Roaring inside cab with A/C on - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jake Wade · 08-31-2013, 11:06 AM

85 GMC 1/2 ton 2WD with a 305. This truck has the R4 style compressor.

What could cause a roar inside the cab when the A/C is on that fluctuates with RPM. Unfortunately it is at its worse at cruise speed, 1800-2100 RPM.

Just installed a brand new Four seasons compressor, dryer, and orfice.

It has the proper oil and the charge is correct.

BTW, I have new motor mounts and all factory brackets installed correct.

Proper tension on new belts also.

Not noticeable standing outside looking under hood.

08-31-2013, 11:06 AM	#1
Jake Wade Registered User Join Date: Aug 2005 Location: Louisiana Posts: 711	Roaring inside cab with A/C on 85 GMC 1/2 ton 2WD with a 305. This truck has the R4 style compressor. What could cause a roar inside the cab when the A/C is on that fluctuates with RPM. Unfortunately it is at its worse at cruise speed, 1800-2100 RPM. Just installed a brand new Four seasons compressor, dryer, and orfice. It has the proper oil and the charge is correct. BTW, I have new motor mounts and all factory brackets installed correct. Proper tension on new belts also. Not noticeable standing outside looking under hood.



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