2021 6.6L Duramax Diesel Cold Start ......

[Tucson Jack]

Hello,

When I start the Duramax 6.6L engine on cold starts and apply pressure to the brake pedal I can feel an "upward clunk or click" in the brake pedal with my foot.

This only happens on cold starts.

This is my 1st 2500HD Duramax and I'm just wondering if this is normal. I can not find anything about this in the Owners Manuals.

I called the Service Department at the Dealership and was told it has something to do with the Vacuum  System ?  I didn't really understand what he was saying. 

I will bring this to their attention when I get the 1st service.

The truck has only 550 miles as I've had it for only 10 days.

I can't remember if this has been happening since day 1.

Thank you .....

 

[MTU Alum]

These trucks use a brake assist system called hydroboost.  The power steering pump helps make assist for both the brakes and steering system.  You are likely just feeling the initial pressure build for assist after the power steering pump starts turning.  

 

Diesels don't make vacuum so you either need a vacuum pump, hydroboost, or eboost for brake assist.

 

#iworkforGM 

[Tucson Jack]

Hi MTU Alum,

Just a quick Thank You for replying to my 6.6L Duramax  Diesel Cold Start post.

Your reply was Spot On and is Much Appreciated.

I've owned Chevy  Silverados ( gas engines ) for many years and as some would say, I am Loyal to the Brand. 

This being my 1st Duramax and the Quality of the Build, Fit and Finish, Features, etc., this one is a Keeper !!

 

Best Regards,

Tucson Jack