Toyota 2L-T engine tapping sound (1 Viewer)

[matus]

Hi to all,

I have noticed a tapping sound on my LC70 with 2.4 diesel engine. The weird thing is that the sound is not present right after start. It takes a while until it starts tapping. I would like to know if anyone has experienced such issue.
My plan is to check valves, drain oil and remove oil pan and check bearings. Last step would probably be to check compression if I wont find anything suspicious.

here is a link for a video where the sound starts approx in the middle of the video ( 20 sec):


Thank you for comments.

 

[Felde]

Hi
I'd say that's knocking / pinging due to wrong engine timing.
Check timing as per workshop manual.
Check injectors.
Don't touch the oil / oilpan.
Cheers Ralf

 

[Eurasiaoverland]

100% agree with Ralph here. Does it go away when the engine is up to temperature?

 

[matus]

Hi,

I did not check it when it is warmed up as I was afraid if that sound and did not want to make further damage to the engine. I will check the timing and oil needs to be changed anyway.

The only thing that I find strange is that this sound is not there right after start but it takes a while until it starts to tap like hammer on steel. Would not timing affect it right away after start?


I will check it next week when I investigate it further and update you on the status.

Thank you

 

[matus]

Hi to all ,
I have checked the timing belt and it is spot on marks see pictures.

Let me know your thoughts.. My plan is to change oil.. and check valve springs...

thank you

 

[Eurasiaoverland]

The timing check is not done with the belt. Do you have a service manual for the engine?

First check, is the line on the front mounting flange of the injection pump lined up with the other half of the line on the timing case?

Does the injection pump have a cold start device? Post some pictures of the pump.

Also, when did the noise start? Did the weather suddenly get very cold? Did you put some bad fuel in?

It's hard to tell from the video, but the noise just sounds like normal diesel knock to me.

If you hear a metallic tapping noise you can buy or improvise a stethoscope (can be just a big screwdriver held to your ear) and try to trace the noise.

 

[matus]

Hello ,.

I have a service manual for 2LT engine but when I checked the timing marks they do not correspond with the ones that I have on my engine so it probably not 100% correct.

According to manual there is a plunger stroke measuring tool which I do not have to check the pump timing. If anyone has any procedure how to check this please let me know.

here is the best picture of the pump, I dont know if that help or is visible if that has a cold start device( but there is a knob inside a cabin that I can pull in case it is too cold, but never needed to use it the whole time I own the landcruiser. I always started even by -15C.

The first time I noted this knocking sound was the day after emissions testing where they were revving the engine quite a lot to measure emissions.

I know in the video the sound is hard to hear, but in reality it is a significant change after approx 20 sec after start.

I have the stethoscope - will definitely try to trace it.

here is the picture of the pump, I dont know if that helps. Or if any other angle of the pump should be shown for better identification:

 

[Eurasiaoverland]

This is where to look for a timing alignent mark: You may need to use a mirror.

Your injection pump has a cold start device:

When the engine is hot, the arm which holds a threaded bolt (blue line) should move away from the accelerator crank at the red arrow. These external parts control the idle speed, but the internal part of the unit advances timing when the engine is cold.

Again, we really need to find out if the noise goes away when the engine gets hot. But I understand you are worried about the noise. From the video, it does not sound like a bad engine knock which could cause immediate damage, but you can hear things much better.

To check the plunger stroke requires a special tool like this:

https://www.aliexpress.com/item/1005007544380479.html?spm=a2g0o.productlist.main.107.2bbdPj4ZPj4ZGK&algo_pvid=08958dfa-f948-475f-a601-d7da52a1d253&algo_exp_id=08958dfa-f948-475f-a601-d7da52a1d253-53&pdp_npi=4%40dis%21SGD%2127.93%2120.95%21%21%2120.00%2115.00%21%402140f54217377936410993105e5b0f%2112000041234280013%21sea%21BN%214468214278%21X&curPageLogUid=iD80n1wH4iUk&utparam-url=scene%3Asearch%7Cquery_from%3A

And a dial indicator.

 

[sodafeld1]

Agree with felde and euro. I would not like to hear the hard knock noise either, doesn't sound good. Being in Slovakia I guess it's pretty cold. My Dad use to preheat his 1956 massey with a blanket all tucked up over the engine and warm her up with a blow heater underneath for 30 minutes or so during winter. She liked that. We don't get as cold as you do here. One would hope it would help.

