Subaru Outback Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
My 98 legacy outback engine has lost compression (one month before I pay it off :rolleyes:). I am considering what to do so I am asking for advice. Could this be a blown headgasket (I believe that it is the original and I am at 180,000 miles)? If so, how do I know it has? If it is something else, can I fix this engine or should I look at getting a different one? I would really appreciate help on this.
 

·
Registered
Joined
·
16,964 Posts
you haven't offered much detail.

very generally speaking, bad headgaskets in soobs aren't 'necessarily' associated with loss of compression.

post your city and someone may be able to suggest a shop to help with diagnosis/repair.

if you plan to fix this yourself, let us know; miles/condition of the car, if you're the original owner, what the exact symptoms are now and what led-up to the problem, time since last timing belt change.

these would be a good start
 

·
Registered
Joined
·
17 Posts
Discussion Starter #3
My car has 180,000 miles on it and is in fairly good condition. I have had to replace the clutch, spark plugs, spark plug wires, ignition coil, starter, fuel pump, PCV valve, and the oil compression switch.
I am not the original owner, I have only had it since June 2010. I do not know if the timing belt has been changed. I have had the P0304 code pop up for nearly a year. After having my mechanic dad and a mechanic friend check it out, we thought it was a computer glitch since engine performance was not affected. A month ago, my engine started running roughly, and my CEL started blinking occasionally. A few weeks ago, I borrowed a code reader and got three codes: P0303, P0304, and P0420. I then had a local service station check it out. The mechanic said that cylinder 3 had lost compression. I can't remember exactly what he said, I believe he said it was from the cylinder head and that a sleeve had worn. I will get back with him to find what he actually said.
 

·
Registered
Joined
·
1,401 Posts
knowing one cylinder has ''lost '' compression isn't a lot of info.
how low is it?
how are the other 3?
what do the plugs look like?

there are a list of things it could be, but with a little more info we can help narrow it down.

1 - it COULD be head gasket related, but that usually causes overheating. so probably not.

2 - it could be a slipped timing belt, a compression test on all 4 would give more info. not uncommon for one side of the engine to be ok and one side to have low compression.

3 - it could be a burnt exhaust valve, probably on #4. a compression and leak down tests would show more. holding a dollar bill on the tail pipe may show a burnt valve if the bill is ever ''sucked'' back in toward the tail pipe. improper valve adjustment can cause a burned valve.

4 - it could be cheap plug wires. these engines are very picky about plug wires and cheap wires can cause headaches. subaru wires are recommended or HIGH QUALITY alternates.

5 - it could be bad plugs, some plugs are known headaches for these engines. NGK plugs are recommended, check your manual for the correct one.

i would replace the plugs and wires if they do nor meet the specified standard. and if that does not help you may want to have your shop do the compression and leak down tests. get the results in writing and report back.

the p0420 is likely the result of 2 cylinders misfiring . or possibly an bad o2 sensor. but i would address the misfire first.

some of the possible causes are easy to correct. some are not. but the price difference between bad head gaskets vs. a burnt valve isn't very much. maybe only $100 or less for only one, but several hundred for a complete valve job. but a shop is going to charge $1500 - $1800 to do the head gaskets, probably.

an engine swap may be less money. but you know the history of your current engine and you will probably not know the history of a replacement engine.

for used engines look here, www.car-part.com
 

·
Registered
Joined
·
17 Posts
Discussion Starter #5
Thank you for the information. I will be looking into it over the next few weeks. I will try to remember to post the results.
Also, my mechanic did not keep detailed records, so I do not know what exactly is causing the lack of compression.
 

·
Registered
Joined
·
12,299 Posts
First step - pull side timing belt covers (only takes a few minutes) and make sure the timing belt is operational and the cam pulleys line up properly. this only takes a few minutes.

Next step is - have the compression numbers taken and post the results here for all 4 cylinders.

We don't know if he simply guessed or the gauge is proper or the loss is within limits or not....best to see the numbers.

Does the car turn over and run at all?
 

·
Registered
Joined
·
17 Posts
Discussion Starter #8
I finally got around to the compression test. I pulled out all of my spark plugs, then tested each cylinder.
Cylinder 1: The spark plug was worn, but other wise fine.
It had 180 PSI.

Cylinder 2: The spark plug had a lot of carbon on the white part and on the spark plug wire boot. The gap was wider then specified.
It had 150 PSI.

Cylinder 3: The spark plug had a wider gap than specified and the white part had some rust coloring where the white part meets the threads.
It had 120 PSI.

Cylinder 4: The spark plug had a little bit of carbon on the white part.
It had 32 PSI.
 

·
Registered
Joined
·
12,299 Posts
Good job. Did you repeat cylinder 4? Far off cylinders should be repeated since it's easy to get a bad read on a compression tester especially on that motor with the buried plugs.

Battery stayed strong or you were connected to anther power source - meaning I hope you didn't test them in that order and the compression just got weaker due to the battery draining...180, 150, 120, and 32?

those numbers rule out a timing belt.

