cold start noise on 6.6 gasser

dgcat · January 18, 2020

had my 20 gasser for a month. usually only on cold starts after firing, it sounds like the bendix in the starter stays out for a second or so, or a clutch fan type noise. at least thats what it sounds like to me. has anyone noticed this ? thx

MShultz · January 18, 2020

Yes my 6.6L Gas makes the same noise.

dgcat · January 18, 2020

im going to have it checked out. doesnt seem right to me

dgcat · January 18, 2020

is it only a cold start?

SkidooSteve12 · January 21, 2020

Yesterday after work I started my truck while sitting in the cab and I could hear that short buzzing noise too, very briefly. Normally I remote start the truck as I'm walking to it so that it warms up sooner, so I never noticed it before. I should try and listen for it after it is warmed up.

dgcat · January 23, 2020

On 1/21/2020 at 7:55 AM, SkidooSteve12 said:

Yesterday after work I started my truck while sitting in the cab and I could hear that short buzzing noise too, very briefly. Normally I remote start the truck as I'm walking to it so that it warms up sooner, so I never noticed it before. I should try and listen for it after it is warmed up.

something is wrong , they will have a fix eventually but we have to complain first. the more i hear it it sounds like a clutch fan issue

MORSNO · January 23, 2020

It could also be the HVAC system damper door cycling through its range. I have a car with a "barking dog syndrome" that is caused by the HVAC system on start up.

SkidooSteve12 · January 27, 2020

I took a short video of a cold start today and you can hear the buzz after the engine is running.

Also, does it take other 6.6L gas engines that extra cranking to start up? It doesn't seem to fire up right away like my 5.3L would.

CamGTP · January 27, 2020

Sounds exactly like the oil pump that is a common thing on the 5.3/6.2's.

It only happens on cold starts in the winter time for me. The variable oil pump is pumping itself back full of oil.

bzales · January 31, 2020

My 2020 6.6 gas cold start makes the exact same noise as in SkidooSteve12’s video. Restart after warm up, no noise.
Thanks for sharing that video.

dgcat · February 9, 2020

On 1/26/2020 at 11:24 PM, CamGTP said:

Sounds exactly like the oil pump that is a common thing on the 5.3/6.2's.

It only happens on cold starts in the winter time for me. The variable oil pump is pumping itself back full of oil.

never heard that ,, anyone expand on that. i would think the oil pump should always have oil.

CamGTP · February 10, 2020

I found a article all about the newer oil pumps but I can't find it right now.

I remembered this from a previous thread though.

Quote

Oil Pump Cold Start Rrrrp or Rasp

The oil pump design has changed from a gerotor gear type pump to a two speed vane type pump for fuel economy reasons. At temperatures at or below 32°F (0°C) or when the engine has been sitting for a few hours, it is possible to have air enter the pump through normal oil drainback. Upon startup the owner may hear a short Rrrrp or Rasp coming from the front of the engine. It is most often heard during a remote start. There is nothing wrong with the oil pump or oil system. No repairs should be attempted for this condition.

Edited February 10, 2020 by CamGTP

KGray · February 17, 2020

On 2/9/2020 at 5:52 PM, CamGTP said:

I found a article all about the newer oil pumps but I can't find it right now.

I remembered this from a previous thread though.

On 1/18/2020 at 6:10 AM, dgcat said:

had my 20 gasser for a month. usually only on cold starts after firing, it sounds like the bendix in the starter stays out for a second or so, or a clutch fan type noise. at least thats what it sounds like to me. has anyone noticed this ? thx

I’ve got the same issue in my 2020 Silverado 2500 HD Custom with a 6.6 gasser... I’ve only got 500 miles on it. It’s January so the temp outside is around freezing here in Washington. Once the truck is warm the noise goes away on start up. I’ll be listening to see if it goes away when the weather warms up. I will most likely be taking it in for the Chevy dealer diagnose it. Super frustrating.

KGray · February 17, 2020

On 1/26/2020 at 8:24 PM, CamGTP said:

Sounds exactly like the oil pump that is a common thing on the 5.3/6.2's.

It only happens on cold starts in the winter time for me. The variable oil pump is pumping itself back full of oil.

Edited February 17, 2020 by KGray