"We've thrown a rod", "Is that serious?", "Yep."
August 7, 2016 5:56 PM   Subscribe

I have a 1998 Subaru Legacy Outback. I have what I suspect is a significant engine problem. I have data. I have a parts car. I could use some advice.

I have a long-lived 1998 Subaru Legacy Outback. It currently has a 2.5 L 4 cylinder boxter engine on a manual transmission.

The other day something went wonky and I started hearing a repetitive clicking sound from the motor. I got an ODBII error of P0301 which indicated a cylinder misfire on #1. I cleared the error, made sure my oil was topped off, and continued for another day or two until, on my way home, the noise became noticeably more pronounced. I did not see any significant loss in power until I parked the car and restarted it, at this time the banging was significant though the car still started and held an idle. An attempt to test drive it around the block revealed that something was now very wrong; I had virtually no power and the car stalled if I let the RPM drop below 1500.

I am fortunate in that I also have a 1998 Subaru Legacy Outback with a 2.2 L engine on an automatic transmission that has been acting as a donor car for this one for the past year or so. (I've seriously Frankensteined these together to the point where the entire interior, much of the exterior, all of the electronics, the whole exhaust system and the front passenger wheel knuckle assembly have been moved from one to the other. But when Parts Car died the engine was fine.)

So at the time I didn't view it as a huge problem. I've had other cars with cylinder issue in the past so I started troubleshooting by moving parts from the parts car to cylinder 1 on the runner:

- Spark plug: nope. Different spark plug: nope.
- Spark plug wire: nope. Different spark plug wire: nope.
- Coil pack. Nope.
- Fuel injector: nope. Different fuel injector: nope. Thoroughly cleaned fuel injector: nope.

At this point my suspicions started to get the better of me so I also started testing changes on cylinder 2 (same side of the engine) using the same parts I'd been testing on one. Cylinder 2 had no problems with any of the parts suggesting that they were not at fault.

I tested the compression at each cylinder and got about 120 psi on 1, 2 & 3 (#1 surprised me quite a bit because of the initial code) but only about 30 psi on cylinder #4.

I shifted all my attention to that side of the engine. (The banging is loud enough that it is impossible to identify which side the sound is coming from.) Same deal, new plug, new injector, new wire; nope, nope, nope. I had some Engine Restore on hand so I put some directly into the cylinder to see if I could increase the compression. Nope.

At this point I am assuming that it is a busted head gasket, however I swap the antifreeze and there is absolutely no oil in it. Nor is there oil in the cylinder itself. I am getting no suckback on the exhaust, so (according to the Internets) it probably isn't a stuck valve. I spray engine starter around the seams while the motor is running to see if it suddenly levels out which would suggest a gap in the housing around the cylinder letting in air, again; nope.

A neighbor sees me working on it and says in passing "You've got a busted rod". To which I say "fuck" because it seemed like the most reasonable reply.

So, with all of that background, here is my question. Based on the description, is it a problem with the rod? The car will still hold an idle, albeit a noisy one.

My preference would be to fix and keep the 2.5, because it is a more robust engine than the 2.2, but all I really care about it that it runs. So next; assuming it /isn't/ the rod, what else can I check? and / or how can I confirm that it is, in fact the rod. From what I've read, a thrown rod is pretty catastrophic and will usually end an engine. Is the fact that mine is still running a sign that a rod is not the problem?

Assuming that it is a thrown rod and engine swaps are going to be a thing in my near future; how difficult is it to change a motor set up for an automatic transmission to work with a manual? And can a 2.2 properly be fitted to a tranny built to work on a 2.5?

Lastly; and this is getting into the weeds of Subaru engine knowledge; is the intake manifold on the 2.2 the same as the 2.5? Meaning, if I do have to swap, do I have to swap the whole thing, or can I just move the intake out of the way, pull the core from both, and reinstall the 2.5 intake on the 2.2 core?

A big part of the problem is that it would appear that in 1999 Subaru made the transition to the Phase 2 engine type, so many of the videos and information are using those as examples, and the differences are small, but significant enough that I don't want to draw assumptions and I'd rather not have to pull everything only to find that some stuff doesn't fit.

