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Subaru Forester Engine problems



  • kdshapirokdshapiro Posts: 5,751
    This repeatable problem is the easiest one for the dealer to diagnose. Take the car back to the dealer, leave it overnight and let the dealer fix the problem. Why have you not done that?

    What are the "many" problems you are experiencing? Is the dealer not willing to fix the car?
  • paisanpaisan Posts: 21,181
    Sounds like it could be a timing issue. Perhaps the belt is stretching when warm to the correct spot?

    Motorsports and Modifications Host
  • I've got a used 2002 Subaru Forester with about 57K (only about 3K of which are mine). It ran fine when we bought it, but several weeks later it developed a sporadic problem with engine hesitation and misfires. It's gotten progressively worse since then, and about a week ago the CEL came on for a bit and then went off again.

    My mechanic changed the plugs, wires, and air filter (all of which had to be done anyway), but that didn't fix the problem. He also checked the intakes and the fuel pressure, which seems normal, and then he tried a new coil pack. That didn't make a difference either. The reader isn't giving him any codes, except an error message he can't identify, and he thinks the problem is in the main computer. Any thoughts before I take it to the dealer?
  • ateixeiraateixeira Posts: 72,587
    It does sound like your mechanic is checking the right things, in fact I would have done the same thing, in that specific order.

    I'm puzzled that he can't read the codes, though? :confuse:
  • johnvjohnv Posts: 40
    After some more driving I've conclusively seen this happen. I was able to reproduce it a couple of times with the following scenario: driving on a flat road, accelerate away from a stop up into 3rd gear, push in the clutch fully and coast w/o brake. As soon as I push in the clutch, the RPMs drop to 1k and then after a second they slowly rise to ~2k over ~3 seconds. Then it falls back to 1k and the pattern seems to repeat (until I have to brake for the next stop sign).

    It doesn't seem to do this at a full stop or on a slight uphill grade and it doesn't happen every time regardless. Today the engine was pretty cool: ~60F out + ~10min drive + ~20min park + ~5min drive.

    It must the computer telling the throttle to do something -- keep the catalytic hot?
  • p0926p0926 Posts: 4,423
    The only time the engine should be idling fast is when it's still cold (or thinks it is). Where's the needle on the temp gauge when this happens?

    As long as the clutch is fully depressed, it doesn't matter whether you're completely stopped or coasting at 80 mph, the engine should be at idle speed (750 rpm).

  • frstr08frstr08 Posts: 2
    I have the exact problem with a 98 Forester S AT with 102k miles. I took my car to the dealer the first time the CEL came on and they diagnosed the problem as Cyl 1 misfire and replaced the spark plugs. The car was fine for a few days and then the problem came back at a stop light. I am able to easily replicate the problem by getting the engine warm and then stopping - like you would at a stop light. The hesitation is so bad that the car shakes.

    I have seen in other forums that the problem is with the ECM. Did any of you experiencing these problems arrive at the same conclusion? I would appreciate an update if anyone has found a resolution to this - will save me more costly dealership visits.
  • ateixeiraateixeira Posts: 72,587
    If you've only done the plugs so far, I would change the plug wires, too, which are usually a 60k miles item, and then the ignition coil (about $80 at a wholesaler).

    Either of those could be causing the misfire.
  • frstr08frstr08 Posts: 2
    I took the Car to Autozone yesterday to scan codes and got the same code as before P0301. Also this morning as I was driving in stop and go traffic, I got the same hesitation and the CEL came on. I will take the car back to dealer this week and have the above items replaced.
  • bsvollerbsvoller Posts: 528
    Well, I've been away a long, long while, but life is good with us. We still own the 01 Forester S+ that brought us to these fine forums, and replaced our 03 MPV with an 05 Outback XT last fall.

    Pleased to see so many old posters still haunting these parts: subearu, juice, paisan and the rest.

    I trust the recent past has been good to all of you.

    In addition to wanting to reconnect, we unfortunately have need for your advice. The Forester has developed a CEL that appears to be related to outside temperature. Drive more than a few miles with the outside temps below 40 or so, and the light comes on. A few days above 45 and it goes out again.

    I had the code pulled, and it was a P0128 - "Engine coolant temperature sensor out of range low."

