Land Rover Repair: Knocking the motor, piston slap, piston ring

Question
Hi John,
I have a 300TDI, the biggest peice of junk I have ever owed!
The motor was making a very harsh knocking sound from the
side of the motor,when I took it to the machanic I had him come
out and listen to it and he was afraid of driving it, but them it
stopped knocking. when I start it in the morning it makes a
noise that is the same but not as loud but as soon as I drive it
the noise goes.

I have owed many Range Rovers and love them!

This Discovery has cost me about $7000 per year in repairs for
the past 5 years the repairs have now pasted the amonut I paid
for it.

Now I have that off my chest! I would apriceate your help if you
can shed some light on this situation.

Thank you

Answer
Hi Peter,

this sounds like piston slap which is contact between the engine's pistons and cylinders.  When the piston moves up and down in the cylinder, a piston ring, called the 'ring land', should not come in contact with the cylinder wall. When carbon buildup forms, and this is a problem for many, over time the ring land starts to touch the cylinder wall and cause all sorts of noise. I'm sure this is the noise that you hear.

You will have to tear down the engine, investigate and replace your rings.  Hopefully no damage to pistons and no excessive engine wear.

Last year, I added up all the repair bills on my '95 Disco...it was nearing $15,000.  Some would say:  'hey, for a 12 year old vehicle, that's just over $1000/year!'  ...right.  I wish it was on a yearly basis.

Best of luck,

JohnMc