A final caveat; I am poor as dirt AND I don't actually know as much about cars as the above might suggest. Because of the former, over the years, I've had to become more proficient at the latter. So I'm not worried about trying any of this, but what I can't do is throw money at the problem. In any way. I can't afford a new car, I can't afford to take it in to be serviced. It will either be fixed by me, or sent to the junk yard along with the parts car.

I do have a good sense for mechanical troubleshooting and a willingness to really bloody my knuckles on every sharp and rusty edge doing whatever it takes to to solve the problem. I also have a comprehensive set of tools and access to an astonishing assortment of much better tools (Yay! Makerspace!) if the need arises, but in this I'm limited by what I can transport home as I can't get the Subaru there.

I'm also in a social isolationist point in my life, so I can't expect help from anyone but myself. But I have time, parts, tools, and an obstinate stubbornness that comes from never being able to pay for a fix and so by necessity learning how to do them myself.

Can it be done? How can it be done? Which should I do? Can I train my dog to fix it? Should I just arson the whole thing and collect the insurance (Whoa! Kidding. Totally kidding! Though when a partially unseated fuel injector over-pressured and started spraying a fine mist of gas everywhere for a few seconds, I couldn't help but giggle maniacally.)

But I'd love it if someone out there knew enough to spare me waking down some dark, stupid, and pointless paths if I can avoid it.
posted by iconomicon to Travel & Transportation (11 answers total) 3 users marked this as a favorite
 
If you have no compression, there is an audible banging and it is getting worse fast, then you have damaged something in the cylinder of No.4. It's probably pooched. So internally, something between the crank/piston/connecting rod is broken to the point that the cylinder wall is damaged. Just a ticking MAY have been a piston ring or a valve problem, but the banging and lack of idle suggests significant internal damage. Nothing you change on the outside will make any difference. It is all internal and likely that the cylinder wall itself is damaged - is the engine is pooched.

"My preference would be to fix and keep the 2.5, because it is a more robust engine than the 2.2"
It is not robust. It is fucked. :)
I would find it very unlikely that the parts from the one engine will 2.2 will fix the issues with the 2.5. Besides, you'd have to remove and completely disassemble both engines to even get to that stage, which is far more work than would be sensible.

Your best bet is to get a replacement 2.5 Engine from a breakers yard. Not a reconditioned, if money is tight, just 'another one'. Otherwise you need a full engine rebuild on the existing 2.5L engine, and it may not even be fixable - you can replace the cylinder 4 broken parts, but it is almost certain that the block itself would be damaged.

how difficult is it to change a motor set up for an automatic transmission to work with a manual? And can a 2.2 properly be fitted to a tranny built to work on a 2.5?
Potentially very difficult, potentially not. But it is certainly much, much more work than getting one from a breaker's yard because the 2.5 to 2.2 swap may mean all the sensors are different, or the ECU is not compatible and before you know it you have to swap engine looms and all kinds of drama. Better to get a donor 2.5L. Which may only be $1000 plus shipping. Sell or scrap the other Legacy to cover the costs.
posted by Brockles at 6:38 PM on August 7, 2016 [7 favorites]


disclaimer: I know nothing in particular about Subarus.

From the compression reading in #4, obviously something wrong there. Possibly broken connecting rod or holed piston. The only way to really know is to take a look. This involves dropping the oil pan. If nothing obvious there, then remove the head, unbolt conn rod and push piston up and out. With the noises you describe, you'll probably see something interesting.

The problem with doing this is the cost to put it back together. You'll definitely need a gasket set, which isn't cheap. You'll need antifreeze and oil. If there's anything wrong with the head, you'll need machine shop services.

I just read brockles post and agree with everything he says. You may want to take it apart for the adventure, but the chances of getting it working, especially with no money, are pretty slim.
posted by H21 at 6:42 PM on August 7, 2016


But I'd love it if someone out there knew enough to spare me waking down some dark, stupid, and pointless paths if I can avoid it.

By the way. My BEST advice for not going down this path is knowing when to walk away from all or part of a project. You've already wasted all the diagnostic time you spent on that engine, because none of it was going to help. Don't waste any more. That engine is toast, find a replacement. Trying to convert to 2.2 is insane unless you REALLY know what you're doing. Find a replacement 2.5 engine.
posted by Brockles at 7:09 PM on August 7, 2016 [2 favorites]


Response by poster: Brockles, your wisdom feels wise, and I believe a lot like the direction I'll end up going. I'd like to clarify one minor point of my original post; this is a zero-cost build/ repair, but I'm being a little bit flexible with the term; I'll pay for new gaskets, oil, antifreeze, plugs, wires, etc. I view that as a necessary cost of survival if need be, but what I can't do is throw several thousand at a new beater or really, even an engine; so maybe I can drill down a little.

