2008 Mustang 4.0 A/C ISSUE
6/8/17, 08:40 AM
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2008 Mustang 4.0 A/C ISSUE
I have 2008 Mustang 4.0 with a Manual Transmission, 115,000 miles. The car runs and drives very well. When the air conditioner is turned on, a rattle is heard from the engine compartment at a stop in neutral. When the clutch is pushed in, the noise goes away. My question to help find the problem, is if the air conditioner is disabled when the clutch pushed in?
6/9/17, 07:43 AM
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This was our first idea since the clutch was replaced a few months ago. We took the Mustang back to the shop and they replaced the TOB again and they said the one they replaced was good. This is a confusion problem since without running the A/C, the car runs great.
6/9/17, 02:15 PM
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Could it be a coincidence that your A/c was on when it happened or does it do it every single time the A/c's on? I'm asking because it sounds like an issue I have but I never use my A/c and it doesn't always do it
6/9/17, 08:12 PM
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The noise we here is every time we run the A/C. Our problem is most likely the A/C compressor, but I am trying to find out if the A/C unit is turned off when the clutch is applied and our noise goes away.
6/10/17, 03:39 AM
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Pretty sure it doesn't turn off . Easy way to find out hold the clutch in and turn the ac on keep it held in if it gets cold ac doesn't turn off with the clutch. I'm not a mechanic I don't want to lead you on. With your ac on your sapping power from other stuff which may not work correctly at half power. I think all of these models use the same master cylinder as the brake to power the clutch. I would start there. Someone correct me if I'm wrong
6/10/17, 09:49 AM
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The A/C clutch does not have anything to do whatsoever with the clutch of the transmission. It is always on except when the climate control doesn't want it on (say on regular, not max vent, and the A/C button is off, and you have fresh air selected, it would stay off), or you are using Wide Open Throttle (whereupon you want all power available for the engine, so turning off the A/C clutch briefly while you're race-car is the answer for that.)
That it goes away when the clutch pedal is depressed indicates it has nothing to do with the A/C.
I would say turn off the A/C and you should hear the problem still. If you do not, the problem is with the A/C compressor. I am almost ready to put money down that you still hear the problem in this configuration.
And since the clutch pedal is depressed and the noise goes away, that is two things possible: Something in the clutch (most likely a bad out of the box throwout bearing, but only one way to find out) or something in the T-5 Transmission.
Definitely the only way to get it figured out is to take it to the shop and put it up on the rack with someone in the car doing whatever is needed to the A/C and clutch to recreate the noise and another person listening for where it is. You can do this at home, get it up on jackstands or wheel ramps, and have someone do the stuff while you listen... or vice versa.
But if you're disinclined to do it, your shop should be happy to do it for you. And if this shop won't do it for you, there's other shops what'll be happy to have you for a customer, y'know.
Hope that helps. If it winds up being the exhaust, that'll be interesting.
Good luck! 
---
Edit: HAAY... I just thought of something after rattlin' off all that... There *is* a situation where that could be happening... but you won't like it, and I hope it's not the case.
It has to do with my telling of WOT situation... and then it got me to thinking about the load on the engine that the A/C compressor puts on it...and then... light bulb.
It's entirely possible the rattling you're hearing is in the engine if the A/C is on and you have the clutch engaged. The extra load makes extra work, and therefore something in the engine... crank bearings, main bearings, or knocking from bad gas, possibly the pilot bearing... that's being 'activated'. This would be because in addition to the A/C load, the clutch being engaged means the spinning of the clutch pack, and the input shaft of the transmission, adds to that load some more... and there ya go, engine is making a rattle. It ordinarily shouldn't be much, but... it's entirely possible it's not even the engine, but something in the transmission that's dragging the engine, thereby causing the issue.
Whatever would cause it that way, I *sincerely* hope that's not the case. But... I had to put it out there. Probably not... I hope...
Ok, I think that's all I got. Again, good luck!
That it goes away when the clutch pedal is depressed indicates it has nothing to do with the A/C.
I would say turn off the A/C and you should hear the problem still. If you do not, the problem is with the A/C compressor. I am almost ready to put money down that you still hear the problem in this configuration.
And since the clutch pedal is depressed and the noise goes away, that is two things possible: Something in the clutch (most likely a bad out of the box throwout bearing, but only one way to find out) or something in the T-5 Transmission.
Definitely the only way to get it figured out is to take it to the shop and put it up on the rack with someone in the car doing whatever is needed to the A/C and clutch to recreate the noise and another person listening for where it is. You can do this at home, get it up on jackstands or wheel ramps, and have someone do the stuff while you listen... or vice versa.
But if you're disinclined to do it, your shop should be happy to do it for you. And if this shop won't do it for you, there's other shops what'll be happy to have you for a customer, y'know.
Hope that helps. If it winds up being the exhaust, that'll be interesting.
Good luck! ---
Edit: HAAY... I just thought of something after rattlin' off all that... There *is* a situation where that could be happening... but you won't like it, and I hope it's not the case.
It has to do with my telling of WOT situation... and then it got me to thinking about the load on the engine that the A/C compressor puts on it...and then... light bulb.
