The New York accent shined through over that rod knock 👍 best comparison video online. thank you!

@Motorcarnut

27 күн бұрын

Glad you liked it!

You forgot to rev the engine knock so we can hear the difference.

Thanks for the video!! My Honda B20 has some bottom end tapping when the coolant is warmed up enough for the idle rpm to drop lower but the oil and metal isn’t very warm yet, and I was 98% sure it was piston slap (fairly common on the B series engines) because its never complained about me wrapping it out to 7000+ rpm, and this confirmed that and put my rod knock fears aside. Thanks!

@Motorcarnut

3 ай бұрын

Thank you for the comment. Yep seems like that to me too from what you explained.

This is exactly right. I just built a 2008 2.5 SOHC engine using a good 2001 block and crank. Good used 2008 rods and new 2008 pistons. I put new rod bearings in but couldn’t get a good set of main bearings anywhere so I opted to use the old ones that were in very good shape. I plasti gauged all the bearings and they were all perfectly in spec. The wrist pins to small rod end were perfectly in spec. The new pistons had about 8 thou of piston to bore clearance which was a ways out of spec but I decided to give it a go since the ring end gap was good. The heads are rebuilt and surfaced. Anyway, what I’m getting at, is it had a small knock like the first example but not near as loud and it worried me but I know for sure it couldn’t have been rods because I went through all them. I know the pistons were sloppy so that’s gotta be what it is. Goes away when warm or when reved.

@Motorcarnut

3 ай бұрын

Yep, exactly right!

Picked up a rust-free 2006 Impreza 2.5i 6 months ago for my son. It had a rattle on start-up, and some noises, classic Subaru, they're all I drive. Now, he is gone all the time and I see and hear it infrequently. But when I heard it idle at times, I thought it sounded worse. I changed the oil, but no change in sound. I had access to the car just after Christmas and the loud tapping/knocking occurred in the following cycle: Distinct at idle, increased upon accellerating, then gone while cruising along. When letting off the gas to coast approaching a stop sign, the noise returns when it gets to 25 mph > idle. The local Subaru specialist had it today for some other things, and he checked the sound, confirmed no exhaust leaks, and suggested rod knock. When I drove it home, I wasn't sure if I'm now oversensitive or if the symptoms described were far more pronounced. Never had this with any of my Subaru's. Any opinions?

@Motorcarnut

4 ай бұрын

From what you’re describing it’s not really going away when fully hot so it’s probably a rod letting go. You can try to put some oil treatment like STP in there just to see if it gets more quiet,if it does then the rod bearings are failing.

@Tomas.X

4 ай бұрын

@@MotorcarnutThanks for responding. I like my Subaru specialist mechanic, but we seem to have communication issues. Long story short, this knocking sound was apparently "quite pronounced" at the shop yesterday (and when I drove home, he was right, it was much worse than when I drove it there the day before.) I changed the oil last night and ran a big magnet around, and there was some tiny metal bits, but nothing dramatic. The "communication issue" I referred to was a chat a couple months ago when he believed a coolant leak was my HG...but it was the radiator. It has not overheated at all. But he recommended yesterday new block and heads, citing "danger" the heads may have warped from overheating "at some point". I could order a long block...would save the machine work the shop would do...but it comes with a new timing belt kit, which means losing the money I just invested 24 hours ago. I should also note this guy lost his long-time machinist that did block/head surfaces...but he "could find someone" to do it. But again, he's rather hung up on the "get new heads" advice. So is there any reason to bit the bullet and just get a long block? (Maybe I could arrange a long block w/o a timing belt kit...but doubt that's possible because most engine shops pre-run the engine before shipping it out.) Thanks for the advice...dealt with so many thinigs but this (especially with a non-turbo) is all new to me.

@Motorcarnut

4 ай бұрын

@tomasx9027 If the car is worth it to you and makes sense money wise a long block would be the best bet, less labor to rebuild your old one and should come with a warranty. Timing kit you have just keep it as a spare.

Thank you for showing both! I don't have a Subaru but my Sebring is making a similar noise (210k miles) to the piston knock. Hopefully that's what it is but I guess I'll find out LOL

@Motorcarnut

4 ай бұрын

Good luck!

Thanks for the efforts

@Motorcarnut

2 ай бұрын

My pleasure, and much appreciated

excellent video

@Motorcarnut

4 ай бұрын

Thank you very much!

Good video. I just seized my 2008 Subaru Impreza 2.0 engine completely. The mechanic had just a quick look because it was not worth it to do a full inspection but he thought the crankshaft cracked. It made the knocking sound as well before it seized. It already used excessive amounts of oil for months. Fixing it would break the bank so I'll bring it to the scrapyard.

