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engine knock on 1996 Subaru legacy


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I took my car driving after getting the valves replaced.then the oil sign popped up then the engine started making a weird noise.I pulled over off the free way then the engine died.Overtime the hazards and lights on the dash started dimming then eventually they died.No power what so ever would come from the car and when i started the car it gave me a clicking sound like a dead battery.I checked the oil and it was low but i Did put some in.Yesterday,I jumped my car and it turned on how ever there is a loud knocking noise when Ever i hit the gas but then after awhile the car dies.No check engine light.if it was a knock in the engine wouldn't that go off?The car is full of oil now yet the oil light is still on.What could this knocking sound be?I did read online that the alternator going bad could cause a knock or could it be that the engine is now messed up do to lack of oil?any ideas?

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check engine lights are worthless for internal issues. It just indicates air/fuel sensor stuff.

 

Maybe get a video of the noise so it can be identified?

 

When these engines get low on oil, they do die. Possibly a faulty oil pump, but they don't go out that often. I had a 91 legacy that had thrown a rod right through the top of the block. I sourced a used engine and put it in - bout $200. all told to swap it in.

 

Good news is, even if this engine is toast, you live in an area where you should be able to source a good used engine cheap. Colorado has lots of Subarus. Takes an afternoon to swap an engine in these cars. Figure a full day if it's your first time. But they are easy to work on.

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Why were the valves replaced, what happened?

 

How low was it?

How much did you add and how far up the dipstick was it after you added that amount?

 

Knocking from front of engine, rear, or left/right?

 

You had the valves replaced?  That's a substantial job - how many miles have you driven since that job was done?

 

Front of engine would be timing tensioner (drivers side front)

Rear of engine would be flexplate cover

Sides of engine would be valve train related


Other may be bearing failure

 

Or possibly a job related issue...

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@zacharyg Is the alternator actually charging? On some cars if the alt. dies, you'll get dash lights. Did you check that the belt is still there? To check the timing tensioner, you need to remove the serpentine belts, crank pulley, and both covers. Water pump is driven from timing belt so car can be started with acc. belts off. Watch the tensioner for the timing belt. If it's jumping or moving erratically while idling or revving slightly, it's bad. Several how-to videos on You Tube. Very easy fix and can cause a knocking sound that can fool you into thinking it's a main bearing or something.

 

 

@Grossgary, can you elaborate on the flexplate cover sound and what causes it? I've been getting an odd *zing* sound like something briefly bumping the teeth, and a slight random knock that I don't think is internal from the same area. Might help the topic starter too otherwise PM.

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The light is for oil PRESSURE, not oil level.

That light comes on because there is no oil pressure. Your bearings have been run without oil and are now damaged. No amount of new oil is going to fix them.

You need a new short block at this point.

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I replaced the two exhaust valves on Cyl 3. It was showing a misfire (p0303). It had about 60psi on that cylinder, the rest showed around 120. A leakdown showed that it was leaking out the exhaust valves. I pulled the head with the engine in the car, so the flywheel cover wasn't touched. It has the old style stick tensioner on it and it was in great shape (I've only ever seen the newer style tensioner cause a knock sound). After I burped the radiator I drove it about 10 miles and reset the cel (had 10 codes stored) and drove it some more. The CEL didn't come back on, and I did notice a hard crank, but nothing seemed to be dimming and my meter was at work so I assumed it was a battery on its way out.

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Sounds like my Ej25D with rod knock.. in my case the oil pressure light did not come on.. not sure if the pump gave up or it sucked up air.. by the time the light comes on it's pretty much at 0 PSI..

 

 

looking forward to the teardown to see how bad things got.. going to put a EJ22 in but prices are all over the place.. what idiot would pay $800 for a EJ22 with 122K on it???

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You may have experienced the rare occasion, but known to happen, of an oil pump failure due to the screwd backing out and compromising the inner seal. Please remove the oil pump and inspect for this.

 

This is also preventable any thie the oil pump is removed, you can loc-tite- the screws to prevent this.

 

This is a reare occirrence, but it does happen, and it really is the only thing that can happen detrimentally to the bottom end.

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