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on the 98 plus cars it could be t-belt tensioner noise.

how many miles?

how long since the timing belt was done?

 

but if the people telling you this are competent, then it probably is.

but i would get a second opinion from a subaru guy before i spent a lot of money on a replacement engine.

Edited by johnceggleston
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on the 98 plus cars it could be t-belt tensioner noise.

how many miles?

how long since the timing belt was done?

 

but if the people telling you this are competent, then it probably is.

but i would get a second opinion from a subaru guy before i spent a lot of money on a replacement engine.

look for a spot inside the TB cover that is 'rubbed' from the loose belt.
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piston slap and timing belt tensioner can sound exactly like rod knock to anyone that isn't well versed in the differences on Subaru EJ engines, a mechanic could easily be mislead.  I got a Subaru from a mechanic with "rod knock' and it was merely piston slap.  i mean rod knock is certainly possible, plenty engines are run low on oil and get rod knock....but make sure it's not something simple.  piston slap is loud but meaningless and the car is fine for 100,000+ miles with it.....it doesn't even need repaired.  timing belt tensioners are $100.

Edited by grossgary
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won't hurt to check the timing belt...

 

When my sister brought it over it was knocking very loud. Parked it, and let it sit about a week, until I posted pics on here. Then It wasn't knocking at all, so I drove it around for about 15 min before the knocking came back.

 

About a week later we changed the oil adding a quart of power punch. I drove it around for about 30 min, the knocking was faint and only at high r.p.m.'s or when the engine was pulling a load. Sometimes when you let off the gas you would hear it, also.

 

no metal flake in the oil.

 

It sounds to me kinda like something is one of the cylinders. I've never heard a bad bearing, but I have heard the same sound in old tired engines.

Edited by Godsmulligan
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this is good news - rod knock generally does not go away, not in subaru's anyway.  once it's there it usually only gets worse.

 

this sounds like symptoms of a failing timing belt tensioner - it'll vary by load, temperatures, etc as it's getting weak and tired. 

 

on older models you can remove the timing belt cover to check - it's 3 minutes and three 10mm bolts.  i think on 99's they went to a larger cover that's integrated and you can't just remove the drivers side any more though....

on the 99's you can remove the serpentine belts, crank pulley, then the timing cover and simply run the vehicle with the cover off for a minute and none of the serpentine belts hooked up.

or reassemble the motor without the cover if you're uncomfortable or don't know how to do the above.

 

once you can see the tensioner, run the engine and you'll see it "flopping" around, it'll be vibrating and when knocking it'll be rapping loudly against the metal around it.

 

ebay kits offer complete timing belt, pulleys, and tensioner for $160 - $200. 

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You have to split the case to do any bearings on a Subaru engine.  

If the heads are off, you can pop out the pistons and remove the rod caps with an extension, through the opposite cylinder.

 

So technically you could change just rod bearings without splitting case, but I wouldn't recommend it. You can't access the crank pins to measure and clean.

 

Main bearings obviously require splitting the case

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If the heads are off, you can pop out the pistons and remove the rod caps with an extension, through the opposite cylinder.

 

So technically you could change just rod bearings without splitting case, but I wouldn't recommend it. You can't access the crank pins to measure and clean.

 

Main bearings obviously require splitting the case

but could an engine be 'inspected' for bad rod bearing with just the pan off?

 

I think, similar to ivan's idea, an oil analysis could diagnose a bad bearing too.

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rod knock generally does not go away, not in subaru's anyway.
my 00 lego w/ 85k miles spun a rod bearing.  i didn't really hear it since my wife was driving it.
she did report that it was knocking and i did give it a short test drive with no knocking.
the next day it completely failed on the hiway.
 
my only guess is that the bearing was worn and started knocking.
it then rotated a little and found a place to rest where it did not knock.
then 150 miles later it spun and died on my wife 2.5 hours from home. crap.
just a guess.
 
 
but gary is right , it does not sound like rod knock.
 
read through the link and see if you can narrow it down.

do the test they recommend with the plug wires.

(i have been recommending this link since i found it in 05, soon after i boubht a 97obw with a bad ''wrist pin''.

it turned out to be piston slap. i drove it for 45k miles and sold it for more than i paid.)

 

http://remanufactured.com/Engine_Diagnosis_101.htm

 

good luck.

Edited by johnceggleston
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copy that JCE, i should be careful using "never" and "always". 

 

 

my 00 lego w/ 85k miles spun a rod bearing.  i didn't really hear it since my wife was driving it.
she did report that it was knocking and i did give it a short test drive with no knocking.
the next day it completely failed on the hiway.
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piston slap if was rod it whould not last that long time the oil light how many millaseconds it takes to go out will tell you haw bad it is I have 3 rod knocking cars here right now and its violent I can hear the piston hitting head wack wack whole car shakes and can barly move it pull dipstick is sparkly. Alo have a 2.2 that was ran outa oil and refilled and restarted knocks very bad till oil light gos out then trys to fix itself but to far gone same deal barly runs and shakes whole car very violent. I bet yours is just piston slap a rod does not get better as it warms up

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Eother way, if the rod bearing is shot, it would be more economical to source another block and use it as-is, as the bottom ends don't wear out until hundreds of thousands of miles. 

 

Rebuilding the block would only be necessary if you were building some sort of high performance hybrid with aftermarket parts.

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Sometimes the oil pumps will fail an internal seal, losing oil pressure. During routine maintenance, you take off the oil pump and loc-tite the screws on the back to prevent/fix this. Just an idea this may have caused your engine failure. not as common a failure, but easily preventable with front engine overhaul.

Edited by MilesFox
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Sometimes the oil pumps will fail an internal seal, losing oil pressure. During routine maintenance, you take off the oil pump and loc-tite the screws on the back to prevent/fix this. Just an idea this may have caused your engine failure. not as common a failure, but easily preventable with front engine overhaul.

 

Yup, most pumps I've pulled off have a loose screw or two.

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but could an engine be 'inspected' for bad rod bearing with just the pan off?I think, similar to ivan's idea, an oil analysis could diagnose a bad bearing too.

Nope. The heads would have to be off and the pistons pulled. Might as well split her at that point

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