200 tdi engine rattle

hi

my 200 tdi has quite a loud rattle on her - she starts fine and runs ok, you can rev it high at a stand still and it wont rattle but as soon as you drive it and put your foot down it rattles quite loud, do you think it might be the pistons/ rings that might be knackered?. i also had the glow plug out and number 2 and 3 were covered in black oil.

any ideas?

With oil on the plugs it's probable the rings have ceased doing their job, but i can't see that causing a rattle only in gear, you would hear it all the time Ad. You saw what my plugs were like and the pistons on the 200Tdi, plugs under normal conditions should be clean of any oil trace.

The only other rattle i can think of with the pistons is piston slap caused by worn cylinder sleeves, but again, you'd hear that all the time.

Sounds like the rattle could be something close to the engine perhaps?

is exhaust interfering with the body? a change in rpm will cause a change in frequency of vibration of anything with a bit of play in it!

are engine mounts ok? (not cracked loose etc..)

does the clutch slip or give any funny noises?

have you checked to see if its a cracked brake disc etc..

i have a nasty feeling it might be piston slap, might just bite the bullet and wip the head of as the landy is in my garage now for a while as its missing a tranny box.

Wait a minute, you might not need to whip the head off just yet! I have a feeling that you may have an injector problem, and it is certainly something you can check before you whip the head off (and it is good practice to take the injectors out before you whip the head off anyway).

First of all, if you build up some speed in fifth gear and allow the vehicle to coast at around 45-50 mph on a gentle descent, do you notice the rattle more as you come off the throttle slightly, with just enough throttle to allow the engine to coast and maintain speed?

Also, would you say the rattle is fairly consistent / does it maintain a steady pattern, or is it more random?

The black oil that you see on the glow plugs could well be quite a few things. I would like to suggest that it could be soot / carbon build up which is created by an injector over fuelling in that particular cylinder. The injector may have a worn nozzle or spring which is allowing fuel to leak into the cylinder when it should be completely sealed off, or it could even be a leak between the nozzle holder and the nozzle it's self which is allowing fuel to dribble into the cylinder. The excess fuel in the cylinder will create pre-detonation (diesel knock) and it would also explain the wetness on the glow plugs (diesel and soot build up combined).

If you whip each injector out of the head, examine the lower part of the injector (I.e. Around the nozzle and copper washer area) for wetness. If you find one that is damp (they should be dry), you've got a leak and it may well be causing your knock.

You can check each injector by connecting the injector pipe the pump in a way that allows you to position the injector so that you can examine the spray pattern. Turn the engine over (on the starter) and examine the spray pattern. If you've got an injector that is dribbling diesel, there's your problem. If you notice an injector body leaking, this could also be causing the problem.

It's worth having a look
-Pos

cheers pos i will have a look at that in a couple of days time. the rattle is in all the gears but only if you boot it, the landy does seem to be lacking power also. aso mabye be the injectors, will have a good look at then on tuesday and keep you posted.

Any news man?

-Pos

not yet mate just got in from work and am knackered, need a shower and some sleep.

Not sure why an injector would cause a rattle under load Pos? Your advice is sound but I can't see how this co incides with Ad's problem, the glow plugs being oiled up is down to oil in the top half of the cylinder and is completely different to a carbon build up ( which is dry & not wet )

PaulWilde said:

Not sure why an injector would cause a rattle under load Pos? Your advice is sound but I can't see how this co incides with Ad's problem, the glow plugs being oiled up is down to oil in the top half of the cylinder and is completely different to a carbon build up ( which is dry & not wet )

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I was trying to determine what kind of rattle he's hearing. My engine had developed a horrible rattle (diesel knock) which was particularly noticeable on over-run, and it was caused by two injectors leaking between the nozzle body and the nozzle holder. The fuel was literally dripping into the cylinder when the injector should have been closed (i.e. with piston beginning on its downward stroke). The excess fuel had created lots of extra carbon per combustion cycle which built up as a thick soot on the tips of the injectors and the glow plugs in the two effected cylinders. As the diesel had come out of the injector nozzles, it had then soaked into / amalgamated with the sooty carbon build up to make a thick, wet, black sludge - much like oil. I thought that I had worn valves or a blown head gasket at first, but a leakage test proved differently, with excellent scores across all four bores.