@Motorcarnut

4 ай бұрын

Thank you! Sorry to hear that, if the vehicle is worth fixing, i have videos on rebuilding or replacing engine.

Great video, my suggestion would have been to add the valve tick noise for the third option of what a lot of Subaru owners hear

@Motorcarnut

4 ай бұрын

I’ll make one of those when i get one in.

@Kragum24

15 күн бұрын

I have a 2023 Crosstrek with a 2.0 liter motor, with 20,000 miles on it and it runs like a top, and the motor is about as noisy as a top! Those 2.5 liter engines can start ticking and making other engine noises shortly after purchase, and most will eventually become noisy. If you want the little extra horsepower and torque that the 2.5 liter offers, you might have to tolerate some annoying engine noise(s) for the life of the vehicle. Not worth it! My 2.0 liter has 20,000 miles and is super quiet, even on start up. I'll take the smaller, quiet 2.0 liter motor, over the bigger, junky sounding 2.5 liter motor any day.

@Motorcarnut

12 күн бұрын

@Kragum24 yours will make noise soon too. They all do at some point.

Yep, I always have loved an engine that will blow up very quietly😆👌

@Motorcarnut

3 ай бұрын

Depends, engine knock, yes but piston slap could go on for years on Subarus with not problems.

i had this sound when knocking can be heard when accelerating especially at low rpm but not at idle. Any idea?

@Motorcarnut

6 ай бұрын

If it doesn't go away when hot, it's either a rod going or excessive piston slap.

Nice video ! Will Piston Slap / Rod Knock make your car shaking a bit? Are there more hints that can help distinguishing them?

@Motorcarnut

3 ай бұрын

Yes it will. Piston slap is twice as fast as rod knock

@hongccc

2 ай бұрын

​@@Motorcarnut You are so helpful! What do you think about this noise? Planning to do a full check later this year, and i hope this is not some serious problem kzread.infob-_rA-0jx3M

My Subaru sounds like the second one when it starts up and is very loud, however after it warms up it sounds pretty normal 95% reduction, I can hear a little when I give it higher Rpm’s but with windows up can’t hear a thing. Would this still be piston slap since it goes away when warm?

@Motorcarnut

5 ай бұрын

Yes it would

@captivabreed176

4 ай бұрын

It’s likely what your hearing is your valves ticking. This is also very common with Subarus

Bought a 2015 legacy 2.5i a little over a year ago. Bought it at 108000 now has 145000. Engine gets a little loud when cold starting. Michigan weather for reference. Obviously cars hate cold weather but hearing what a problematic boxer sounds like helps a lot. Now i know what to look for in case something is actually wrong. That being said, these engines are noisy for a 4 cylinder

@Motorcarnut

3 ай бұрын

Yes, they are. I don’t like it as a mechanic but had many over the years and were very reliable.

I have a knock on 3000rpm only sti 2004 with a lot of power loss but no knock whn idle any idea ?

@Motorcarnut

4 ай бұрын

Sounds like pistons are failing

Mine is odd its got a new rebuilt engine its quiet when cold then when it warms up it has a small knocking noise but only at idle if u give it any kind of throttle it goes quiet again

@Motorcarnut

5 ай бұрын

Normal

Alright now stuntman hold her to the boards and get to it! LOL

Is Rod knock present at start of a vehicle? Can the knock noise come and go? I have a knock that isn’t consistent and comes and goes away

@Motorcarnut

Ай бұрын

You have probably piston slap

If the knocking is quieter, is it not rod knock? I've had my engine go low on oil (dipstick completely dry) a few times. But it's fairly quiet and only occurs at around 1,500 RPM.

@Motorcarnut

4 ай бұрын

Unfortunately it can still be a rod knock just not the bad yet.

@shawntee1859

4 ай бұрын

It’s Definetly a big end gone (connecting rod bearing) engine is toast. Replace itl just get worse.

@Aashishkebab

4 ай бұрын

@@shawntee1859 fear-mongering for no reason. Chill out.

hey how are you, I have a big problem, I have a Subaru Forester 2009, I just changed the head gasket and put it back together everything, I know everything is connected but my car doesn't run, the car has a crank, but I listen the pistons hitting the heads, and I don't know waths is going on, can you help me whit this THANK YOU SO MUCH

@Motorcarnut

3 ай бұрын

Sounds like the valve timing is off. Their isn't any other way the pistons will hit the valves unless it is off.

I get a tick that I assumed was lifter issue , it occurs a low revs and hi revs any idea why there is a sweet spot where the sound goes away ...is the con rod bearing likely?

