Loud Engine Rattle all of a Sudden

I have a loud engine rattle like there’s a golf ball bouncing around in the engine. So far the mechanics have no idea where the knocking is coming from. Here’s a video of the sound at idle. If you attempt to drive (or rev above 1500rpm) the sound becomes very loud and is then obviously undrivable.

It’s a 1999 Volvo V70, 2.4L, non-turbo, automatic
It has 260,000km or 162,000mi

Listen for the fuel injectors and the lifters. Under that there is a low, steady Knock. There is also a louder bang that is irregular. It sounds like I’m hitting the camera or the car but it comes from within the engine! First it’s irregular then catches up with the engine speed. Any thoughts on what those noises might be?

I was just beginning a road trip and all the fluids were checked.
Engine has appeared to be fine for years.
I pretty much only use Shell silver grade gas.
I had filled up the tank 100 km prior.
I had just changed the oil and filter 200km prior.
Symptoms appeared as I was pulling on to the highway for the first time that day.

As I accelerated on to the on ramp (with four passengers) the oil pressure light came on.
5km after that I thought I heard a low oil ticking so I pulled over to check and as I did, the engine really started knocking and whining.
Checked the oil and it was full and later I found out there was pressure. Coolant was okay too.
Turned the car on and oil pressure light never came back on.
No check engine light.
As I tried to get off the highway the knocking was so bad I could barely drive it. Probably should have left it. Got off the highway and called a tow truck.

The mechanic has drained the oil and found metal filings. He checked the timing belt and it is fine and hasn’t slipped. No idea yet where the sound is coming from.

I’m hoping to find a similar experience to help me determine (where the noise is coming from and) if I need a new engine.

You need a new engine. You drove the car down the highway with the oil pressure light on, the car then developed engine noise including ticking and now knocking, and the mechanic has now found metal in your oil. Oil level is irrelevant to the light, so the fact that the level was fine doesn’t mean anything. You said you later found that it had oil pressure, but a) you didn’t say much about that and b) finding it later doesn’t mean that you had it while the light was on. When the oil light goes on you pull over then and there and cross your fingers that it isn’t dead already.

You YouTube video didn’t show up btw.

I agree with cig above, except that I think the engine was toast before the light came on. But had you stopped, there would have been one shot in the dark that might have saved it and that is to replace the oil filter. It is possible, remotely possible that you have a defective oil filter, but it is far more likely that the engine was going to go out on you then and there wasn’t anything you could do about it.

BTW, the knock you hear is the sound of a spun bearing. The bearing was probably already worn down and it could have been worn to the point that it caused the oil pressure to drop so low. The it finally spun.

The technical term for the condition of your engine is “busticated”.

The question now is not where is the noise coming from, but how much will it cost to replace the engine. Stop spending time and money trying to determine the cause of failure.

Driving 5km with the oil light on is 4.9km too far. At the time the light came on the oil pressure in the engine was below the minimum required for adequate lubrication and engine damage started immediately, as evidenced by the metal debris in the oil.

Get prices for the installation of a rebuilt or god used engine, and be sure that includes new oil cooler lines and a radiator, as these items will be contaminated with the metal filings from your motor oil and will quickly damage your replacement engine.

So far the mechanics have no idea where the knocking is coming from

Actually if they didn’t know that noise you need new mechanics. I think they just didn’t want to be the ones to give you the bad news.

im having an identical problem…

I have a 2003 mazda 3, 1.6 z6, with 93000 miles in it.

For a while it has the codes p0012 and p0031.

The other day after some revving on the highway i noticed some loss of power, then suddenly there starts a loud clacking/clicking noise.
Stalls when cold and the noise gets worse as the car warms up. It dosnt go away while in park.
Also, sometimes, only between 1000 and 2500 RPM it for the most part goes away.

is it worth opening up the engine or adding something to the oil? what would be rattling?

thanks for everything!

Take it to a shop and have the P0012 investigated. This is a camshaft position error and could lead to the wonky oxygen measurement malfunction code P0031.

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what about the rattling? the oil was low

I’d guess the rattling is coming from your timing chain. Bad tensioner or failing guides.

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the thing is that it sounds like a jack hammer

how do i upload a video?

It’s possible a knock from the crankshaft position error is bad enough to make that sound. The engine might also be damaged beyond repair. You won’t know until it is evaluated. Don’t try to tell them what’s wrong, just describe the symptoms. Do it tomorrow on the off chance the engine isn’t destroyed already.


the problem is that i wouldn’t drive it and i dont want it getting stuck at a mechanic if its not worth fixing. any recommendations of additives or parts to look at before i go that rout?

Huh? Have the car towed to a shop for a diagnosis and estimate for repair costs. If it’s truly not “worth fixing” then you have nothing to lose by driving it home. The engine will make a lot of noise, but as long as the oil is full, it will probably get you home.

Also keep in mind that “worth fixing” doesn’t necessarily mean that the repair costs are less than the Blue Book value of your car–just that doing the repairs is cheaper than the alternative (i.e. buying a different used car that runs). I would say that the cheapest that you can buy a different used car and do the necessary repairs and maintenance to make it reliable is $2k, so I would be willing to spend that much to fix a car that I already own, even if it’s worth less than that. Of course, if the car has rust or body damage, then I wouldn’t put anything more expensive than a battery, tires, or fluid changes into it.