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Noisy LC 120 Diesel

Scottish120

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I have written a similar post on here before but I am determined to get to the bottom of this problem.

120 LC4 2004 manual, vehicle drives fine, starts well, goes well and has no flat spots. Engine ticks over smoothly on idle and isn't noisy but has a fairly loud "tappety noise" when you drive it. It's not a knocking sound it just sounds like a badly adjusted tappet. As soon as the engine comes up to temperature the noise reduces by about 75%, in fact you can hardly hear it on the overrun. Local garages have tried to diagnose the noise (which seems to come from the top left hand side of the engine when sitting in the car) but haven't managed as yet.

So far we have changed injectors. Old injectors were actually pretty good and nothing was excessively choked in carbon and the seating washers were fine, not blowing past. The noise is exactly the same with the new injectors as was with the old. We are 99% sure the noise is not from the injectors.

The fuel vacuum switches have also both been changed and this had no effect on the noise.

The engine has had two oil changes with good quality oil in the 7 months I have owned the vehicle and that has helped a little.

It is like someone throws a switch the minute the thermostat opens and the noise reduces, don't know if that is a clue? Temperature remains constant as you drive

Local garage has told me to keep driving it and see if the noise develops but I want to know what is causing it! Someone somewhere must have experienced the same thing and maybe even found the cause.

Any advice gratefully accepted. Thanks
 

Dave_S

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Dumb question maybe - but have you driven any other LC4 120s? Always good to be sure what " a good one" sound like. Sorry if I'm telling granny to suck eggs...
 

Higgy

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Is there any loss of power?...... Has the Engine management light Been thrown up Ever.... Does anyone know if the LC4 shared the same Turbo as the LC5...
 

Scottish120

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Thanks for your replies, no power loss the Cruiser goes well. I have driven other LC120s so I know what they should sound like, also my local garage is familiar with this engine mostly in the Hi Lux so also are aware of what they sound like. No fault codes have shown up.

It's an annoying mystery!
 

Juddian

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I bought my first LC in '97, a 70 series 3.0 litre, about 4 years old and 39/40k on the clock.
Ran superbly, and the first thing i did was give it a good service using a standard (probably 15w40) oil of a make common in every motor shop
A few weeks later and the engine sounded like it was rumbling, and i mean big/main ends rumbling, went to Toyota garage, mechanic came out had a listen and said better get it booked in for full rebuild...not what i wanted to hear.

Wanted a second opinion cos couldn't believe a Toyota engine could be worn out in such a low mileage, so drove gently over to the now long gone Toyota garage at Collyweston (Stamford), should have gone there first as the mechanic there was the font of all knowledge on LC's, he used to build and off road serious 70 series motors...he came out revved the engine a couple of times and told me to drain the present oil out of the sump and put another oil in, his choice of words was somewhat more colourful and i'll leave you to imagine the turn of phrase.

I did exactly that and the engine sounded good again, it never gave a moments trouble and some 5 years or so later the vehicle was sadly written off in a crash (but due to brick outhouse build quality saved my good lady from injury, so glad she wasn't in her Punto), some months later i got a phone call from a chap in Bradford who had bought the vehicle to rebuild, very nice fellow too, sent him the genine Toyota workshop manual i had and the spare key etc...he commented how sweet the engine was, and was over the moon when i informed him it had seldom if ever gone more than 3000 miles between oil changes in the probably 60k miles i put on it.

This elongated tale i relate because the only cause of the noise on that 3 litre lump was the oil, so wondering if its maybe worth giving the engine another oil change but with something different, obviously you've had a look at the pick up strainer already?

Currently and usually use Branded 5w40 oils just as i did with the previous Hilux 3 litre, preferably synthetic preferably Diesel specific, when available in bulk 20 litre packs at a fair price, have also used Exol 10w40 Diesel spec semi synth which is fantastic value but prefer 5w for winter start ups, i've used Millers Morris, Fuchs, Castrol etc all have been good, i tried Shell Helix but the engine sounded rattly to my ears so won't use that again, same with Comma.
Despite how long modern oils are supposed to last, and bearing in mind the vehicle sees a good number of short runs, don't think the engine has gone beyond 2500 miles between changes.

Also, have found the time it takes for the oil light to go out is not the same with all oil filters, i bought some Wix filters and it took a couple of seconds to go out on cold starts, currently using Hengst filters and the light goes out immediately.
 

Scottish120

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Thanks for your reply. The engine is quieter than it was since its second oil change. I haven't removed the sump to check the pick up pipe, it would have been done when the injectors were changed but as the washers were good and not blowing past the sump was never removed. Oil has been replaced with good quality but to the same specification as Toyota recommend. Maybe this is worth investigating further.
 
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Juddian

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Don't need to remove the sump, the oil pick up is directly over the sump plug on a 120, if you allow it to drain for several hours or overnight till it stops dripping, remember to remove the filter which can only help drainage, then via torch, camera, endoscope you can see all you need to without disturbing the secondary sump at all, i do this every or every other oil change.

The reason i went back to Diesel specific oil is the (assuming) better detergent qualities in Diesel oil.
When i had the Hilux, from new, the oil would stay clean for roughly 1000 miles, when i first got the 120 (used but very good history and conditon) it blackened the oil quite quickly, after a couple of short changes it got better and now like the Hilux is staying clean for getting on for 1000 miles...whether the Diesel specific oil has done a better job of cleaning things up i don't know, but can't do any harm from my way of thinking.
 

Scottish120

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I used to change the oil on my Land Rovers every 5000 miles and it was a good policy. My Cruiser has good service history up until 113k miles. It had 135k when I bought and in that time wasn't particularly well looked after so I'm trying to make amends. Will try putting diesel specific good oil in it .
 

karl2000

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Is there any way you can get a video/recording up so we can hear it?
 

Scottish120

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This is it before the engine is fully up to temperature
 

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Bob

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That sounds exactly like my 1KD 90 series on a cold morning.. I'll has always sounded like that, mainly in winter, and I've had it since 72,000 miles (practically new) and it has 360,000 on it now. I have never changed injectors, nor opened the head, nor anything bar SCVs.. and it drives as good today as it did 13 years ago when I got it. Like you say, it's like the flick of a switch after a few minutes driving and it's quiet as a mouse then.. I think it's a characteristic of these engines, especially the earlier ones.
 

Scottish120

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Wish it was quiet as a mouse once it has warmed up, the noise never goes away and on other 120s or Hi Lux that I have driven there is no noise like this.
 

Juddian

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I'd have a poke nose around the exhaust manifold.
 

Scottish120

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Exhaust system has been been smoke pressurised from the tail pipe up to the manifold because that is what we thought it was but it didn't find any leaks.
 

Juddian

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Bugger, it sounded just like a manifold crack.

Have yout tried the old fashioned screwdriver as stethoscope trick to try and track down the noise.
 

karl2000

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Have you looked at (recorded) the live data, especially during the transition from it making the noise to it stopping making the noise?

Obviously it's getting up to temp, but I wonder if anything else changes that live data might show up?

EGR valve is top right isn't it?
 
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