doesn't smoke, so.... we ignore it.

[ShawnW]

I rebuild these engines every day. When I build them I measure the piston clearance and size the pistons to their bores.

 

A growing percentage of the EJ25 engines are not suitable for a rebuild. The bores are egg shaped from the overheats or deformed by something.

 

Subarus first Ej25s (in 1996) were a drastic difference in piston skirt length and they have done nothing but make them shorter since. The 96's rarely slap but they still are found with it.

 

It is my opinion that the EJ25 engine is a decent one. Its still a decent engine but we are spoiled by the quality of the previous designs. EA81, EJ22, EJ18.....for example.

 

The real kicker.....

 

Find a 1996 model year car with the EJ25 DOHC Hyd lifter engine that has a manual transmission behind it. Curse Subaru for their tenacity to put their best engines in front of Auto trannys. Ea81T, Ej22T, SVX....GRRR!

[idosubaru]

Curse Subaru for their tenacity to put their best engines in front of Auto trannys.

and auto trannys in some of their neatest vehicles - SVX & SUS

[Gloyale]

Find a 1996 model year car with the EJ25 DOHC Hyd lifter engine that has a manual transmission behind it. Curse Subaru for their tenacity to put their best engines in front of Auto trannys. Ea81T, Ej22T, SVX....GRRR!

 

Because their 5 spds are clunky, prone to grinding, have long throws, and tend to be noisy. When you pay for a top of the line model, it should be refined.

 

Plus, automatics are better able to keep the power to the road in real world driving, espescially in the mud and snow. It's just alot more sophisticated piece of engineering than the manual with a 30 year old gearbox design.

[98obster]

It's been cold here in Northern Colorado lately. I check my dip stick once a week (that would be the car's :/) and notice that there is still a high mark where oil pressure has pushed up the oil and sticks to it. I can only hope that there is that same thin film of oil all over the engine. I have a fair amount of slap when the engine first starts but quickly subsides as the engine warms. The lifters have their distinct sound and it takes a couple seconds for the oil to get to them.

 

Yeah, for as bullet proof as the ej22 is described (and the 2.5 as well), for a minute it does sound like some Trabant 2 cylinder on the way out. Maybe not as bad as this though:

 

How many cold starts does it take to get to the bottom of a subaru engine? I don't know, go ask Mr. Nipper.