I look at Car-Parts.com and I see that 2.5s can start in the $1800 range and drop as low as a couple hundred for the "core". I just want to make sure that what they mean by the core and what I do are the same thing; I'm considering the core everything below the intake manifold, above the exhaust manifold, and before the transmission (though I don't know if that would include the flywheel). Basically covering the bits on mine that are roached (cylinders, pistons, valves).

Is that right? I've never bought just an engine before, let alone a very specific but large part of one. All the ancillary parts, like the water pump, alternator, starter, radiator, etc all seem fine on what I've got, so I figure those are just bolt on and go. But would a core include the timing components, and more importantly, would those be already timed?

That, I think, more than anything is my fear with this; everything else I've seen seems -more or less- intuitive. But the timing belt and the associated precision set up of it keeps feeling a little bit like magic in the videos I've watched. I suspect that being there and seeing it in person would probably make it less spooky, but I'm working with what I've got.

Scrapping the parts car will almost assuredly be my next move, particularly if I can't pick off any more bits to get this one running, but since I'm going to have to be gutting everything anyway if I'm going to install a new 2.5, would it be worth the exercise to pull the 2.2 just to see how much I break before I pull the non-functioning 2.5? I'm thinking about the just-for-the-experience angle. I've never swapped an engine and it would seem if I've got two that I either can't use or can't make worse (barring the aforementioned needed ancillary parts) is there anything to be gained, information wise, by the effort, or is it really just going to make a mess of what is already a mess?

Probably something I'll have to answer for myself I suppose.

But being that I'm moving into uncharted territory, does anyone have any suggestions on how to procure a cheap but functioning 2.5? Is searching local best, or is it worth it to find the most suitable in my price range and have it shipped? Car-parts.com any good or are there better general metasearch tools out there? It is just the first one i found.

Oh, and should I be looking for a 2.5 that was on a manual, or does that part at least fall into something that can be moved from the old one to the new one? I ask because I know I'm going to see a lot that list as for AT and I don't want to rule them out if it is just fairly simple parts move.
posted by iconomicon at 7:38 PM on August 7, 2016


Just so you know, that's *Brockles* right there. His wisdom feels wise because it is wise.
posted by herrdoktor at 7:46 PM on August 7, 2016 [2 favorites]


iconomicon: "I look at Car-Parts.com and I see that 2.5s can start in the $1800 range and drop as low as a couple hundred for the "core". I just want to make sure that what they mean by the core and what I do are the same thing; I'm considering the core everything below the intake manifold, above the exhaust manifold, and before the transmission (though I don't know if that would include the flywheel). Basically covering the bits on mine that are roached (cylinders, pistons, valves).
"

What you are describing (but including the intake manifold) I'd a call a short block; a core is something of unknown providence (unless it says rebuild-able) that could be rebuilt if one was so inclined. You currently have a core for example.
posted by Mitheral at 9:03 PM on August 7, 2016


I'm considering the core everything below the intake manifold, above the exhaust manifold, and before the transmission (though I don't know if that would include the flywheel).

Yes that should be correct, but you are best off checking with the person you are buying from, because some people have weird definitions. Especially if something that is normally included (say the flywheel is expensive) suddenly isn't included because they can make an extra buck calling it an 'extra'.

I'd a call a short block

This is an example of the problem. A short block, to me, is a block, sump and pistons/crank etc. No cylinder head. Definitions are not necessarily universal.

HOWEVER. If you buy a core engine (which should be head, block, sump and all internals in my book - a sealed engine ready to go minus manifolds, alternator, starter etc) is probably all you need. But in your position, getting a complete engine will make sure you don't fall foul of weird stuff like different sensors or oddness. You never know. It's probably the cheapest way of getting that many spares (like an alternator, for instance, and a starter) that you may need to keep this beast alive. Although I know your balance is price versus price right now.

