Knock at idle

[delta265]

My 99 with 195k on clock has had this problem for several thousand miles. It has progressively gotten louder so I took it to a good mechanic as I was stumped. Turns out to be a cracked flexplate. Not good, as they have to drop the trans to get to it.

Several other high mileage 4runners have also had this happen. Hope this helps...

 

[JEkema]

Hi all,
I have a 1999 4Runner LTD with 240K... In just the last few thousand miles, I've noticed a pretty nasty knocking noise that is coming from the engine...

It only occurs after a good half hour of driving, and then when the engine is at low RPMs - whether in gear or park/neutral. When I give a little gas, it seems to go away...

I took a video with my phone to demonstrate the noise - https://www.youtube.com/watch?v=GLOueKJT2Ao (for you impatient ones, skip to ~2:40 ) Does that sound like a flexplate?

I was told lifter tick at first, doesn't seem like that's the case. I've run some seafoam through the oil, but didn't seem to do anything... So now I am looking for ideas of what to try net, short of paying Toyota $400+ dollars to tear the engine down to see what's going on... hwell: Thicker oil maybe??

4Runner still runs like a champ, no loss of power or anything, just an annoying noise that scares me every time I hear it...

Also, I don't know if it's a coincidence, but I've noticed lately that it seems to take forever for my auto climate control to start pushing warm air (I'm in MI)... Used to get warm air within a few minutes of running, lately it's been 10-15 minutes before I get anything... maybe related, maybe not...?

 

[stir_fry_boy]

All of the 5VZ engines have an inherent knock to them. Mine has done it for 40k at least. I noticed it was worse when the belts were over tightened. I had my buddy look at it, a veteran Toyota tech, and he wasn't concerned at all. I have also had UOA done at 190k, no sign of any issues.

I use Prolong and synthetic oil and the knock is almost gone. Not getting worse. I'm not worried, I'll just keep driving it until something happens,

 

[JEkema]

[MENTION=48234]stir_fry_boy[/MENTION], does/did your knock sound like the one in my video? I also had a Toyota tech that I trust watch the video, and he thought it sounded like piston slap...
I'm basically also at the point where I'm just going to keep driving it until something happens, but if there is something cheap and simple that will fix it, I would love to hear about it!
Was thinking different oil, or thicker oil... if it takes 5w30, should I maybe try something thicker? What do all of ya'll run in yours?

 

[stir_fry_boy]

[MENTION=48234]stir_fry_boy[/MENTION], does/did your knock sound like the one in my video? I also had a Toyota tech that I trust watch the video, and he thought it sounded like piston slap...
I'm basically also at the point where I'm just going to keep driving it until something happens, but if there is something cheap and simple that will fix it, I would love to hear about it!
Was thinking different oil, or thicker oil... if it takes 5w20, should I maybe try 5w30 synthetic? What do all of ya'll run in yours?

I would make sure your belts are not too tight. I agree with just keep on driving it. Mine sounds similar but it is not always there. I was thinking about piston slap when I watched your video.

I use Prolong additive with Pennzoil Ultra Platinum 5W30 Synthetic (black bottle). The Prolong seemed to quiet the engine down quite a bit. You could try thicker oil, but if you live in a cold climate, it wouldn't be recommended.

You could consider sending the oil to Blackstone for analysis to make sure nothing serious is going on, that's relatively cheap.

 

[LookAtThatDog]

It doesn't sound that scary to me. Are you sure it's not something vibrating? The fact that it goes away when you rev is strange.

 

[JEkema]

Thanks for the replies, guys!

[MENTION=48234]stir_fry_boy[/MENTION], Thanks for the suggestions, I will have to try Prolong and full synthetic my next change... I also had heard some people swearing by Mystery Marvel Oil, so I bought a quart of that, but haven't tried it yet... Any experience with that?

I had not heard of Blackstone labs, I may have to try that... thanks for the reference!

Is switching to a thicker oil just potentially harder on the engine, or are there more repercussions? I'm in Michigan, which I'm pretty sure qualifies as a colder climate :tongue1: Sounds like you would suggest not bumping to anything higher than 5w30 then?

[MENTION=113822]LookAtThatDog[/MENTION], I can't rule something vibrating out at this point, and I guess that would make sense when it goes away with engine revving... but I don't think that matches up with no noise until after ~30 mins of driving (even when engine is idled down to the same RPMs)... I will have to get down under there a little closer and see if I can figure out better where the noise is coming from...

Any suggestions for pinpointing engine noises like that?

 

[JEkema]

Had my oil numbers mixed up, I edited the above posts... :ybrick:

 

[kolelt]

5vzfe are like known for weird tapping/knock soound. Mine has it sometimes. I know clean motor because I change oil every 3000k and when replacing valve cover seall it was clean there.

