Rattle when warmed up.

[Goldie]

Hello guys,

I've got a 1.0 Micra Twister which I've owned for about 3 months now. I noticed the sump was corroded and leaking so I've fitted a new sump.

When the sump was leaking the engine was ran a little low on oil for one journey and ever since then there is a slight rattle form the bottom of the engine when the oil is up to normal temperature.

When the engine is cold it's perfectly silent and sounds really healthy. I was using 5w30, I'm running it on 10w40 again with the new sump thinking the thicker oil may help it as it is quiet when the oil is cold and hence thicker.

Any suggestions? It's my third K11 I know the timing chains can be a little noisy, but the fact it's only doing it when warm seems like something isn't quite right to me?

 

[frank]

if running low on oil did any bearing damage it will cause ir to growl/rumble at about 3 or 4 k rpm usually goldie

 

[Goldie]

if running low on oil did any bearing damage it will cause ir to growl/rumble at about 3 or 4 k rpm usually goldie

Hi thanks for your reply!

I forgot to mention the engine only rattles at idle. When the revs increase it's absolutely fine, it drives fine too.

It's only a light tapping kind of rattle, but it's only when warmed up at idle.

 

[pollyp]

It could perhaps be worn loose clutch plate springs?

when the plate is unloaded & spins above a certain rpm like 900rpm (in neutral & clutch engaged), there's enough centrifugal force to restrain the spring against the plate housing but when it spins below the threshold rpm, there's not enough force to hold it in place so the loose unloaded springs simply fall/rattle around the housing under gravity.

during cold start the engine fast-idles to 1300rpm for a rapid heat-up then once warm it returns to a normal 750-800rpm idle.

if the rattle goes away when you slowly increase rev above idle or when you disengage the clutch to stop the plate spinning or when moving in gear at idle rpm, then it's prob a loose clutchplate spring. you'll also be able to locate the rattle is more towards the gearbox end than the timing chain end of the engine.

either retighten the lips holding the springs (if the plate was still new), or slightly increase the warm idle till it stops rattling (preferably under 1k), or simply replace the whole clutch if its been awhile, which is recommended whenever a gearbox is removed.

 

[Goldie]

It could perhaps be worn loose clutch plate springs?

when the plate is unloaded & spins above a certain rpm like 900rpm (in neutral & clutch engaged), there's enough centrifugal force to restrain the spring against the plate housing but when it spins below the threshold rpm, there's not enough force to hold it in place so the loose unloaded springs simply fall/rattle around the housing under gravity.

during cold start the engine fast-idles to 1300rpm for a rapid heat-up then once warm it returns to a normal 750-800rpm idle.

if the rattle goes away when you slowly increase rev above idle or when you disengage the clutch to stop the plate spinning or when moving in gear at idle rpm, then it's prob a loose clutchplate spring. you'll also be able to locate the rattle is more towards the gearbox end than the timing chain end of the engine.

either retighten the lips holding the springs (if the plate was still new), or slightly increase the warm idle till it stops rattling (preferably under 1k), or simply replace the whole clutch if its been awhile, which is recommended whenever a gearbox is removed.

Hi,

The gearbox has never been removed. The rattle seems to be coming from the timing chain side of the engine rather than the gearbox side.

Pressing and releasing the clutch has no effect on the sound, also if the car is moving with the engine at idle speed in gear it still rattles until the revs are increased.

It seems to me that the leaking sump, which led to a lack of oil has created this rattle at idle when warmed up. It didn't do this until the oil accidentally dropped bellow minimum on the dipstick due to the leak.

Thanks.

 

[frank]

you can go 20mm below the minimum without doing any harm goldie, as long as the oil light did,nt come on while driving
whats the milage ?

 

[Goldie]

you can go 20mm below the minimum without doing any harm goldie, as long as the oil light did,nt come on while driving
whats the milage ?

It's on about 85000 miles. the oil was just on the bottom of the dipstick when it ran low. Oh and no the oil pressure light didn't come on. It's just odd that it started this rattle when it ran a bit low.

 

[Ulrich C]

Could it be as simple as a rattling heat shield on the manifold?
They tend to corrode, and get a bit loose around the bolts. And when the manifold heats up, the material expands just a tiny bit. Maybe enough to make something rattle when warm?
Just a thought...

 

[Goldie]

Could it be as simple as a rattling heat shield on the manifold?
They tend to corrode, and get a bit loose around the bolts. And when the manifold heats up, the material expands just a tiny bit. Maybe enough to make something rattle when warm?
Just a thought...

Thanks for the suggestion, it's definitely not a heat shield though. It's an internal tap/rattle.