Noisy engine on acceleration

Hi…I’m new to the forum, just registered even though I have been peeking at other people’s woes and solutions as a guest of the forum for sometime….

I wonder if someone can help…..

I have an R registered Discovery (300TDI) with approx 120k on the clock and recently a noise has developed when the engine is under strain, mainly when the wife is in the cab…oops..no seriously…only happens when at top end revs..especially when towing something heavy…this has got progressively worse over time and I honestly think the engine is under powered in this situation….I have been told by “experts” that I have piston slap….if this the case..what is it and what can be done to resolve it…

Any help/guidance would be appreciated…

To be honest there's no point revving it that high ... most power and torque is developed from about 2000 revs and drops off after 3000 revs ... any more revs and all you're doing is wasting fuel, change to the next gear at about 3k-3.5k tops IMHO.

If it is piston slap, then it means your cylinder has somehow managed to increase it's bore outwith certain tolerances.Usually a rebuild is needed with new piston rings, etc.

Sometimes with piston slap, if it's not too bad, you can get away with new piston rings & honing the bores though this would be a temporary solution at best. Are you sure it's piston slap as it's more evident when the engine is cold & tends to quieten a little as the pistons warm & expand out a bit as the engine gets up to temperature. Could it be a noisy injector pump, camshaft, or worse crankshaft. You should maybe let a good garage have a quick listen.

chromiumuk said:

Sometimes with piston slap, if it's not too bad, you can get away with new piston rings & honing the bores though this would be a temporary solution at best. Are you sure it's piston slap as it's more evident when the engine is cold & tends to quieten a little as the pistons warm & expand out a bit as the engine gets up to temperature. Could it be a noisy injector pump, camshaft, or worse crankshaft. You should maybe let a good garage have a quick listen.

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I should have said high revs or when the engine is straining and not at start up but at anytime...currently this happens when I'm towing a caravan (not of significant weight) and trying to maintain 60mph on slight inclines…..wrt the use of the term “Piston Slap”, this came from my garage as a throw-away statement when I was discussing the problem the other month…the noise at that time only happened if the engine was significantly stressing…now it seems to happen as I’ve stated at about 60mph on slight inclines and I believe I’m not achieving the same power/response from the engine as I originally was…if it is “a noisy injector pump, camshaft, or worse crankshaft” how can identify which one…would there be other symptoms?