@Motorcarnut

Ай бұрын

That can be a collapsed lifter. Is there a misfire present?

@ziffification

Ай бұрын

@@Motorcarnut doesnt missfire

@Motorcarnut

Ай бұрын

Could be piston slap, connecting rod won’t go away

@ziffification

Ай бұрын

@@Motorcarnut I am going to get it into my garage and check/set the OHC lifter gap ...what does a collapsed lifter look like?

@Motorcarnut

Ай бұрын

@ziffification would have excessive valve lash between lifter and valve

There was a knocking on my hyundia tucson 2.0 petrol but after a few minutes it was gone but it sound like it was coming from the head of the engine must i worry about it?

@Motorcarnut

5 ай бұрын

Yes, it can also be from the timing chain hitting the oil squirter, not good

@gicugigel3790

3 ай бұрын

Thats piston slap, these are common on Hyundai's

@Motorcarnut

3 ай бұрын

@gicugigel3790 not really common on Hyundai

@gicugigel3790

3 ай бұрын

@@Motorcarnut from what i've seem, pretty common, both on diesels and gasoline engines. Their engines tend to develop piston slap or rod knock. My Hyundai engine had piston slap, replaced the engine and the new one also developed piston slap. I've seen theta 2 with piston slap and even V6. The guy from 1st comment, says his engine knocks and gets quiet when warm, thats piston slap 100%. Thats the way a piston slap acts, at least before gets worse over time and wont get quiet anymore.

@Motorcarnut

3 ай бұрын

True about the piston slap getting quiet when warms up but no so many Hyundais came my way yet with this particular problem.

If it was a rod knock would the Engine light be on? My engine light is not on and I’m up to date with oil changes. I’m just still having trouble hearing the difference between the two

@Motorcarnut

Ай бұрын

No it doesn’t have to be on. If the noise goes away when warm it’s piston slap if not it’s a rod knock.

my first car was burning oil and i had no idea, so one day my engine exploded on the highway, and it was very loud knocking sound. now 10 years later, im facing a problem with my hyundai kona 2020 burning oil, keep adding more every few days

@Motorcarnut

Ай бұрын

Those engines are under a recall for free replacement you may want to contact Hyundai

is piston slap not slapping when doing engine brake? mine when i step the gas its sounds knocking like in the video, but when i do engine brakes its gone (sorry for my bad english)

@Motorcarnut

3 ай бұрын

It's less when braking but still there, yes.

@eccentr3c.

3 ай бұрын

@@Motorcarnut ahh i see, thanks for the answer

@Motorcarnut

3 ай бұрын

No problem

When the knocking sound just appears in certain RPMs like 3.000 rpms . What could it be?

@Motorcarnut

6 ай бұрын

It's a rod knock, doesn't matter when you hear it most.

@GHOSTERING

5 ай бұрын

Some engine dont have rod knock on cold start or idle like STI engine or WRX engine, sometimes you start to hear it at 3k rpm en generaly it's a rod bearing that spun due to oil stagnation or over rev like when you do a pull and money shift. My 2019 WRX does not have any of this sound and i'm happy.

@Motorcarnut

5 ай бұрын

@GHOSTERING True, some are very quiet but sooner or later they will get a little noisy

thanks brother i thought it was knock 😂😫

@Motorcarnut

6 ай бұрын

No problem 👍 Glad it helped!

hi great video , piston slap is gradual or just suddenly starts one day ? thanks

@Motorcarnut

4 ай бұрын

Piston slap is gradual as it starts to wear.

Thank you so much for helping me distinguish what an engine knock sounds like - and what a Subaru engine sounds like hahaha.

@Motorcarnut

3 ай бұрын

Glad to help!

Does a quiet slight knock mean you need a new engine?

@Motorcarnut

6 ай бұрын

On a Subaru probably not

@GHOSTERING

5 ай бұрын

Depend, if you have rod knock but you stop the engine soon enough you can just rebuild the internal and the engine will be good for a long time, sometime the block have no damage and can be save. It just cost a rebuild wich is cheaper than buying a brand new engine.

Hi. If it’s a rod knock. How long do I have before engine is defective?

@Motorcarnut

4 ай бұрын

Immediately

@shottaafrif4213

4 ай бұрын

@@Motorcarnut the knock comes and go away. Sometimes I idle and I don’t hear it at all. At time at hear it. Also slight hesitation when starting. Thanks for your reply.

@Motorcarnut

4 ай бұрын

You can’t play around with engine knock it will destroy engine without any more warning signs

@maegantucker973

2 ай бұрын

Mine did that on my Corolla. I can’t drive my Corolla anymore. Lol.