It's probably a valve hanging open or possibly some other valve issue. You could do a leak down test and probably will hear compressed air escaping into the exhaust ports or possibly intake. Most EJ heads I pull, even perfectly running engines, have valves that aren't perfectly seating and leak some.

If it is a valve,t he proper repair is repairing the head. Or replace with a known good, used head - fairly easy to find due to the EJ25D lower end bearing and headgasket issues. That's fairly expensive though - you're talking $1,200 - $2,000 depending where, prices, and what all is done.

I'm currently rebuilding a head and wish I would have just bought used heads - it's getting expensive quick with new valves, etc.

used heads:
98 DOHC Heads - Ultimate Subaru Message Board
I should have a set too if you're interested.

I've done that a number of times - $100 for a head instead of $300-$500 for a valve job and new valves, valve guides, etc.

I wonder if there's a massive cleaning cycle where you could get some heavy detergents/cleaner on those valve seats/faces. Filling the intake would take care of the intake valves...not sure about the exhaust since those ports face down and will just drain into the exhaust. I would ask and look for some folks that have done/seen this before and see if you have some options in this direction.

It still could be a slipped belt. Sounds unlikely but it would be good to know since that would essentially be a free or very cheap repair (minus maintenance costs which a timing belt is due anyway and I hardly consider that a repair).

Another option is an EJ22 swap. $300 engine, $100 timing belt kit and some ancillary items and you've got an engine ready for another 100,000 reliable miles for under $500 bucks. Then sell your Ej25 block for $500 and the parts were free. You'd end up with a more reliable engine probably since it's less likely to have headgasket or lower end bearing issues.

I just did this for a friend, picked up an EJ22 for $300 and installed new timing belt, tensioner, pulleys.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #10
I redid cylinder 4 only to get 40 psi. I am currently looking into getting a leakdown test kit.
Also, I discovered the source of the cylinder 3 misfire code. I found oil on my number 3 spark plug, so I tested my spark plug wire. It had a resistance of .9 kilo-ohms. My dad and I believe that this is the source of the misfire.
I have a question though, does anyone know how or why I would have heavy carbon buildup on my number 2 spark plug and spark plug boot and a light carbon buildup on my number 4 spark plug, but have my 1 and 3 spark plugs be clean? This has puzzled both me and my dad.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #11
After talking with a mechanic acquaintance of mine, I will be rebuilding my engine. He said that due to the wide variation of the pressures in my cylinders and the mileage on my vehicle; the only way to fix the problem is to either rebuild or replace my engine. Thank you to everyone for your counsel and advice in this.
 

·
Registered
Joined
·
948 Posts
Any updates on the build?

Andre
 

·
Registered
Joined
·
17 Posts
Discussion Starter #13
Unfortunately other things have come up that needed my attention. I am still looking into whether to replace my engine or have a pro rebuild it. I would rebuild it myself, but since my garage is unheated, I do not want to mess with cold metal in the middle of winter.
 

·
Registered
Joined
·
288 Posts
I would try to find a replacement engine first. Do search for 2.2 swap, which is a good alternative for you. Replacing all the usual stuff while out.
Add in the cost of a heater for work while in the garage.
Being in North Dakota, I shudder at what your temps are!

O.
 

·
Premium Member
Joined
·
11,878 Posts
Check with your shop and see what kind of price he can give you on a rebuilt engine from LKQ. They come complete block and heads and carry a 3 year/unlimited mileage warranty. First time it needs to be swapped, no questions asked. In order for the warranty to be valid, it has to be installed by a professional technician at a licensed facility and you have to follow up with the maintenance as required on the Subaru schedule.

Yes, it will come with the updated MLS gaskets. I just did a complete swap of a SOHC in a Forester for I think $4000 OTD.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #16
After getting a quote of $6200 to rebuild my engine, I have decided to get a new engine. My searching has shown that a decent JDM motor would cost around $1200 including shipping. Unfortunately, some expenses have come up and I will have to delay purchasing the engine for a few months. I plan to get some of the necessary parts in the meantime.
I have heard that I should definitely replace the timing belt, pulleys, water pump, and spark plugs. Is there any other part I should look into replacing?
 

·
Registered
Joined
·
17 Posts
Discussion Starter #17
Update

My engine had a bad head gasket. I replaced my motor with a JDM. I replaced almost every part on it with new (gaskets, water pump, spark plugs, etc.) since my engine was outside in the open (made replacing the spark plugs a breeze! :grin2:). Unfortunately, I got the wrong style of timing belt tensioner (98 vs earlier version), so I used the JDM's tensioner. That tensioner and my thermostat gave out last week, so I replaced the tensioner and will replace the thermostat soon. Otherwise, my engine is running great!
 
1 - 17 of 17 Posts
About this Discussion
16 Replies
7 Participants
ND Resident
Subaru Outback Forums
Welcome to the Subaru Outback Owners Forum, we have tons of information about your Subaru Outback, from a Subaru Outback Wiki to customer reviews.
Full Forum Listing
Top