I cleaned the injectors up, installed new nozzles my self and then had the pop pressures set at my local diesel centre, (where the leak was discovered) and the engine is spot on now. The knocking sound has vanished and the engine runs much smoother with a lot more power. It is very possible that he has one or more injectors which aren't behaving correctly. I suppose if one of the two internal injector springs have failed it could also create an annoying rattle although I'd put money on the internals being alright. It's worth him checking before he whips the head off

-Pos

Well mate, i learn something new every day

piston slap doesn't sound like a rattle either

yes am going to try and get them out on thursday as i have to spend tomorrow night with the wife as i havent seen her for 9 days.

big ad said:

yes am going to try and get them out on thursday as i have to spend tomorrow night with the wife as i havent seen her for 9 days.

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Bloody hell do you work on an oil rig or something?

PaulWilde said:

Well mate, i learn something new every day

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It's a bit of a long shot I know but it's worth while investigating before he decides to whip the head off completely. If his injectors are fine then I'll eat my hat!

The rattle will more than likely turn out to be something more simple, like a valve stem missing a stem cap, an over generous valve clearance or it could even be the vacuum pump starting to pack in (mine creates a nice rattle). It could even be something clutch related.

As for the oil, like you suggested, more than likely the valve seals! You never know though.

-Pos

I'd still be suspicious about the fact that it revs ok when at standstill but rattles when moving. I'd be thinking transmission, hubs or exhaust. It's difficult to tell without hearing it.

I like your idea of injector testing, pos. Is this basically how a specialist would do it? I guess a defective spray pattern would be obvious compared to a normal one. My 300 does strange things such as losing power and smoking a bit heavily from the exhaust but only sporadically. I'm thinking of an injector test since I've had fuel gelling problems causing a blocked filter. Also it has done 120k miles.

pos said:

Bloody hell do you work on an oil rig or something?

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lol no mate the missus is a profesional chef and works all over the country so shes away for up to 2 weeks at a time sometimes.

he'll be pished off after having stripped his engine apart only to find it's a loose exhaust bracket

check the simple things first !

crumplezone said:

I'd still be suspicious about the fact that it revs ok when at standstill but rattles when moving. I'd be thinking transmission, hubs or exhaust. It's difficult to tell without hearing it.

I like your idea of injector testing, pos. Is this basically how a specialist would do it? I guess a defective spray pattern would be obvious compared to a normal one. My 300 does strange things such as losing power and smoking a bit heavily from the exhaust but only sporadically. I'm thinking of an injector test since I've had fuel gelling problems causing a blocked filter. Also it has done 120k miles.

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being a plant fitter i know that this sound if definetly a engine rattle over anything else, was just asking to see if anyone else had a similar experiance.

crumplezone said:

I'd still be suspicious about the fact that it revs ok when at standstill but rattles when moving. I'd be thinking transmission, hubs or exhaust. It's difficult to tell without hearing it.

I like your idea of injector testing, pos. Is this basically how a specialist would do it? I guess a defective spray pattern would be obvious compared to a normal one. My 300 does strange things such as losing power and smoking a bit heavily from the exhaust but only sporadically. I'm thinking of an injector test since I've had fuel gelling problems causing a blocked filter. Also it has done 120k miles.

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A specialist might have a couple of different bits of equipment to test injectors. The simplest tool is essentially a bottle Jack like canister with a manual pumping / priming lever, an injector pipe and a pressure gauge. The engineer will then pump the lever, forcing diesel through the injector and it will allow you to determine the opening pressure (pop pressure) of the injector as well as the condition of the spray pattern. Holding the pump just below popping pressure for around ten seconds will also show whether nor not the injector nozzle is seating correctly, preventing fuel from leaving the nozzle and entering the cylinder before or after it is required.

More advanced equipment will perform things like a chatter test, accurate leak off test and in the case of 200 and 300 tdi injectors, will give the primary and secondary opening pressures. The primary opening pressure measures the injectors performance at idle, and the secondary pressure measures the injectors performance at higher rpm's (I.e. When you're shifting )

Generally speaking though, if you whip an injector out, spin the injector pipe around and then connect the injector back up, it should give you a good idea of the spray pattern. You're looking for a nice even shot of fuel in almost a straight line leaving the nozzle tip from various points as opposed to a wide "fan" of spray. Do not put your hand over the end of the injector whilst it's operating and do not breathe in the atomised diesel, if enough of it gets into your blood, it will kill you.

A diesel specialist should check them for around a fiver per injector. I bought four new nozzles, installed them myself and then had a specialist set the pressures. All in all it cost me £130 for a set of four like new injectors. Most places will charge around £250 for the whole job.

-Pos