Engine noise

gday every one ,i hope someone might be able to help me,i have a rattle when i start the engine mostly when cold but sometimes hot. sounds as if its on the right side of motor, battery side, only lasts 30 seconds then goes.any thoughts.

There could be several things that might change as the engine temp rises. The first thing I can think of is injectors, and failing that, water pump. I'd go with injectors first.

You could try tossing some 2-stroke in and see if that quiets your injectors - but there's risk involved. I use Castrol Activ 2T Jaso FC in mine and mine idles like a petrol engine, quiet as a mouse. Then again, mine is not yet a month old and it's done less than 4,000km.

Yours might not react the same. Mine got quieter, but the 2-stroke may have a detergent effect and could loosen or remove varnish from injectors or your bores. It could result in excessive blow-by, or clogged injectors - the chance of that is slim, but it's there nonetheless.

sorry, a bit off topic...

whats blow by? heard the term a few times, not sure of the meaning though?

Injectors, ever run a injector cleaner through it ?

Dave.

engine are difficult to compare over the net.

at a guess either low oil pressure on start up causing a few rattles untill preesure is up.
or noise from injection pump. could possible have air getting into the pump. check fuel filter.

whats blow by?

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As the fuel/air mix in the chamber combusts, it tries to push the piston down. Since the seal between the piston and the wall of the cylinder is achieved by a series of small rings, it's good but not perfect. A small amount of the combustion makes it past those piston rings and into the crank area.

When you are reassembling your block (if you ever do), you should make sure that the little gap in the rings are spaced around the piston. If you leave them all nicely lined up, you're just presenting a nice channel for the combustion gases to pass straight into the crankcase.

Diesels are worse for it, because of their higher compression.

This is part of the reason why you need to change your engine oil regularly. It's also why you can't seal the crankcase, or block the PCV (positive crankcase ventilation) hose.

macca said:

gday every one ,i hope someone might be able to help me,i have a rattle when i start the engine mostly when cold but sometimes hot. sounds as if its on the right side of motor, battery side, only lasts 30 seconds then goes.any thoughts.

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I had two similar rattles in a similar spot which I thought went away after a while but I'm not so sure now. One was the original driving light relay that Nissan mounted, nut and bolt were cross threaded so never did up tight, fixed that and replaced the relay anyway.

The other was the battery mount, I was suprised how loud that little sucker was, that however was my fault because I mounted the battery isolator on the bolt for the battery tie down and didn't do it up as tight as I needed too. Probably neither are your problem but it does pay to check everything, even the things you do yourself.

thanks for the advice, yes i do run injecter cleaner,and just done fuel filter, its just a mystery,as it does not do it all the time. anyone know a good diesel mech north of brisbane?

macca said:

anyone know a good diesel mech north of brisbane?

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No but if you find one let me know.

Dont know if there is a fuel regulator on these engines, but worth a look at that if there is one, might be faulty and not have enough pressure at start up.
Mine used to make a knocking noise and i found out it was the glow plugs, only 1 was glowing which made the other 3 cylinders barely running when started which made like a knocking noise till they reached their temp and ran properly.