XR6 LPI ticking noise from rear of engine

[Zeksta]

Hey guys, long time lurker, first time poster.

 

I've just recently purchased an 2013 XR6 LPI and I've been hearing an odd knocking noise coming from the engine. It sounds almost as if it's coming from the exhaust manifold and may even be my catalytic converter.

 

Taken it to mechanics and they're saying the car seems fine, taken it to a muffler specialist as well they've said there's been no issues so I'm a tad stumped. 

 

Attached is a video of the sound. Any helps would really be appreciated!

 

[k31th]

 

The LPi injectors do make a ticking noise, but not like that... that sounds more like a exhaust manifold gasket leak or maybe something further down the exhaust with a leak.

[Zeksta]

Yeah that's what I was thinking as well but had a muffler specialist take a look and even delve in to the catalytic converter and reckons there's nothing wrong with it or it may be melted in the middle?

 

I'm getting a little bit of a hesitant acceleration as well and slightly lumpy idle. Pain in my ass to figure out 😂

[k31th]

yeah, that sort of symptoms does point to a collapsed catalytic converter... get it inspected by an exhaust shop via remove and inspect... they should be able to also track down where a leak would specifically emanate from.

[Zeksta]

Yeah was thinking might get the cat swapped as well. Can that sound also sound as if it's occuring from the engine bay as well where the exhaust manifold is?

[k31th]

maybe, maybe not... depending on how the problem occurred and how it specifically occurred, but the cat is just below the rear of the engine, so it's possible.

[Zeksta]

Interesting, it's definitely been a touch of an annoying problem to figure out. The video I upload was just from underneath the front right wheel arch, the sound, sounds as if it's coming from the engine bay/manifold a touch more.

 

Is it possible it could be heat shield or even sticky lifters?

Edited 07/02/21 10:22 AM by Zeksta

[k31th]

yep, it's possible it's a lifter noise, but you wouldn't hear it like that, it'd mainly only be audible very close to the engine block and usually happens at the front of the engine rather than the rear (but it's possible for the rear).

 

Heat shield is a distinct possibility but those sounds normally change with heating up and cooling down cycles of the engine and is much easier to diagnose as you can either t,  see them vibrating or stop them vibrating easily to diagnose the sound.

 

From the position you took the video, it seems likely my first suggestion is it, a multi-layered gasket leak, e.g. the manifold one.

[Zeksta]

Good to know! Yeah there's a bit of pinging noise that comes from engine on cold start-up which then slowly transitions into the noise you hear in the video.

 

But either way you've been a God damn massive help! Definitely going to try to get this further diagnosed, would a gasket leak also cause hesitant acceleration and lumpy idle as well?

[k31th]

That cold startup noise is probably just the gas injectors ticking and then quieting down as it gets warmer, but hard to be sure without an example.

 

Lumpy idle and hesitant acceleration, as I said, points more towards a catalytic converter problem than a gasket leak, but if a leak is bad enough it could cause problems like that but is less likely.