Of note - you will be getting an engine of almost certainly unknown provenance. I'd consider replacing the timing belt before installation an essential bit of insurance. If you have a manual and a timing light (which may not even be needed if the engine is just timed on notches or marks) then it isn't that hard. It is not black magic. Also, replace ancillary belts if you can - maybe also the water pump if they are cheap. MUCH easier to do on an engine on the floor than in the car. Consider the option that if the clutch is anything other than 'in very good condition' you may want to change that while you are there to save work later too. Personally, I don't believe i changing just the friction plate, but replace the whole assembly as one. I've had too many bad experiences with springs on pressure plates going soft and having to re-pull the trans to do it again. Either way ABSOLUTELY put a new clutch release bearing in there. They are cheap as chips.

would it be worth the exercise to pull the 2.2 just to see how much I break before I pull the non-functioning 2.5?
On the contrary, I'd leave a complete installation so you can remember where everything goes. Start with a clean space, a good crane and lay out stuff on cardboard and label everything and use ziplocs for bolts grouped by location. With a methodical approach there is nothing magical about an engine swap if you have the time and the tools. Having a decent engine crane is important so you can lift a little... inspect 360... lift a little... inspect 360 etc so you don't break anything or snap any wires.

Is searching local best, or is it worth it to find the most suitable in my price range and have it shipped?
Shipping one gives you more choice. Getting one local means much easier recourse if there is an issue. But I'd ship one with the lowest mileage, if it were me. Or pull it myself locally at a pick and pull if I had the use of a truck and a friend.

Oh, and should I be looking for a 2.5 that was on a manual
That I can't help with, as I don't know. It is possible there is a different vacuum system or something weird on an auto (or something more major) that is different so an AT would be safer, but it may be no problem at all. A subaru specialist or even talking to a guy at a dealer may be something worth doing. Subaru specific forums would be worth a quick question for that maybe.
posted by Brockles at 9:17 PM on August 7, 2016


For example one common major problem with taking an auto engine and putting it in a manual car is the crank not being machined for a pilot bearing. So definitely check with marque knowledgeable people before attempting that sort of swap.
posted by Mitheral at 9:49 PM on August 7, 2016


Hi, I think Brockles has you covered on a lot of the practicalities, but some encouragement for you:

You are working on a car with a large and enthusiastic following. Dig into the web, you will find some kid who has done an auto-to-manual transmission swap and detailed it. This should give you the info you need to know if you can search for any engine or just one originally from a manual. My gut says any engine will be fine, they are designed for both options. I myself did an auto to manual transmission swap on a similar vintage Accord and EVERYTHING in the vehicle was setup for both, as you would expect is is just a difference of what parts are installed along the assembly line.

Secondarily, I would be totally un-surprised to find that the 2.2 will bolt right up to the transmission and that the harnesses, etc, would require no or minor re-work to allow you to plug in an ECU for a MANUAL 2.2 and away-you-go. Look around online to see if anyone has done this swap as well with clear notes/pictures.
posted by no1hatchling at 9:49 PM on August 7, 2016


I know very little about cars, but in reading your question, maybe the least expensive option is to swap cars, parts to running. You say the engine is working in the parts car albeit an automatic. Might it be easier to swap back the interior items and just drive the automatic 2.2?
posted by AugustWest at 11:54 PM on August 7, 2016


If both the 98 Subies were not superceded by new models until more than say 6 months later, and/or are close to identical build dates, there is a good chance that they are similar to the point of interchangeability, as you have largely discovered. Anecdata: my 2003 2.5, a late build immediately before a changeover in models, has a 2004MY clutch assembly, not the one the Subaru workshop manuals/parts listings say it should have, and I hope I never get to find out what else may be different!

You can pull the 2.2 engine and check that the bellhousing (bolt spacings especially) and spigot bearings etc are the same, and check the sensors (though they could be replaced with the 2.5 sensors. The only thing that would worry me would be the AFR, which measures the air and fuel being used by the engine, and is used to ensure the air/fuel ratio is correct. I would use the 2.5 injectors and 2.5 MAF on the 2.2, with the 2.5 computer. One of the Suby forums will no doubt be able to assist in this - it would definitely be worth checking these out and joining a couple to ask questions.
posted by GeeEmm at 4:50 AM on August 8, 2016


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