It's entirely possible the rattling you're hearing is in the engine if the A/C is on and you have the clutch engaged. The extra load makes extra work, and therefore something in the engine... crank bearings, main bearings, or knocking from bad gas, possibly the pilot bearing... that's being 'activated'. This would be because in addition to the A/C load, the clutch being engaged means the spinning of the clutch pack, and the input shaft of the transmission, adds to that load some more... and there ya go, engine is making a rattle. It ordinarily shouldn't be much, but... it's entirely possible it's not even the engine, but something in the transmission that's dragging the engine, thereby causing the issue.
Whatever would cause it that way, I *sincerely* hope that's not the case. But... I had to put it out there. Probably not... I hope...
Ok, I think that's all I got. Again, good luck!
Last edited by houtex; 6/10/17 at 09:56 AM.
6/10/17, 06:17 PM
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The A/C clutch does not have anything to do whatsoever with the clutch of the transmission. It is always on except when the climate control doesn't want it on (say on regular, not max vent, and the A/C button is off, and you have fresh air selected, it would stay off), or you are using Wide Open Throttle (whereupon you want all power available for the engine, so turning off the A/C clutch briefly while you're race-car is the answer for that.)
That it goes away when the clutch pedal is depressed indicates it has nothing to do with the A/C.
I would say turn off the A/C and you should hear the problem still. If you do not, the problem is with the A/C compressor. I am almost ready to put money down that you still hear the problem in this configuration.
And since the clutch pedal is depressed and the noise goes away, that is two things possible: Something in the clutch (most likely a bad out of the box throwout bearing, but only one way to find out) or something in the T-5 Transmission.
Definitely the only way to get it figured out is to take it to the shop and put it up on the rack with someone in the car doing whatever is needed to the A/C and clutch to recreate the noise and another person listening for where it is. You can do this at home, get it up on jackstands or wheel ramps, and have someone do the stuff while you listen... or vice versa.
But if you're disinclined to do it, your shop should be happy to do it for you. And if this shop won't do it for you, there's other shops what'll be happy to have you for a customer, y'know.
Hope that helps. If it winds up being the exhaust, that'll be interesting. Good luck!
---
Edit: HAAY... I just thought of something after rattlin' off all that... There *is* a situation where that could be happening... but you won't like it, and I hope it's not the case.
It has to do with my telling of WOT situation... and then it got me to thinking about the load on the engine that the A/C compressor puts on it...and then... light bulb.
It's entirely possible the rattling you're hearing is in the engine if the A/C is on and you have the clutch engaged. The extra load makes extra work, and therefore something in the engine... crank bearings, main bearings, or knocking from bad gas, possibly the pilot bearing... that's being 'activated'. This would be because in addition to the A/C load, the clutch being engaged means the spinning of the clutch pack, and the input shaft of the transmission, adds to that load some more... and there ya go, engine is making a rattle. It ordinarily shouldn't be much, but... it's entirely possible it's not even the engine, but something in the transmission that's dragging the engine, thereby causing the issue.
Whatever would cause it that way, I *sincerely* hope that's not the case. But... I had to put it out there. Probably not... I hope...
Ok, I think that's all I got. Again, good luck!
That it goes away when the clutch pedal is depressed indicates it has nothing to do with the A/C.
I would say turn off the A/C and you should hear the problem still. If you do not, the problem is with the A/C compressor. I am almost ready to put money down that you still hear the problem in this configuration.
And since the clutch pedal is depressed and the noise goes away, that is two things possible: Something in the clutch (most likely a bad out of the box throwout bearing, but only one way to find out) or something in the T-5 Transmission.
Definitely the only way to get it figured out is to take it to the shop and put it up on the rack with someone in the car doing whatever is needed to the A/C and clutch to recreate the noise and another person listening for where it is. You can do this at home, get it up on jackstands or wheel ramps, and have someone do the stuff while you listen... or vice versa.
But if you're disinclined to do it, your shop should be happy to do it for you. And if this shop won't do it for you, there's other shops what'll be happy to have you for a customer, y'know.
Hope that helps. If it winds up being the exhaust, that'll be interesting.
Good luck! ---
Edit: HAAY... I just thought of something after rattlin' off all that... There *is* a situation where that could be happening... but you won't like it, and I hope it's not the case.
It has to do with my telling of WOT situation... and then it got me to thinking about the load on the engine that the A/C compressor puts on it...and then... light bulb.
It's entirely possible the rattling you're hearing is in the engine if the A/C is on and you have the clutch engaged. The extra load makes extra work, and therefore something in the engine... crank bearings, main bearings, or knocking from bad gas, possibly the pilot bearing... that's being 'activated'. This would be because in addition to the A/C load, the clutch being engaged means the spinning of the clutch pack, and the input shaft of the transmission, adds to that load some more... and there ya go, engine is making a rattle. It ordinarily shouldn't be much, but... it's entirely possible it's not even the engine, but something in the transmission that's dragging the engine, thereby causing the issue.
Whatever would cause it that way, I *sincerely* hope that's not the case. But... I had to put it out there. Probably not... I hope...
Ok, I think that's all I got. Again, good luck!
