2002 SVT Cobra Knocking Sound @ idle

2002SVT · 11-23-2008

When I start the car cold, I hear a loud and repetitive knocking sound from the front of the engine. This is at idling speeds. I notice the belt tensioner rocks violently when the sound occurs. This is very intermittent, and if i rev the engine, the sound goes away. It appears to be coming from the A/C compressor, could this be a sign that the A/C clutch bearing is going bad? The AC could be on or off and I still get the knocking. Anyone suffer from a similar problem and was able to fix it?

Mustangscotty · 11-23-2008

Never heard of that issue before but have you tried by-passing the air conditioner to see if the problem re-occurs? Inspect your fan belt carefully, its been stressed a lot !

lightning98 · 11-23-2008

lol there is no 02 cobra.

Mustangscotty · 11-23-2008

I was gonna say.. I owned an 01 Cobra and now own an 03 Cobra. Never knew there was such a thing as an 02 Cobra. Perhaps it was a left over from the 01 model year still at the dealership?

lightning98 · 11-23-2008

Nahh man its just a clone. you can see its got a gt hood also. lol i got a 02 gt cobra clone also

2002SVT · 11-23-2008

She's been modified to look like the 2000 Cobra R minus the hood and side exhaust.

Any idea about the problem thou?

Mustangscotty · 11-23-2008

Remove the fan belt and manually rotate the AC pulley and other pulleys, perhaps a bad bearing will reveal itself?

Tension pulleys have a tendency to go bad on 4.6L engines.

2002SVT · 11-23-2008

Took the tension pulley off and inspected the bearing. It appears to be fine. We did replace a different idler pulley, but the jerky knocking continued to persists. However, this morning, there was no knocking...it literally went away overnight. I'll continue to keep an ear out for it, but its running great now. Go figures!

Termn8torVert · 11-25-2008

Its not the A/c compressor kicking on and off is it? When they are low on freon the compressor will kick off and on alot and might be making that sound.

2002SVT · 11-26-2008

Quote:

Originally Posted by Termn8torVert

Its not the A/c compressor kicking on and off is it? When they are low on freon the compressor will kick off and on alot and might be making that sound.

The knocking occurs with the A/C off as well...so with the clutch not engaged, i don't think it could be the compressor....(at least I hope its not)