But you may have a timing adventure ahead of you, albeit, little strange it came suddenly.

 

[matus]

Hi

thank you for advice. Tool ordered. Should be delivered next week. I will check the pump timing then. In the meantime I will check timing marks.
Currently it is not that cold .. mostly round 0 Celsius.

I dont know if it is safe to warm the engine up when I dont know what is wrong with it.. I want to prevent damaging it.

 

[sodafeld1]

Yes, I would not be comfortable hearing that clunk for any period either.
Cold for me!! haha

 

[Eurasiaoverland]

The way the noise appears after a certain time is indeed odd. There are only two things I can think of that would happen like that, one would be the glowplugs maybe turning off, but only if you have a superglow circuit - with wires going to a resistor in the intake manifold The other would be the fan clutch unlocking, but I can't see that causing any noise.

 

[sodafeld1]

Sounds like a deeper knock to me, but very difficult from a video I reckon. I read about such knocks but hopefully it is the timing. The theglob in red rocket described such a knock, but I wouldn't want to diagnose that from the internet.

After timing see how she goes.

 

[Eurasiaoverland]

Whatever the noise is, it sounds like it's happening at every combustion event, so not likely to be rod knock.

 

[Felde]

Bummer this happened after the emissions test. A real torture for the engine.
I'm pretty sure something move on that high load, affecting timing. Second @Eurasiaoverland & @sodafeld1: Go for the timing check first. I wouldn't heat it up.

But now knowing it had a max load event, I'd also consider a mechanical issue.
Still the oil from the emissions testing in it?
If so, do a carefully oil change. Collect the used oil in clean container, visually inspect it, strain it trough a fine filter, check with a magnet. If anything suspicious, we can discuss next steps, e.g dropping the oil pan.
Also a look into the cylinder with an borescope won't hurt.
But I still consider a timing issue to be more likely.
Good Luck Ralf

 

[sodafeld1]

good point on the exhaust event

 

[malden]

Matus

How long have you owned this LC? Have you not noticed variances in the sound at idle in the past? In cold weather?

I have owned an LJ70 w 2.4LT engine for 23 years and I drive it about 3 to 4 days a week these days. I listened to the video you posted five or six times now, and honestly, if that was my car I would not be very concerned. It sounds like pretty normal LT stuff to me. In cold weather I get this sound often. It goes away once the engine is warm and its been driven a bit. It also seems to happen if the car has sat undriven for awhile.

Not being there to hear it in person, I hate to give you advice. But if that were my car I would take it out for a brisk drive and see if it goes away.
Cheers

 

[matus]

Hi.

I own this car for approx 15 years now . The sound was always plus minus the same. But now this sound (unfortunatelly on video it is not that noticable) is really different and like metal on metal. That is why I would like to identify what could be faulty.
The truth is that this car is driven rarely on weekends. It is a hobby car. I never experienced that old fuel could cause this.

However I will wait until the measuring tool will arrive and then check the timing and when I do the oil change I will check if there are not any debris or metal shavings in it..

I can also try to get better sound quality and post it here so that the sound is easier to recognise.

Thank you all for proactive attitude. I will keep this thread updsted as soon as I will have some knew infos.

 

[malden]

Matus

Given your experience with the LC and if what you are hearing has a distinct "metal on metal" sound, then that is something I have not heard from my engine. That would be a concern to me. That being said, I would be tempted to warm the engine and drive it to see if the sound continues. I can only speak from my own experience, but the 2.4 LT seems to me to be a massively reliable engine. It really is the heart and soul of the LJ70 and I have never had even a hint of a problem with it. I do not let the engine sit for more than a week and I either start the engine or drive it often during a week's time. The engine wants to be driven. It does not like to sit idle. I wish you the best of luck in sorting this out.

 

[Felde]

I recommend to take your time, @matus .
Get the tool, do your due diligence.
You know your car and have yourself identified this sound not to be normal for your rig.
It came instantly not slowly, and there is that stress event of the emissions test that poses a potential reason for whatever has happened.
Wishful thinking, it might go away when warm, doesn't help.
From what I hear from the video (which I think has a quite decent audio quality): Knocking. As @Eurasiaoverland also suggested: Pretty clear diesel knocking.
That's not normal. Even my 3B at a 0°C / 32F startup sounds smoother. And that's a weekend driver, too.
Good Luck Ralf