Greetings all,

It's that time again...

What noise is this? What should I be looking at as a source?

It isn't 100% of the time, but seems more present when I'm stopped at idle. Sometimes it's completely missing, others overbearingly loud. It disappears above about 1K RPM, and changes in sound based on previous rev activity.

 

Crikey. You don't have WWII diesel submarine as a poll choice.

Seems to me like you should be able to narrow down the location due to the volume.

Is it at first start up, or after warmed up? What's your running temp? When it's banging like that?

 

I'm at 194 solid on the freeway, and between 197 and 206 in traffic. I suspect I have a fan clutch that needs to be replaced, but the tapping/clacking noise has been there much longer than that.

It's really curious to me that it changes with RPM, but isn't always present when the engine is warm. For example, it's usually, but not always there when I drive the 30 miles home from work.

I'm secretly hoping it's something like an emissions system component, water pump, pulley, or some such I can replace, and have the issue magically disappear. I don't really think that's likely.

 

Remove the fan clutch and start it up.


Take a hose, 1 inch or so diameter, couple feet long, put it to your ear, take the other end and direct it around the engine till you find where it is loudest...then do some careful hypothesizing...


Off the video it sounds like a rod or bearing knock, but videos can be deceiving.


If you could pinpoint it, top or bottom, do another video it might be more noticeable.

Also, I have heard a rover rocker clak pretty loud...

 

I love this game. I wish I knew how to do a poll. Mine would be "sell it, suffer it, drive it off a cliff, or set it on fire and roast marshmallows over it.'

As to your poll, what a horrific noise.

I can't tell on my speakers but my first reaction was a blown head gasket exhaust leak or some other exhaust leak. Then you pressed the accelerator and dashed my guess. Is it a metallic sound? Do you have low oil pressure? If so I change my vote to a spun cam bearing. If not I want one more guess... Maybe two.

 

Right, excuse my ignorance as the Rover V8 engine is not my forte. Can you slacken the main belt adjuster or remove the serpentine belt totally. If you can then either slacken the adjuster a lot or remove the belt. Then start the engine and see whether the noise disappears and if it does you've eliminated it down to one of the accessories. If it doesn't it must be within the engine itself. Unfortunately, listening to the vid it does sound like a slipped liner as the noise increases with rpm, but, video/audio recordings can be very deceptive. Good luck.

 

It sounds like a damaged cat. Broken internals rattling against the metal at low pressure(rpms) and disappears when revved(pieces pinned by exhaust pressure). Sound should be under pedals or glovebox, not from engine, if so.

 

Yeah, I need to figure out where it is. I'd not thought of the hose idea (I was going to go the mechanic stethoscope route, but both seem to have their advantages).

I was pretty concerned when I heard it the first time... But it's been happening for a couple years, starting about two months after I got it. It's a daily driver right now, otherwise I'd go for the gusto with the ol' learning experience of "take everything apart and find it". Can't do that over a weekend with a car I need that Monday.

It sounds like something mechanical clanking or hitting something to my ears. I guess that could be metallic, as the whole assembly is metal.
Oil pressure is... fine? I don't have an oil light illuminated, but I also don't have another way to measure it connected currently.

Pulling the serpentine belt does seem like the simplest way to test. The catch is the noise isn't constant. It varies... I need to watch temps on the ultragauge (which I noticed was just barely starting to flicker today), and take notes for a couple days to get all my factors laid out.

 

With it going on two years and varying when you hear it still makes me think cats.

 

I have the exact noise and the same changes with RPM. I should know in the next week or so if its the liner (what I suspect) as I just had the PS head gasket fail on the rear leaking coolant on the ground. It runs the same temp as yours with the lower t-stat and never overheats but who knows before me. I did have to add about a quart of coolant every 1.5k or so and this failure wasn't unexpected, are you adding any coolant?

I am 99% sure it is nothing to do with Cats or Trans in my case. I have the new bolts, gasket kit on order and will tear down to see.