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I Just got my AC converted over from R12 and gassed up it hasnt been used in who knows how long but after getting new vacuum lines on the controls it seems to be working fine but...

when i let off the gas and the RPMS drop theres a very distinct rumble...you can feel it even in the steering and shifter i wouldnt say its loud ..although you can hear it and its comming from the compressor , it only does it while the AC is on and is not noticable at idle but ..rev it a bit and as the rps are dropping the rumble is there.

is this a bearing or maybe a clutch issue in the compressor? its not there when the AC is off

anyone had this?

cools fine ..i do wish my fan had more blow to it
 

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It's likely bracing.

Shoot a pic and post it

Also make sure your belt is fresh.

Likely the vibration of the belt is resonating through the engine.
 

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I Just got my AC converted over from R12 and gassed up it hasnt been used in who knows how long but after getting new vacuum lines on the controls it seems to be working fine but...

when i let off the gas and the RPMS drop theres a very distinct rumble...you can feel it even in the steering and shifter i wouldnt say its loud ..although you can hear it and its comming from the compressor , it only does it while the AC is on and is not noticable at idle but ..rev it a bit and as the rps are dropping the rumble is there.

is this a bearing or maybe a clutch issue in the compressor? its not there when the AC is off

anyone had this?

cools fine ..i do wish my fan had more blow to it

I can't help much with the vibrations, but the fan has a couple short comings and there are a few fixes.

First, the C4 was given a fan with the same bolt pattern but more fan blade surface area and a more aggressive pitch. The problem is you have to cut out a spacer so it fits in the box.




2nd, and this comes with changing the fan, the box is usually clogged with debris and leaves and such. It's just kind of normal. Clean out that box, make sure all your duct seals are in tact and tight and air flow will be improved.

Now, new replacement C3 fans will also run better than your 30 - 40 year old fan. They're just old and worn out and even if you don't upgrade to a C4 fan, upgrading to a new C3 fan will improve things quite a bit.
 

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It's likely bracing.

Shoot a pic and post it

Also make sure your belt is fresh.

Likely the vibration of the belt is resonating through the engine.

:agree:
 
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