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Rod Knock 2004 2.5 Forester


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2004 Forester 2.5 non turbo 201,000 miles.  It has what sounds like a rod knock, not real loud and it's been there for a couple thousand miles and hasn't gotten any worse.  It's been there since I had the car, at first I thought it was just a noisy lifter.  Can only hear it when out of gear and rev it a little or when neither accelerating or decelerating.  How hard is it to replace the rod bearings without pulling the motor?  While I'm at it I'll also do the head gaskets.  My skill level is a few notches down from a mechanic but above a shade tree mechanic.  I have rebuilt a V8 by myself with good success.  And while it's that far apart should I do the rings also?  I'm wondering if there is enough room in there to hone the bores?  Or just pull the motor and rebuild the whole thing?  Or get a low mileage motor from pull-a-part?  I know right now there is only 1 2004ish forester there, anyone know what other years will swap in with minimal effort?  Or I could just drive it and if it doesn't get worse, keep driving it.

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These engines you cannot acces the rod bearings unless you split the case halves.  Cannot be done in car.

 

These engines don't have (lifters) the rockers ride directly on the cams, and they are manually adjustable for clearance.  no hydraulics.

Honestly unless you want to throw money at it, I'd keep driving until it makes some worse signal of what the problem is.

 

compatible engines can be found in 2000-2004 outbacks and 99-2005 Foresters and Imprezas w/2.5 

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Thank you both.  I think I'll take both bits of advice and keep driving it and try a little heavier oil, I think I put in something pretty lightweight.  This last arctic blast of cold weather it only got down to 18F here and this weekend highs in the 60's!   And a double thanks for the little rundown of the way the engine is built, although something just hit me, if it's not hydraulic why does it tap when first started then quickly it goes away?  Sure sounds like hydraulic lifters, in fact sometimes one of them taps a little longer, maybe for a minute til it stops.

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All of the SOHC 2.5 engines are solid lash adjuster.  no hydraulics.  guarantee it.  But the valves can still clatter a bit just from being dry where the rocker rides the valve stem.

other  possibilities are Piston slap?  or maybe a tad bit of rod rattle until oil gets to the ends of the crank?

 

 

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My 2003 Forester XS with 225K miles has a bit of tap/ light knock when the engine is warm that I only hear under load/ acceleration. When starting up it has quite a bit of clatter which I assume is piston slap. It's been there since I bought it in October, or at least I noticed it since I changed the oil right after buying it. I don't remember it when we test droive it ewhich makes me think there might have been some pretty thick oil in there.

 

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Unless design has changed in the EJ25 block, you can remove rods without splitting the case. Heads and sump needs to be removed. A pita but doable. 

Main bearings require the block to be split ;)

New rings while you’re there and you’re good to go. 

Cheers 

Bennie

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timing belt tenisoner uh, 'knock-mimic' wouldn't change with a change in oil viscosity. And, rod knock almost invariable gets worse/more aggressive-sounding with rpm increase. Most folks say piston slap reduces as engine temp gets to operating temp. It also would respond to a oil vis. change I'd think. Piston slap and rod knock would probably both be found in a used oil analysis from Blackstone labs as they increase metals.

Tensiioner knock kinda comes and goes and can even quiet-down at some rpms.

 

there is a youtube video showing tensioner knock.

 

 

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13 hours ago, el_freddo said:

Unless design has changed in the EJ25 block, you can remove rods without splitting the case. Heads and sump needs to be removed. A pita but doable. 

 

I don't think it's really doable.  Not while it's in the car.      

There is NO WAY to reach the #1 rod nuts.  The internal coolant crossover Is in the way.    How do you get to the upper rod nuts and the #1 nuts?  

And you wouldn't want to change rod bearings without polishing the journals first.  Doesn't seem like a practical solution.

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Timing tensioner was replaced along with the rest of the timing belt parts.  Same sound before and after.  Maybe I'll dump some thick crap like Lucas in it and see how it sounds.  It's not very loud now, I'll see what happens.  Thanks for all the ideas.