 

[stir_fry_boy]

Thanks for the replies, guys!

[MENTION=48234]stir_fry_boy[/MENTION], I also had heard some people swearing by Mystery Marvel Oil, so I bought a quart of that, but haven't tried it yet... Any experience with that?

I had not heard of Blackstone labs, I may have to try that... thanks for the reference!

Is switching to a thicker oil just potentially harder on the engine, or are there more repercussions? I'm in Michigan, which I'm pretty sure qualifies as a colder climate :tongue1: Sounds like you would suggest not bumping to anything higher than 5w30 then?

No experience with MMO. The key to oils is consistency. I would not run anything thicker than 5w30 where you are in MI.

Blackstone is awesome. Checking the oil for any abnormal high levels of certain metals can indicate abnormal wear. They write up a full report and send it to you.

 

[MATTPENN21]

Fix

I tried searching with no luck?
2002 sport, V6, 190k. When engine is warm, in gear at idle it makes a knocking sound. Put it in park or N and knocking goes away. Rev engine or while driving, no noise. Only in drive or reverse at idle when warm. Any suggestions?
Thanks

I have come across this issue more than a dozen times and fixed everyone. The problem comes from stress from the drive belts on the crankshaft bearings. You will need to replace the main bearings to correct this noise or simply leave it how it is and deal with the noise. if you replae the main bearings you need to go up for example- if stamped on the block is 2-2-2-2
then (starting from the front) you need to go with 4-3-2-2 main bearing size.
PM me if you have further questions.

 

[23ben32]

I have come across this issue more than a dozen times and fixed everyone. The problem comes from stress from the drive belts on the crankshaft bearings. You will need to replace the main bearings to correct this noise or simply leave it how it is and deal with the noise. if you replae the main bearings you need to go up for example- if stamped on the block is 2-2-2-2
then (starting from the front) you need to go with 4-3-2-2 main bearing size.
PM me if you have further questions.

Hey MATTPEN21, I am in North Austin - Georgetown(on the weekends). I would love to get a knowing ear's opinion on my problem. I hear about people taking their 4Runners all over the place, and getting conflicting answers. I can not afford to do this, but I'll spend the money I must, to make it right!

I have had my 2001 for only about two months, and I have noticed a knocking noise at idle, while in gear. It is very muted, and I can hear it best while in the car. I can feel it through the gear selector and transfer case selector, as well.

I am freaking out, because it seems like bad bearings. It only happens when warmed up, and only in gear. Sometimes, if it has started the knocking, I can take it out of gear, rev it, and get the knocking while it idles back down(just for a second).

Any direction, or even advice on a good shop to diagnose, would be appreciated. I usually do most work on my own cars, but am now in an apartment. I also have not done any internal motor work.

:help:

 

[danpba152]

2002 sport, V6, 190k. When engine is warm, in gear at idle it makes a knocking sound. Put it in park or N and knocking goes away. Rev engine or while driving, no noise. Only in drive or reverse at idle when warm. Any suggestions?
Thanks[/QUOTE]

Mine does this exact same thing and I am at 150K. Going to have it looked at this Saturday.

 

[23ben32]

I'll be interested to hear what is said about your 2002. I'm taking mine, a 2001 with 185k on the motor, in on Tuesday or Wednesday. I'll be sure to post the findings.

I'm glad to have found this resource!

 

[danpba152]

I will post my results Saturday after I get back from the shop.

 

[23ben32]

I just got the call from the repair shop. They say main and possibly rod bearings. Said mechanic put a stethoscope on it and definitely main, maybe rod bearings, as well.

They want to put a used motor, with 100,1000 miles in it, to the tune of $4500! They would do all the accessories /water pump/timing belt, and warranty for 90 days.

I'd love to find someone that could check on the bearings and replace, if possible. Everyone seems to think that's a fool's errand, though.

This is killing me!

I hope you have better luck.

 

[danpba152]

I wasn't able to bring mine in Saturday because I was sick. It will be looked at this Saturday. Will let you know what I am told.

 

[danpba152]

Found out my noise was coming from the crank shaft pulley. Replaced the pulley and had the belts loosened, they were tight from when I had the timing belt replaced. All seems good now.

 

[frodiesel]

Good read, going to order a crankshaft pulley.

 

[AntleredRuin]

Good read, going to order a crankshaft pulley.

Before you do this, remove the AC belt first. I'm having the same issue, but the noise is a bit more noticeable when the compressor is on. I removed the belt and dead silence. This pinpointed the AC being the culprit at least. My idler pulley has a bit of a click to it when free spinning (it should be dead silent). The idler pulley only costs about $20 vs a few hundred for the crankshaft pulley. Even if your compressor is shot, a reman can be had for around $100 from eBay with warranty.