Piston slap

i have been told that my disco 200 tdi has piston slap .
what does this mean and is it terminal ?
Please help

It means your pistons are worn and loose in the bores allowing them to slap about causing noise. You're looking at a rebore, new pistons and rings, so not terminal but a few undred quids worth and probably find some more stuff worn out when it's stripped. If it isn't running too bad though it could go on for ages just being a bit noisy and/or smoky.

cheers
it's running find just abit noisy while on tick over woudl changing the oil help ?

does it chuck out smoke under acceleration?

only when it's cold otherwise no why ?

well if yer had piston slap then oil would be making its way into the cylinders and burning with the fuel, causing black smoke. it sounds like yer oil aint getting up to the top fast enough. change yer oil and filters but flush it with half a gallon of diesel before you fit the new, that should clear all the **** out of your oil pump

Will try that as it's not had an oil change for a while and done alot of off-roading will try it tomorrow and get back to you

Cheers

royal452 said:

only when it's cold otherwise no why ?

Click to expand...

Piston slap is usually the skirt of the piston that has worn, and usually on the thrust side, but it's quite difficult to diagnose. I have not really seen many to be honest and the ones I did were on performance engines reving their nuts off. When the skirt wears the piston loses it's ability to travel up the bore square and results in the piston rings and the top end of the piston failing, but it could take a while.

If it's a diesel its slow reving and less likely to do this, and I personally have never had one, but I guess it could happen.
.
Was the person that told you legit, and it's not something else like a diesel knock.

he was my dad so not a mechanic but has raced and worked on cars for years i thought it was the water pump but will change the oil and see what happens ? i have no milk or ab-normal lose of oil ? just sounds rough on tick over whats diesel knock ?

yella said:

well if yer had piston slap then oil would be making its way into the cylinders and burning with the fuel, causing black smoke. it sounds like yer oil aint getting up to the top fast enough. change yer oil and filters but flush it with half a gallon of diesel before you fit the new, that should clear all the **** out of your oil pump

Click to expand...

I think if the pistons were as bad as you say yella, then your right he would be getting more problems than just a knock, and billowing out clouds of blue smoke, with starting probs. He would be chucking gallons of oil in it.

It's also only aparent on idle, usually it knocks when you blip the throttle, a very heavy distinct rattle, unlike the big ends.

I think he needs a second opinion, wonder if it goes away when he presses the clutch?? and it's the crank moving in the thrusts.

royal452 said:

he was my dad so not a mechanic but has raced and worked on cars for years i thought it was the water pump but will change the oil and see what happens ? i have no milk or ab-normal lose of oil ? just sounds rough on tick over whats diesel knock ?

Click to expand...

Sometimes if the pump timing is too far advanced it causes the engine to produce a heavy knock, and it sounds if the engine is knackered, you dont seem to be using oil and its fine otherwise.

When the pistons wear to the extent of knocking it burns oil, and you make no mention of this.

Also if your idle speed is too low you get this kind of knock

it's an auto so can't check the clutch but it goes quiet as soon as i raise the revs

How do i sort out the pump timings ?

royal452 said:

How do i sort out the pump timings ?

Click to expand...

Is it not idling too slow??, just a dab higher to take it away, some of the truck engines I have worked on sounded like they were going to explode when the idle was too low.

Adjusting the pump timing requires you to mark it first and then slacken all the nuts at the rear of the timing casing on the pump flange only enough to move the pump a tad. Turn the top of it to the engine to retard it, but the pump has no real proper adjustment and you will be limited, but it will move.

An engine noise in near impossible to diagnose on here, but give these a try.

would a service help to find out whats wrong ? not had one for a long time

royal452 said:

would a service help to find out whats wrong ? not had one for a long time

Click to expand...

How long is a long time, I think yer dads gona get the big slipper out lad.

I think if it's that bad then refer to the chap wif the oil change and diesel to clean it, and good engine oil, not that symphetic ****, it's too thin for an old engun and will run out everywhere.

And yer dads gona get slippered as well for letting you, and diagnosing piston slap with **** oil in it.

Better get yer mom to look next time.

If it was yer dad that told yer it was piston slap why didn't yer ask him what he meant?

aye, if he were anything like my old chap, when yer questioned him on anything he would say "work it out fr yourself lad" it werent till i was a bit older that i realised the old bastard hadnt got a clue what he was on about

i have been to the garage and he told me i just have a noisy engine with a noisy water pump

Wont tell my dad he's a duff otherwise i wont get any pocket money hehe as long as it keep driving around tixover i'll be happy