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5 hours ago, FerGloyale said:

I don't think it's really doable.  Not while it's in the car.      

There is NO WAY to reach the #1 rod nuts.  The internal coolant crossover Is in the way.    How do you get to the upper rod nuts and the #1 nuts?  

And you wouldn't want to change rod bearings without polishing the journals first.  Doesn't seem like a practical solution.

Why would you be doing ANY work in the car? That’s just nasty and seriously painful!

Maybe you’re right about the journal passages etc, it was ages ago we pulled an engine down just short of splitting the block in this fashion.

@Souperoo - was the tensioner a genuine item or aftermarket?  We had an aftermarket one go bad within 10k km.  Replaced it with a good used genuine item and it’s gone the whole distance of the timing belt change interval without issue. 

Cheers 

Bennie

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On 2/1/2019 at 11:14 AM, Souperoo said:

2004 Forester 2.5 non turbo 201,000 miles.............  How hard is it to replace the rod bearings without pulling the motor?  While I'm at it I'll also do the head gaskets.  My skill level is a few notches down from a mechanic but above a shade tree mechanic.  I have rebuilt a V8 by myself with good success.  And while it's that far apart should I do the rings also?  I'm wondering if there is enough room in there to hone the bores?  Or just pull the motor and rebuild the whole thing?  

In response to el_freddo 

Yeah I don't usually ever do any engine work in the car.

I was just thinking from the perspective of his original question.  What he was asking to do was not doable.

 

2 hours ago, el_freddo said:

Why would you be doing ANY work in the car? That’s just nasty and seriously painful!



2 hours ago, el_freddo said:

 

Edited by FerGloyale
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I dumped some STP in it and it got quieter but still there.  The startup noise that sounds just "like" lifters got really quiet, pretty much gone.

The knock that is in question does get louder with RPM if out of gear.  With a load on the motor it's very very difficult to hear while driving.

If I do pull the motor I'd probably fix it so I know what I have when I'm done instead of a junk yard motor.

The timing belt kit was Gates I think.

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On 2/1/2019 at 2:14 PM, Souperoo said:

  It has what sounds like a rod knock, not real loud and it's been there for a couple thousand miles and hasn't gotten any worse.  It's been there since I had the car, at first I thought it was just a noisy lifter. .

it's probably piston slap and benign.  ignore it.

perfectionists knurl the pistons to mitigate it if you want to pull it apart for something that will never cause issues. 

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3 minutes ago, idosubaru said:

it's probably piston slap and benign.  ignore it.

perfectionists knurl the pistons to mitigate it if you want to pull it apart for something that will never cause issues. 

Would piston slap go away under load?  And what is the chance of only 1 piston slapping? 

By the way, I don't know for sure what piston slap is, is it the skirt slapping on the cylinder wall?

Thanks

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4 minutes ago, 1 Lucky Texan said:

if you re-work this engine, you might consider an upgrade to the oil pump. particularly if that engine has a 7mm pump, get a 9. If you have a 9mm now, maybe consider a 10 or 11. at 228K miles, I'd bet some bearing clearances have opened a little.

Lucky, speaking of that, is the easiest way to check the oil pressure by removing the sender and installing a temporary gauge?

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I've never done it so, I'll say probably. There are also 'pancake or waffle' adapters that folks sometimes use under the oil filters - I think when they add gauges inside the car.

 

others will probably have better advice. I know the low pressure switch, for the warning light in the inst. cluster, only comes on at very low pressure - like 4 psi !

Edited by 1 Lucky Texan
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My 03' Baja is at 197K.  Has had the same noise he is describing for quite some time.  More noticeable at startup; less after the oil has gotten around.  I had been burning through more oil until I started using a Lucas additive or similar product (whatever is on sale).  Now, oil seems to stay around longer.

I know my mechanic won't dive into the block on my car.  He will do a swap but no work on the guts.  Feedback here suggests don't mess with the motor until it dies for good.  Are these blocks really hard to work on?

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