Clunking sound on very cold start

[Untyped]

Previous issue posted here regarding the choppy idle/rpms got fixed with an upstream O2 sensor replacement but I am puzzled about this one....

When it is extremely cold(bellow -15C) car starts fine but there is this rhythmic clunk sound coming from front of the engine... of course the first thought it is timing chain issues but I feel like that is not the case. It stays for 2-3 mins and fades fast. It sounds like it's coming from the fan/radiator area.

I removed the oil cap and put my ear there to see if it is inside the engine but no... it sounds very external.

I am attaching a video that captures the sound very well and how it fades off.

 

[scapistron]

Might be motor mounts. With the hood open how much do you see the engine move when you rev it up? You can also check the clearance between the intake pipe and the fan shroud.

 

[Untyped]

Might be motor mounts. With the hood open how much do you see the engine move when you rev it up? You can also check the clearance between the intake pipe and the fan shroud.

Will do those checks later. But I am pretty sure the engine does not move much under rev.

For the second option.. why would it disappear when slightly warm?

 

[JDiehl]

Watching this thread. Had the same issue last winter on some very cold morning starts but forgot about it until now. FYI my timing chains have been updated.

JD

 

[alldazed]

I have the same noise .on a 2011 RRS . It’s something to do with the fan clutch and I don’t worry about it . Been doing it every cold day in the winter at initial start up since I bought it 5 years ago.

 

[txfromwi]

Interesting...

 

[Untyped]

I have the same noise .on a 2011 RRS . It’s something to do with the fan clutch and I don’t worry about it . Been doing it every cold day in the winter at initial start up since I bought it 5 years ago.

Nice! That's reassuring. Did not know there is a clutch there but I can totally "picture" the sound now.... there was a moment where I told myself that is the AC compressor clutch but obviously wasn't....

Thanks for your comment!

 

[Untyped]

Watching this thread. Had the same issue last winter on some very cold morning starts but forgot about it until now. FYI my timing chains have been updated.

JD

Glad to hear that this is happening to someone with for sure updated timing chains, since I don't have history on my recently purchased LR4. I was 99% sure that's not this sound.

One of the posts here suggests some kind of clutch in the fan... and I totally buy it!!

 

[Worzella]

Hi..

I just posted a new thread with apparently this same issue. I would not call it a clunk but rather a click..implying sharper pitch. But my situation seems to be identical. I have gotten no replies yet and am about to contact the shop that did my chains. ChatGPT strongly suggests telated to VVT and solenoids and as oil pressure builds and warms, the reason for the fade away sound.

My period of clicks is a bit different than yours but your video captures it perfectly. ChatGPT also indicated if it does not happen on warm start, certainty of VVT related goes up.

Here is my other post content:

2012 LR4 that I just had a quality timing chain/ coolant rework done. Motor purrs now and code free.

But after about 2 months on a cold start, I began hearing a periodic metallic click. After the idle lowers I hear this sound on the pass side of the motor. Have not been able to pinpoint because it is short lived. The click is sharp and happens about twice a second and will click about 5-10 times...then stop for maybe 10s...then repeat 5-10, etc.

It does this 5-10 click pattern about 4-5 times and each time it gets quieter until it just disappears. Not sure if it happens on warm start but will try to assess

 

[Jimmy Brooks]

Fan clutch, mine used to do this when I would go skiing. Super easy to replace if you want to do it on your own. Took me 5 mins and a rented viscous fan removal tool from O’Reillys