@Motorcarnut

2 ай бұрын

@maegantucker973 nope

What’s worse to have. And is piston slap something you have to address right away.

@Motorcarnut

6 ай бұрын

Engine knock is much worse. Piston slap that goes away when vehicle is hot can last the lifetime of the vehicle. Piston slap that doesn't go away after warm should be addressed sooner than later.

I dont have a subaru anymore but i have an 02 accord im trying to flip, upon start it makes a knocking type sound but only on cold starts. After 10-30 secs it goes away and the car drive normally shifts smooth and makes no sound. Is it bc it’s basically oil starved on cold start and as oil circulates it goes away?

@Motorcarnut

5 ай бұрын

It very well can be. If you didn't already, try changing the oil and filter and using a oil additive like STP, should help.

@Andy3x

5 ай бұрын

@@Motorcarnut i did an oil change and the time it takes for the noise to go away is way shorter than before the oil change, im gonna try stp and see if it stops it completely

@Motorcarnut

5 ай бұрын

@Andy3x yes, it’s cheap and worth a shot.

Could I send you a video of my vehicle some how to see what it is I can’t tell

@Motorcarnut

4 ай бұрын

Yes, post it on your channel and let me know

Sounds be like that, but everything works normal, right?

@Motorcarnut

3 ай бұрын

Most of the time, yes

What’s an easy way to get rid of a engine rod knock?

@Motorcarnut

Күн бұрын

No easy way outside of rebuilding the engine.

I have a video on my page can you tell me if it’s a piston or rod knock

@Motorcarnut

2 ай бұрын

I just did. That definitely sounds like a rod knock. One thing you can do to rule out an accessory or pulley noise is to take off the serpentine belt and start it back up, if it sounds eacly the same its a rod knock and would have to be rebuilt or replaced.

Thats the subaru swag

@Motorcarnut

6 ай бұрын

Yep

Does a rod knock mean engine replacement ?

@Motorcarnut

Ай бұрын

Short answer, yes but also can be rebuilt

With rod knock, engine speed with changes the rate but not the intensity.

@Motorcarnut

7 ай бұрын

Depends on the severity of the knock.

I must have a bad ear on this stuff it sounds like my truck but my sound is constant and follows rpms i have a short clip on my channel

@Motorcarnut

Ай бұрын

I’ll give a listen when I’m on my desktop.

@wicked5312

Ай бұрын

@@Motorcarnut i'd appreciate that

Washing machine vs helicopter

@Motorcarnut

3 ай бұрын

I guess, lol

That’s garbage my 4.2l ford with 300k miles on it sounds quiet as a Prius compared to this thing. I’d be scared to drive that pos around the block both of them sound like the pistons are about to shatter from all the slack and vibrations. Really sounds more like a wrist pin knock instead of piston slap.

@Motorcarnut

5 ай бұрын

You never owned a Subaru.

Just happened to my car 10 days ago

@Motorcarnut

4 ай бұрын

Sorry to hear that, maybe it can be rebuilt or replaced?

@alihasan-dg7vz

4 ай бұрын

@@Motorcarnut I must change the engine or I will sell the car

@Motorcarnut

4 ай бұрын

@alihasan-dg7vz Yes, but first get a second opinion from someone local

Im definitely the second car 😢

@Motorcarnut

2 ай бұрын

??

What if the rod knock goes away?

@Motorcarnut

2 ай бұрын

You’re very lucky

@sporty1976s

2 ай бұрын

@@Motorcarnut I used the wooden dowl rod method to listen to the inside of the motor. And it was clattering loud. The tensioner pulley started making a noise and the power steering went out the ps pulley started screeching and the knock went away at the exact same time. I changed the tensioner pulley and power steering pump (I used the original pulley) and the vehicle runs great. So I'm actually thinking it was the ps pump that went out causing the pulley to screech and knock.

@Motorcarnut

2 ай бұрын

Great diagnosis! That was probably it!

Sounds like diesel clatter

@Motorcarnut

2 ай бұрын

Yes it does.

My car is doing this and just cut off ‘

@Motorcarnut

Ай бұрын

Have it checked out asap hopefully you didn’t blow the engine.

Makes me want to stay away from Subaru either way

@Motorcarnut

6 ай бұрын

That’s understandable, but they still make great vehicles. The design of these engines is what makes them more noisy than the competition. But the newer ones are more refined.

@EternalSilence4ever

4 ай бұрын

There's nothing wrong with a Subaru.

@Motorcarnut

3 ай бұрын

True

@melissasmess2773

2 күн бұрын

The newer F engines leak oil and have TCV failure.