New diesel engine making real knocking sounds when revved up

Submitted: Saturday, Feb 18, 2012 at 12:29
ThreadID: 91937 Views:4684 Replies:4 FollowUps:3
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Hi All, just wondering if there is a diesel mech can tell me if it is alright with the knocking sound whilst idleing up my hilux diesel 2l-t?

is that normal for a new diesel engine?
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Reply By: Kimba10 - Saturday, Feb 18, 2012 at 14:26

Saturday, Feb 18, 2012 at 14:26
Mate Im not a mechanic but you shouldnt have a knocking sound and especially on a new motor ?? Unless is diesel knock which is fuel related (air in line) I had this with my 2.8D when I changed the fuel filter one day, it still ran fine but sounded like a big end knock untill my mechanic mate said no its diesel knock (had never heard of that term before) was my first diesel vehicle but must say it did seem to have it as the klms got high (300 thou) but only on start up (only very very minimal) but would go in a few seconds so may have been oil pump starting to get a bit lazy ?? Sold it anyway and still going strong today...........
AnswerID: 478065

Reply By: Member - Royce- Saturday, Feb 18, 2012 at 14:35

Saturday, Feb 18, 2012 at 14:35
Bit confusing whether you are idling or revving? Anyway... I would do either until you get it checked, because it certainly isn't okay.
AnswerID: 478066

Follow Up By: vk1dx - Saturday, Feb 18, 2012 at 21:39

Saturday, Feb 18, 2012 at 21:39
I agree with Royce. We cannot hear it and I for one am not a mechanic.

Take it back to whomever put the motor in. Get their impression and if they say it's okay take it to another diesel mechanic and ask again.

FollowupID: 753548

Reply By: Dust-Devil - Saturday, Feb 18, 2012 at 22:04

Saturday, Feb 18, 2012 at 22:04

I'am not a diesel mechanic, however I do believe that a 'NEW' diesel engine shouldn't make the noise you are describing.

There is a member of this forum who very recently had a OME brand new from the factory diesel engine fitted to his heap of crap 'Missin Nissin' 3.0l, From initial startup this new engine had an extremely pronounced Rattle/Knock, depending on how your ear heard it.

It was finally diagnosed as a timing fault. The timing had been set one tooth off from where it should have been.

Once re set it was a whole 'new motor' again.

Point being, don't assume that the OME has produced a perfect product. You problem may be something else again, that requires an inspection by someone who knows exactly what they doing.


AnswerID: 478093

Follow Up By: Member - Christopher P (NSW) - Sunday, Mar 04, 2012 at 14:01

Sunday, Mar 04, 2012 at 14:01
timing is 100% perfect! so it must be fuel. sounds like i send it off to diesel mechanic.
FollowupID: 754893

Reply By: howesy - Thursday, Mar 08, 2012 at 10:21

Thursday, Mar 08, 2012 at 10:21
I had this happen to a new fully reconditioned diesel engine once before in a hilux. Took it back to mechanic and he said basically tried every bit of B/S under the sun to avoid pulling it down.
First he said Injectors so $800 later (diesel injection specialist) his next best guess was injector pump $1000 later (diesel injection specialist) good thing was at least there was nothing else to pick on so I went back and told this wanker that engines dont knock for no reason. He went over it with a stephescope and reckoned he could only hear normal diesel engine noises.
Basically most will tell you any lie to avoid their obligation hoping your pissy warranty period on diesel engines will run out before it goes bang.


most of these idiots simple send the head to a mate or ather workshop to get a head skim. Good practise but before fitting they fail to centre punch the pre-combustion chambers to spread them tight into place and the skimming process actually loosens them. Not that you would see but enough that after a little running they become loose.
Mine dropped far enough that the piston smashed F@%k out of it disintegrating the piston stuffing the con rod, splitting the bore and destroying the head. I had to threaten court action before he agreed to fix it.

First thing is, get a long bar or screw driver or stephescope and you will here the knock narrow it down to if its from the top end. If so it can only be one of the things I have mentioned. injectors, pump, or pre combustion chambers.
AnswerID: 479860

Follow Up By: Member - Christopher P (NSW) - Thursday, Mar 08, 2012 at 11:46

Thursday, Mar 08, 2012 at 11:46
this is a brand new motor. I have narrowed it down to my old 2.4 injector pump isn't up to the task of fueling it. and the 2lt ip needs some seals and another bit (thermostat choke/ extra fuel thing on side of pump) as it ran sweet with it in, but smokey as. so i will get that resealed and a new thrmostat thing for it and redo ip swap out. then start it again and take it for a run.

will check your suggestion to make sure. thank you
FollowupID: 755317

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