    The dashboard engine temp gauge does indeed look to run a little on the low side, but it's hard to tell.

    What does that sound like to you guys? Thermostat? I'm told those "never go out".

    We had a fender bender last summer, so that everything from the fan belts forward is new. We're coming up on 8 years of ownership, and have enjoyed 78k otherwise trouble-free miles.

    Thanks in advance,

  • paisanpaisan Posts: 21,181
    Sounds like the Coolant Temp Sensor is bad. That's not the T-stat, it's an electronic sensor that tells the ECU what temp the car is running at so it can compensate for it with the fuel mixture.

  • My 2006 Forester stopped a week ago. After it was towed to Subaru I was informed that the reason the engine clanged to a stop is that there was carbon buildup in the engine. While I do have 67,000 miles on this less than 3 year old car I have also had four other Subs and have never had a major problem. Sommechanics I have talked to said this "carbon" explanation sounds bogus. Any suggestions on the issue and also how to deal with Subaru?
  • aathertonaatherton Posts: 617
    A friend's Element began to run poorly and suffered a drop in mpg at 30K and continued to 60K when it got so bad she took it the dealer. It was diagnosed with carbon build up on the valves. They offered a chemical treatment, very costly but cheaper than a mechanical repair. The Element ran better for awhile but then the problems appeared again. By then she had given it to her daughter and I don't know what happened to it.
    You say your Forester "clanged" to a stop, and titled your post with "seizure". That sounds like mechanical failure, not carbon build up.
  • paisanpaisan Posts: 21,181
    Yeah sounds like a rod or timing belt issue.

  • dengosadengosa Posts: 4
    I need your help please.
    I purchased a 99 Forester last September. Immediately I notice a oil leak. I replaced a head gasket.
    I took the car to multiple repair shops to get few opinions but the guy who did head gasket did not think there was anything wrong with the engine. He did a test on compression rings and he said they were fine.
    But now, it is very obvious that the engine is burning oil.
    When I start the car, there is ridiculous amount of smoke comes out. It stays smoking for about 5minutes or so and then it stops.
    I have read other discussions similar problem.
    I came to a conclusion that doing the valve job is the best solution for me.
    If anybody has advise for me, I would really appreciate it.
  • kurtamaxxxguykurtamaxxxguy Posts: 1,714
    It could be valve seals are leaking and allowing oil into intake manifold.
    Compression test would not find leaking valve seals.

    I had similar problems with two other cars.

    Also, one of the "high mileage" oil additives could help for the short term.
  • dengosadengosa Posts: 4
    So, basically, I need to have "volve job: done, right??

    How much does that cost usually???

    And I read on the yahoo that not all mechanic would do this kind of job.
    so for me to find the "right " repairman, what are the things I need to ask???
  • dengosadengosa Posts: 4
    I bought 99 Subaru Forester last year and now it is burning oil.
    well, so I was told.

    What can I do? Somepople say I need "Valve job" done. Some people say it wont fix the rpoblem, or they can not tell what it is that causes..

    Do I really need to look into replacing the motor???

    Please help.
  • kurtamaxxxguykurtamaxxxguy Posts: 1,714
    I'll try to be clearer about the potential problem....if any other Subaru crew folks wish to correct me please do so. :confuse:

    Short of holed pistons or cylinder walls :sick: there are only two ways Oil can get into the combustion chamber: from the bottom (past the piston rings), or from the top (from the valve/camshaft area).

    The compression test you had suggests the piston rings are ok. This suggests oil's getting into combustion chamber from valve/camshaft (valve block) area.

    Valve rockers, valve stems, and camshafts are lubed by engine oil. The only "passages" between those parts, and the valve surfaces doing the actual combustion chamber sealing, are drilled passages in the valve block. Seals sitting at the top (camshaft side) of the passages "wipe" oil off the valve stems and keep it from leaking into the cylinders.

    If those seals go bad, then vacuum in either exhaust or intake manifolds will pull oil from camshaft area into cylinders where it gets burned.

    Two general rules: If it smokes when you are accelerating, the intake valve seals may be bad. If it smokes when you are deaccelerating, the exhaust valve seals may be bad.
  • dengosadengosa Posts: 4
    Thank you for your response.
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