New AT4 and Cold Starts - Grinding Noise

[Maduro8]

So yes my old F150 with 350 000km would have some odd noises momentarily during really cold starts (sub -20C) but my new AT4 (4000km) is making a momentary concerning noise during cold startups and when I say cold I mean only around 0C to -3C (27-32F). Is this normal for a new engine?

https://imgur.com/a/qRHimzM

 

AT4 Forum Fav 👍

GM 3.0 Duramax Fuel system cap Magnetic Green - Grab one through Amazon!

[gemarsh]

Sounds like a high pressure steel line pressurizing up. Maybe a tranny line?

 

[elkchaser]

Normal, my HD 6 L did it and my AT4 6.2 does it when it is well below zero on the Celsius side or 32 to most guys on here. .. Kinda sounds like it is saying Frig, it's cold! A bit of a short whir and grind?

 

[Maduro8]

Normal, my HD 6 L did it and my AT4 6.2 does it when it is well below zero on the Celsius side or 32 to most guys on here. .. Kinda sounds like it is saying Frig, it's cold! A bit of a short whir and grind?

Thanks for the reply....but really? This is normal for a modern day advanced engine to do in mild temperatures such as -1C (30F)? My 20 year old Lexus doesn't even do this!

 

[Maduro8]

Update, local GM Dealer service foreman listened to it and tells me it's not normal. They've had my truck going on 12 days now trying to troubleshoot. Last update I received was that they've had numerous reports of this noise and they suspect the oil pump. Meanwhile it's sub zero temps here and the rental they gave me, a 2021 Sierra Elevation makes the same noise every morning! So I'm coming to my own conclusion that it's a normal abnormal sound. Meanwhile they tell me they are waiting for something called 'techline' to get back to them with what to do next. Anyone know what techline is? I'm getting frustrated they have taken so long and come up with so little.

 

[Maduro8]

A quick search of my problem with the words oil pump now turn up this:

GM Engine Noises During Cold Start, Warm Engine Operation

The new Small Block Generation 5 engine family incorporates a new fuel system technology known as direct injection (DI).

www.tomorrowstechnician.com

I'm not familiar with that site though and it's credibility.

 

[elkchaser]

I think you are overthinking this noise. Hey, it's cold and like us, a truck may have a few aches and pains getting going at these temperatures. All my GM vehicles made the same "groan" when it's really cold..

 

[24Titanium3500]

My 2015 makes that sound every start up. It now has close to 300k on it. My 24 3500 gasser makes the sound as well. I chocked it up as being the starter. I'll get a video today since they are both under a blanket of snow ready for cold starts!

 

[73Blazer]

My 2006 Sierra 5.3L made a similar sound when it was around 5 degrees out. I thought it may be the hydraulic lifters building pressure? I was never really worried about it. I still have that truck it's got 190k miles and runs perfect.

 

[24Titanium3500]

Here is the video of my 15' 1500 and 24' 3500 making the same sounds. Possible from the starters? Also could be fan clutch engagement sound. Not certain, but seems pretty normal. Both do this in what I believe/remember to be all temps. I'll pay more attn now.