Cold start knock

[Ultramaroon]

It can last for quite a while before it shits the bed, especially if the rest of the engine is clapped out enough to make only a fraction of its rated power. That was the case for my Eclipse. I never let the oil get too nasty from all the blow-by and it just ran and ran. Had the head off a few times and it was always nice and clean. I drove it for almost 300 Kmi.

[OwlDance]

Originally Posted by Sniepster

I am also quite perplexed as to how would this happen. It is 5w40 after all, not a thick-ass 10w60 racing oil.

Just because the oil doesn't feel much different than a lighter oil to the fingers doesn't mean it's working the same for something rotating dozens of times per second with sub mm clearances...

[radroach]

Probably your clutch throwout bearing.

[Sniepster]

Originally Posted by radroach

Probably your clutch throwout bearing.

No, that was changed relatively recently along the clutch fork and the pivot.

Not the same sound either.


UPDATE: I have changed the oil to a 5w30, i will let the car sit for at least a day and see if the sound is still there (or if it sounds just as bad). Fortunately the old oil does not seem to have metal particles in it. But i'll be conducting a UOA anyway.

[radroach]

May be your fuel quality. The couple times I've had a starting rattle was from low fuel and old fuel.
Other thought is maybe let your fuel pump prime for a second before turning the key.

[Sniepster]

Originally Posted by radroach

May be your fuel quality. The couple times I've had a starting rattle was from low fuel and old fuel.
Other thought is maybe let your fuel pump prime for a second before turning the key.

I only put 100 RON gas in it, pretty much the most premium you can find around in Romania. I believe it equals to 95 Pump to you guys across the pond.


UPDATE: The knock is still there but definitely less noticeable and goes away much faster after a cold start. In 3 weeks tops i should have my UOA results from Blackstone, fingers crossed!

[Bonburner]

I'd honestly use a 0W-30 for maximum cold protection (least viscosity while cold and still provide 30 weight hot protection).

[Ultramaroon]

Originally Posted by Bonburner

I'd honestly use a 0W-30 for maximum cold protection (least viscosity while cold and still provide 30 weight hot protection).

Old school band-aid is to use something thick like a straight-weight. @humfrz will back me up on the sawdust scheme. Quiets down the engine for a while.

[humfrz]

Originally Posted by Ultramaroon

Old school band-aid is to use something thick like a straight-weight. @humfrz will back me up on the sawdust scheme. Quiets down the engine for a while.

Oh yes, just before you sell a clunker, fill the crankcase with as heavy of oil that will go down the filler tube.

Yes, a handful of sawdust will help quiet the engine down. Sawdust is really effective at quieting a rear differential down (and transmissions, before they synchronized them).

[Sniepster]

Whilst browsing on YT i found this vid:

I think it's remarkable the engine in the video sounds EXACTLY like mine at cold start, same sound and same duration.

Do you guys think the VVT could be at fault for my sound also? I'm thinking since the oil acts as a hydraulic fluid for the VVT system it might've shit the bed by being too viscous, especially considering that our VVT system is quite similar to the one in the video above:

[Ultramaroon]

Different sound, unfortunately. Your's isn't a top-end rattle. It's a deep knock from only one rod.


Haha.... Brother's underwear and toothbrush.

[FrickingReallySlow]

I watch this guys channel extensively and sometimes his wife’s scarf makes an appearance...haha. His takeapart of the subaru boxer and why it fails is also a good watch. He buys notable seized engines like k20, VR30, FA20 and his bro’s toothbrush points out at all the potential problems

Originally Posted by Ultramaroon

Different sound, unfortunately. Your's isn't a top-end rattle. It's a deep knock from only one rod.


Haha.... Brother's underwear and toothbrush.

[Ultramaroon]

Originally Posted by FrickingReallySlow

I watch this guys channel extensively and sometimes his wife’s scarf makes an appearance...haha. His takeapart of the subaru boxer and why it fails is also a good watch. He buys notable seized engines like k20, VR30, FA20 and his bro’s toothbrush points out at all the potential problems

That's some good schtick. Thanks for mentioning it! I like how he locks into the subject and stays out of the frame. Looking forward to more of his stuff this weekend.

[Sportsguy83]

Originally Posted by Ultramaroon

It's early rod knock. Takes a couple seconds for the oil to pump up and hit the bearings from a cold start. Relying on thin film lubrication until then, and it's when worn journals will be most obvious.

Sorry. Sucks.

I can attest to this... I had a Camry that had "baby knock" on cold start for many many miles, until one day it decided it was time to let go and tansitioned to full on knock....