KV6 engine rattle/grinding - *not* inlet manifold?

ianM · 12th October 2020, 13:09

Hi all,

Since I bought my 75, it's had a bit of an odd rattle from the engine - in fact, it sounds more like a grinding noise than a true rattle. It's normally only when cold, it happens at bang on 1,100 revs (whether going up or down past it), and seems to all but disappear when the engine's warm. If you leave the car idling after starting the engine, it'll sound something awful as the revs come down to 1,100 with a persistent metallic grind, before going back to normal as soon as it's gone past it.

Of course, this being a KV6, I assumed it was the inlet manifold - but today I got the inlet manifold replaced with a replacement I was assured was rattle free from the trader I bought it off, only to find the dreaded rattle remains.

As far as I can tell, this only really leaves two options. Either the one I've replaced it wasn't really rattle free - or, it's something other than the inlet manifold. I'd like to assume I can write off the inlet manifold now, but if it's not that, what else could it possibly be? Is there a list of things I ought to check next that may cause a rattle, trying to figure out where it comes from?

12th October 2020, 13:09	#1
ianM Regular poster Rover 75 2.5L V6 Saloon; Rover 214i Join Date: Sep 2010 Location: West Midlands Posts: 86 Thanks: 18 Thanked 1 Time in 1 Post	*KV6 engine rattle/grinding - not* inlet manifold?** Hi all, Since I bought my 75, it's had a bit of an odd rattle from the engine - in fact, it sounds more like a grinding noise than a true rattle. It's normally only when cold, it happens at bang on 1,100 revs (whether going up or down past it), and seems to all but disappear when the engine's warm. If you leave the car idling after starting the engine, it'll sound something awful as the revs come down to 1,100 with a persistent metallic grind, before going back to normal as soon as it's gone past it. Of course, this being a KV6, I assumed it was the inlet manifold - but today I got the inlet manifold replaced with a replacement I was assured was rattle free from the trader I bought it off, only to find the dreaded rattle remains. As far as I can tell, this only really leaves two options. Either the one I've replaced it wasn't really rattle free - or, it's something other than the inlet manifold. I'd like to assume I can write off the inlet manifold now, but if it's not that, what else could it possibly be? Is there a list of things I ought to check next that may cause a rattle, trying to figure out where it comes from?