Is this for sound deadening? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**rs74** · 01-27-2015, 10:29 PM

I had never seen one of these covers over the AC box but was told is was for sound deadening since the truck is a diesel. My other diesel didn't have one but it could have been taken off long time ago.

Keith Seymore · 01-27-2015, 11:03 PM

Yes - diesel gets some additional sound deadening material.

**rs74** · 01-27-2015, 11:06 PM

Quote:

Originally Posted by Keith Seymore

Yes - diesel gets some additional sound deadening material.

Alright the man has spoken. Lol!.

Thanks Keith. I had just never saw one before. Obviously not been around alot of 6.2's. Probably got a pretty nice AC box underneath it. Just a little dirty I would assume.

ElGracho · 01-27-2015, 11:18 PM

It is. That one has been damaged for a fan motor replacement. Diesels also got the underhood pad and additional floor sound deadening.

That cover makes heater core replacement go from a 2 hour to a 6 or so hour job...

**rs74** · 01-27-2015, 11:48 PM

Quote:

Originally Posted by ElGracho

It is. That one has been damaged for a fan motor replacement. Diesels also got the underhood pad and additional floor sound deadening.

That cover makes heater core replacement go from a 2 hour to a 6 or so hour job...

Well then I hope I have no issues there then.

**rs74** · 01-28-2015, 10:26 AM

I went out and looked at that cover again. I didn't realize that it covers the whole firewall from one side to the other. Learned something new here.

Keith Seymore · 01-28-2015, 01:23 PM

The engine itself and powertrain related content came in under the engine RPO; there was a second interior RPO specified which brought in all the added insulation and sound deadening materials.

(1985 model year content shown)

K

**rs74** · 01-28-2015, 11:07 PM

That was a cool little read right there. Some pretty neat info on them. I laughed about the dual exhaust part. When I was down in Tennessee we pulled in to grab a bite to eat. There was a guy who started talking to me about it. Once he found out it was a diesel he said "Who in the hell puts duals on a diesel." Little did I know they are factory that way. I just blew it off thinking if it had not had duals on it then it was going to get them. I had them on my 6.2 K30 and liked it. This exhaust is pretty quiet compare to the K30.

Keith Seymore · 01-29-2015, 08:51 AM

Diesels are all about air flow.

They are flowing the maximum amount of air all the time (not like a gas engine, which is throttled by the carb/tbi blade position).

The more fuel you can put to 'em the more power they make, because the air is already there.

K

**rs74** · 01-29-2015, 10:27 AM

Quote:

Originally Posted by Keith Seymore

Diesels are all about air flow.

They are flowing the maximum amount of air all the time (not like a gas engine, which is throttled by the carb/tbi blade position).

The more fuel you can put to 'em the more power they make, because the air is already there.

K

I put my hand over the air breather intake tube and it was definitely pulling alot of air in.

01-27-2015, 10:29 PM	#1
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Is this for sound deadening? I had never seen one of these covers over the AC box but was told is was for sound deadening since the truck is a diesel. My other diesel didn't have one but it could have been taken off long time ago. Attached Images __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie Last edited by rs74; 01-27-2015 at 10:40 PM.

01-27-2015, 11:03 PM	#2
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,193	Re: Is this for sound deadening? Yes - diesel gets some additional sound deadening material. __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

01-27-2015, 11:18 PM	#4
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,550	Re: Is this for sound deadening? It is. That one has been damaged for a fan motor replacement. Diesels also got the underhood pad and additional floor sound deadening. That cover makes heater core replacement go from a 2 hour to a 6 or so hour job... __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

01-28-2015, 10:26 AM	#6
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Re: Is this for sound deadening? I went out and looked at that cover again. I didn't realize that it covers the whole firewall from one side to the other. Learned something new here. __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

01-28-2015, 01:23 PM	#7
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,193	Re: Is this for sound deadening? The engine itself and powertrain related content came in under the engine RPO; there was a second interior RPO specified which brought in all the added insulation and sound deadening materials. (1985 model year content shown) K Attached Images __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/

01-28-2015, 11:07 PM	#8
rs74 Senior Member Join Date: Jun 2010 Location: Illinois Posts: 2,957	Re: Is this for sound deadening? That was a cool little read right there. Some pretty neat info on them. I laughed about the dual exhaust part. When I was down in Tennessee we pulled in to grab a bite to eat. There was a guy who started talking to me about it. Once he found out it was a diesel he said "Who in the hell puts duals on a diesel." Little did I know they are factory that way. I just blew it off thinking if it had not had duals on it then it was going to get them. I had them on my 6.2 K30 and liked it. This exhaust is pretty quiet compare to the K30. __________________ Roy 85 Short Bed Silverado- Work in progress. http://67-72chevytrucks.com/vboard/s...d.php?t=564818 1987 R10 shortie

01-29-2015, 08:51 AM	#9
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,193	Re: Is this for sound deadening? Diesels are all about air flow. They are flowing the maximum amount of air all the time (not like a gas engine, which is throttled by the carb/tbi blade position). The more fuel you can put to 'em the more power they make, because the air is already there. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/



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