Knock Knock!

mistersnowman97

mistersnowman97

New member
Hey guys,
just drove about 200 miles to tahoe. 4r ran great. But when I got up to the house, I noticed that there was a slight knocking that increased in speed as engine RPM goes up. The kocking isn't loud or feelable. Rather, it's more of a ticking or tapping. It just concerns me considering it was a semi-long trip climbing up in elevation at high rpm for about an hour. What does it sound like to you? I would like to hope it's not a rod... I'd like to think it's an injector..
 
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In my experience, an injector is more of a click sound. A more pronounced tick could be an exhaust leak. A knock is a deeper sound, with a little more reverb, and you'll definitely feel it if you put a screwdriver or something else against the block outside the knocking cylinder.

If it makes the noise at idle, see if you can track it down. If you drive it and it gets worse fast, park it before it blows up. The last time I tried to limp a knocking motor to the mechanic I ended up blowing a hole in the block.
 
Turn up the stereo and ignore it until you get back to town or it gets worse, would be my advice. If you feel like finding a mechanic, they might be able to listen around with their stethoscope and narrow it down for you, but what you're describing doesn't sound like a knock. I think you're good.
 
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That's really muffled, hard to hear anything at all. It'll help if you take your video from under the hood. You can rev it with the throttle itself, on the side of the throttle body.
 
With the tone of the muffled noise I'm thinking it's a little more severe than what you're hoping for.

As KidV said though, lift the hood and get a better video.
 
Yeah, try recording from in the engine compartment. My motor has had the valve tick-tick-tick for a while, but I'm building another motor, so I just ignore it. Yours sounds more of a knocking sound. Give us a better recording.
 
My 4runner has ticking but what I am hearing in your video is not what mine sounds like (of course I am thinking that my motor is running perfectly normal...) so what I would do is...

1. Drain the oil. Filter the draining oil through a paper cup or small screen to make sure there is no metal shavings in it. If no shavings then fill it with fresh new oil. (I assume you oil pressure is good??). If you feel brave try a heavier weight oil like a 10w-40 or 20w-50 and see if it stops.

2. If what above yields nothing than get that stethoscope out and start hunting for the noise.

3. If you have friends that happen to be Toyota mechanics you could take it do em and maybe get a free diagnostic??


That last one was far fetched but hey you never know :thumb:

Hope this helps and good luck
 
I luckily haven't had the chance to try this but have read this a couple times. A quick easy way to check if a rod bearing going is by pulling plug wires one at a time. If the knock gets considerably quieter on one cylinder then you probably have a bad rod bearing. By taking away the combustion pressure the noise should be reduced. If it doesn't change then it could be a main or something in the valvetrain.
 
Uggg, I was hoping it was just going to be lifter tick, which I hear at times in that video when you aren't tweaking the throttle. At the same rpm, my lifter tick is much worse when going up and over Mt Rose/431, and limited or nonexistent when on flatland or coasting down the hill.

If it is a rod bearing, you want to take care of it before there is too much metal filings in the oil, and long before you're "spun a bearing" and really messed things up.
 
I have to ask:
I know this probably sounds absolutely ridiculous, but bear with me and remember I am a clueless idiot.
Would keeping the spark plug wire of which is the culprit unhooked ease the engine at all and thus expand the life before the engine dies? Or is that the stupidest thing you've ever heard? I'm out of options and money.

BTW:
I have an idea of what could've caused this thing to go bad, so tell me what you think:
So right before I left, I did an oil change. When I went to the auto parts store to get oil, I grabbed 10-40. The guy at the counter ASSURED me that I should be using 10-30 for my vehicle. He practically wouldn't let me out the door unless I got the 10-30. So I figured "how big of a difference could it make to the engine for 5000 miles?". I did some reading to discover a less heavy oil can cause bad rod bearings... Does that sound right? And if so, should I go down there and give the manager a piece of my mind?
 
First, verify it's a rod knock. You can pull the oil pan and wiggle the connecting rods. If one of them wiggles a LOT then it's a rod knock. It could be a wrist pin too and to determine that you'll have to pull the rod bearing cap to be able to wiggle the rods. Make sure you label everything and put it back in the same place if you choose to do that.

If you already have a rod knock then unplugging the spark plug/fuel injector MAY prolong some engine life but you're still asking for trouble. Your best bet, grab a rebuild kit from engnbldr.com for a few hundred bucks and rebuild the engine. IF you caught the noise early enough there may not be any damage to the crank, rod or block. But if you keep driving on it then you WILL destroy something and it will cost you more money to fix.

As for the oil weight, I have never heard of that. If for some reason that was the cause then your engine was already going to die very soon.
 
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The difference between 10w30 and 10w40 is negligible, whatever happened to your motor was going to happen anyway.

If it is a bottom end knock, you could conceivably drop the front diff, drop the oil pan, and replace the offending bearing with the motor still in the truck. I wouldn't though, because once one bearing goes it's likely the others aren't far behind. You could buy a used engine and slap it in there and that might be marginally easier, but you'll spend less on a rebuild kit and learn more about your motor in the process. When you're done you'll have a motor with zero miles on it that you can trust for the next 10 years, as opposed to a junkyard motor with an unknown history.
 
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